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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<!-- Generated by HsColour, http://code.haskell.org/~malcolm/hscolour/ -->
<title>src/Data/Bifunctor/TH.hs</title>
<link type='text/css' rel='stylesheet' href='hscolour.css' />
</head>
<body>
<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP #-}</span>
<a name="line-2"></a><span class='hs-comment'>{-# LANGUAGE PatternGuards #-}</span>
<a name="line-3"></a><span class='hs-comment'>{-# LANGUAGE BangPatterns #-}</span>
<a name="line-4"></a>
<a name="line-5"></a><span class='hs-cpp'>#if __GLASGOW_HASKELL__ &gt;= 704</span>
<a name="line-6"></a><span class='hs-comment'>{-# LANGUAGE Unsafe #-}</span>
<a name="line-7"></a><span class='hs-cpp'>#endif</span>
<a name="line-8"></a>
<a name="line-9"></a><span class='hs-cpp'>#ifndef MIN_VERSION_template_haskell</span>
<a name="line-10"></a><span class='hs-cpp'>#define MIN_VERSION_template_haskell(x,y,z) 1</span>
<a name="line-11"></a><span class='hs-cpp'>#endif</span>
<a name="line-12"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-13"></a><span class='hs-comment'>-- |</span>
<a name="line-14"></a><span class='hs-comment'>-- Copyright   :  (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott</span>
<a name="line-15"></a><span class='hs-comment'>-- License     :  BSD-style (see the file LICENSE)</span>
<a name="line-16"></a><span class='hs-comment'>--</span>
<a name="line-17"></a><span class='hs-comment'>-- Maintainer  :  Edward Kmett &lt;ekmett@gmail.com&gt;</span>
<a name="line-18"></a><span class='hs-comment'>-- Stability   :  provisional</span>
<a name="line-19"></a><span class='hs-comment'>-- Portability :  portable</span>
<a name="line-20"></a><span class='hs-comment'>--</span>
<a name="line-21"></a><span class='hs-comment'>-- Functions to mechanically derive 'Bifunctor', 'Bifoldable',</span>
<a name="line-22"></a><span class='hs-comment'>-- or 'Bitraversable' instances, or to splice their functions directly into</span>
<a name="line-23"></a><span class='hs-comment'>-- source code. You need to enable the @TemplateHaskell@ language extension</span>
<a name="line-24"></a><span class='hs-comment'>-- in order to use this module.</span>
<a name="line-25"></a><span class='hs-comment'>----------------------------------------------------------------------------</span>
<a name="line-26"></a>
<a name="line-27"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Bifunctor</span><span class='hs-varop'>.</span><span class='hs-conid'>TH</span> <span class='hs-layout'>(</span>
<a name="line-28"></a>    <span class='hs-comment'>-- * @derive@- functions</span>
<a name="line-29"></a>    <span class='hs-comment'>-- $derive</span>
<a name="line-30"></a>    <span class='hs-comment'>-- * @make@- functions</span>
<a name="line-31"></a>    <span class='hs-comment'>-- $make</span>
<a name="line-32"></a>    <span class='hs-comment'>-- * 'Bifunctor'</span>
<a name="line-33"></a>    <span class='hs-varid'>deriveBifunctor</span>
<a name="line-34"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBimap</span>
<a name="line-35"></a>    <span class='hs-comment'>-- * 'Bifoldable'</span>
<a name="line-36"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>deriveBifoldable</span>
<a name="line-37"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBifold</span>
<a name="line-38"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBifoldMap</span>
<a name="line-39"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBifoldr</span>
<a name="line-40"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBifoldl</span>
<a name="line-41"></a>    <span class='hs-comment'>-- * 'Bitraversable'</span>
<a name="line-42"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>deriveBitraversable</span>
<a name="line-43"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBitraverse</span>
<a name="line-44"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBisequenceA</span>
<a name="line-45"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBimapM</span>
<a name="line-46"></a>  <span class='hs-layout'>,</span> <span class='hs-varid'>makeBisequence</span>
<a name="line-47"></a>  <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-48"></a>
<a name="line-49"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-varid'>guard</span><span class='hs-layout'>,</span> <span class='hs-varid'>unless</span><span class='hs-layout'>,</span> <span class='hs-varid'>when</span><span class='hs-layout'>,</span> <span class='hs-varid'>zipWithM</span><span class='hs-layout'>)</span>
<a name="line-50"></a>
<a name="line-51"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Bifunctor</span><span class='hs-varop'>.</span><span class='hs-conid'>TH</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span>
<a name="line-52"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Either</span> <span class='hs-layout'>(</span><span class='hs-varid'>rights</span><span class='hs-layout'>)</span>
<a name="line-53"></a><span class='hs-cpp'>#if MIN_VERSION_template_haskell(2,8,0) &amp;&amp; !(MIN_VERSION_template_haskell(2,10,0))</span>
<a name="line-54"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Foldable</span> <span class='hs-layout'>(</span><span class='hs-varid'>foldr'</span><span class='hs-layout'>)</span>
<a name="line-55"></a><span class='hs-cpp'>#endif</span>
<a name="line-56"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
<a name="line-57"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>Map</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromList</span><span class='hs-layout'>,</span> <span class='hs-varid'>keys</span><span class='hs-layout'>,</span> <span class='hs-varid'>lookup</span><span class='hs-layout'>,</span> <span class='hs-varid'>size</span><span class='hs-layout'>)</span>
<a name="line-58"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Maybe</span>
<a name="line-59"></a>
<a name="line-60"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Language</span><span class='hs-varop'>.</span><span class='hs-conid'>Haskell</span><span class='hs-varop'>.</span><span class='hs-conid'>TH</span><span class='hs-varop'>.</span><span class='hs-conid'>Lib</span>
<a name="line-61"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Language</span><span class='hs-varop'>.</span><span class='hs-conid'>Haskell</span><span class='hs-varop'>.</span><span class='hs-conid'>TH</span><span class='hs-varop'>.</span><span class='hs-conid'>Ppr</span>
<a name="line-62"></a><span class='hs-keyword'>import</span>           <span class='hs-conid'>Language</span><span class='hs-varop'>.</span><span class='hs-conid'>Haskell</span><span class='hs-varop'>.</span><span class='hs-conid'>TH</span><span class='hs-varop'>.</span><span class='hs-conid'>Syntax</span>
<a name="line-63"></a>
<a name="line-64"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-65"></a><span class='hs-comment'>-- User-facing API</span>
<a name="line-66"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-67"></a>
<a name="line-68"></a><span class='hs-comment'>{- $derive
<a name="line-69"></a>
<a name="line-70"></a>'deriveBifunctor', 'deriveBifoldable', and 'deriveBitraversable' automatically
<a name="line-71"></a>generate their respective class instances for a given data type, newtype, or data
<a name="line-72"></a>family instance that has at least two type variable. Examples:
<a name="line-73"></a>
<a name="line-74"></a>@
<a name="line-75"></a>&amp;#123;-&amp;#35; LANGUAGE TemplateHaskell &amp;#35;-&amp;#125;
<a name="line-76"></a>import Data.Bifunctor.TH
<a name="line-77"></a>
<a name="line-78"></a>data Pair a b = Pair a b
<a name="line-79"></a>$('deriveBifunctor' ''Pair) -- instance Bifunctor Pair where ...
<a name="line-80"></a>
<a name="line-81"></a>data WrapLeftPair f g a b = WrapLeftPair (f a) (g a b)
<a name="line-82"></a>$('deriveBifoldable' ''WrapLeftPair)
<a name="line-83"></a>-- instance (Foldable f, Bifoldable g) =&gt; Bifoldable (WrapLeftPair f g) where ...
<a name="line-84"></a>@
<a name="line-85"></a>
<a name="line-86"></a>If you are using @template-haskell-2.7.0.0@ or later (i.e., GHC 7.4 or later),
<a name="line-87"></a>the @derive@ functions can be used data family instances (which requires the
<a name="line-88"></a>@-XTypeFamilies@ extension). To do so, pass the name of a data or newtype instance
<a name="line-89"></a>constructor (NOT a data family name!) to a @derive@ function.  Note that the
<a name="line-90"></a>generated code may require the @-XFlexibleInstances@ extension. Example:
<a name="line-91"></a>
<a name="line-92"></a>@
<a name="line-93"></a>&amp;#123;-&amp;#35; LANGUAGE FlexibleInstances, TemplateHaskell, TypeFamilies &amp;#35;-&amp;#125;
<a name="line-94"></a>import Data.Bifunctor.TH
<a name="line-95"></a>
<a name="line-96"></a>class AssocClass a b c where
<a name="line-97"></a>    data AssocData a b c
<a name="line-98"></a>instance AssocClass Int b c where
<a name="line-99"></a>    data AssocData Int b c = AssocDataInt1 Int | AssocDataInt2 b c
<a name="line-100"></a>$('deriveBitraversable' 'AssocDataInt1) -- instance Bitraversable (AssocData Int) where ...
<a name="line-101"></a>-- Alternatively, one could use $(deriveBitraversable 'AssocDataInt2)
<a name="line-102"></a>@
<a name="line-103"></a>
<a name="line-104"></a>Note that there are some limitations:
<a name="line-105"></a>
<a name="line-106"></a>* The 'Name' argument to a @derive@ function must not be a type synonym.
<a name="line-107"></a>
<a name="line-108"></a>* With a @derive@ function, the last two type variables must both be of kind @*@.
<a name="line-109"></a>  Other type variables of kind @* -&gt; *@ are assumed to require a 'Functor',
<a name="line-110"></a>  'Foldable', or 'Traversable' constraint (depending on which @derive@ function is
<a name="line-111"></a>  used), and other type variables of kind @* -&gt; * -&gt; *@ are assumed to require an
<a name="line-112"></a>  'Bifunctor', 'Bifoldable', or 'Bitraversable' constraint. If your data type
<a name="line-113"></a>  doesn't meet these assumptions, use a @make@ function.
<a name="line-114"></a>
<a name="line-115"></a>* If using the @-XDatatypeContexts@, @-XExistentialQuantification@, or @-XGADTs@
<a name="line-116"></a>  extensions, a constraint cannot mention either of the last two type variables. For
<a name="line-117"></a>  example, @data Illegal2 a b where I2 :: Ord a =&gt; a -&gt; b -&gt; Illegal2 a b@ cannot
<a name="line-118"></a>  have a derived 'Bifunctor' instance.
<a name="line-119"></a>
<a name="line-120"></a>* If either of the last two type variables is used within a constructor argument's
<a name="line-121"></a>  type, it must only be used in the last two type arguments. For example,
<a name="line-122"></a>  @data Legal a b = Legal (Int, Int, a, b)@ can have a derived 'Bifunctor' instance,
<a name="line-123"></a>  but @data Illegal a b = Illegal (a, b, a, b)@ cannot.
<a name="line-124"></a>
<a name="line-125"></a>* Data family instances must be able to eta-reduce the last two type variables. In other
<a name="line-126"></a>  words, if you have a instance of the form:
<a name="line-127"></a>
<a name="line-128"></a>  @
<a name="line-129"></a>  data family Family a1 ... an t1 t2
<a name="line-130"></a>  data instance Family e1 ... e2 v1 v2 = ...
<a name="line-131"></a>  @
<a name="line-132"></a>
<a name="line-133"></a>  Then the following conditions must hold:
<a name="line-134"></a>
<a name="line-135"></a>  1. @v1@ and @v2@ must be distinct type variables.
<a name="line-136"></a>  2. Neither @v1@ not @v2@ must be mentioned in any of @e1@, ..., @e2@.
<a name="line-137"></a>
<a name="line-138"></a>-}</span>
<a name="line-139"></a>
<a name="line-140"></a><span class='hs-comment'>{- $make
<a name="line-141"></a>
<a name="line-142"></a>There may be scenarios in which you want to, say, 'bimap' over an arbitrary data type
<a name="line-143"></a>or data family instance without having to make the type an instance of 'Bifunctor'. For
<a name="line-144"></a>these cases, this module provides several functions (all prefixed with @make@-) that
<a name="line-145"></a>splice the appropriate lambda expression into your source code.
<a name="line-146"></a>
<a name="line-147"></a>This is particularly useful for creating instances for sophisticated data types. For
<a name="line-148"></a>example, 'deriveBifunctor' cannot infer the correct type context for
<a name="line-149"></a>@newtype HigherKinded f a b c = HigherKinded (f a b c)@, since @f@ is of kind
<a name="line-150"></a>@* -&gt; * -&gt; * -&gt; *@. However, it is still possible to create a 'Bifunctor' instance for
<a name="line-151"></a>@HigherKinded@ without too much trouble using 'makeBimap':
<a name="line-152"></a>
<a name="line-153"></a>@
<a name="line-154"></a>&amp;#123;-&amp;#35; LANGUAGE FlexibleContexts, TemplateHaskell &amp;#35;-&amp;#125;
<a name="line-155"></a>import Data.Bifunctor
<a name="line-156"></a>import Data.Bifunctor.TH
<a name="line-157"></a>
<a name="line-158"></a>newtype HigherKinded f a b c = HigherKinded (f a b c)
<a name="line-159"></a>
<a name="line-160"></a>instance Bifunctor (f a) =&gt; Bifunctor (HigherKinded f a) where
<a name="line-161"></a>    bimap = $(makeBimap ''HigherKinded)
<a name="line-162"></a>@
<a name="line-163"></a>
<a name="line-164"></a>-}</span>
<a name="line-165"></a>
<a name="line-166"></a><a name="deriveBifunctor"></a><span class='hs-comment'>-- | Generates a 'Bifunctor' instance declaration for the given data type or data</span>
<a name="line-167"></a><span class='hs-comment'>-- family instance.</span>
<a name="line-168"></a><span class='hs-definition'>deriveBifunctor</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-169"></a><span class='hs-definition'>deriveBifunctor</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>deriveBiClass</span> <span class='hs-conid'>Bifunctor</span>
<a name="line-170"></a>
<a name="line-171"></a><a name="makeBimap"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bimap' (without requiring a</span>
<a name="line-172"></a><span class='hs-comment'>-- 'Bifunctor' instance).</span>
<a name="line-173"></a><span class='hs-definition'>makeBimap</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-174"></a><span class='hs-definition'>makeBimap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeBiFun</span> <span class='hs-conid'>Bimap</span>
<a name="line-175"></a>
<a name="line-176"></a><a name="deriveBifoldable"></a><span class='hs-comment'>-- | Generates a 'Bifoldable' instance declaration for the given data type or data</span>
<a name="line-177"></a><span class='hs-comment'>-- family instance.</span>
<a name="line-178"></a><span class='hs-definition'>deriveBifoldable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-179"></a><span class='hs-definition'>deriveBifoldable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>deriveBiClass</span> <span class='hs-conid'>Bifoldable</span>
<a name="line-180"></a>
<a name="line-181"></a><a name="makeBifold"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bifold' (without requiring a</span>
<a name="line-182"></a><span class='hs-comment'>-- 'Bifoldable' instance).</span>
<a name="line-183"></a><span class='hs-definition'>makeBifold</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-184"></a><span class='hs-definition'>makeBifold</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>makeBifoldMap</span> <span class='hs-varid'>name</span>
<a name="line-185"></a>                        <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-186"></a>                        <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-187"></a>                        <span class='hs-keyglyph'>]</span>
<a name="line-188"></a>
<a name="line-189"></a><a name="makeBifoldMap"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bifoldMap' (without requiring a</span>
<a name="line-190"></a><span class='hs-comment'>-- 'Bifoldable' instance).</span>
<a name="line-191"></a><span class='hs-definition'>makeBifoldMap</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-192"></a><span class='hs-definition'>makeBifoldMap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeBiFun</span> <span class='hs-conid'>BifoldMap</span>
<a name="line-193"></a>
<a name="line-194"></a><a name="makeBifoldr"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bifoldr' (without requiring a</span>
<a name="line-195"></a><span class='hs-comment'>-- 'Bifoldable' instance).</span>
<a name="line-196"></a><span class='hs-definition'>makeBifoldr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-197"></a><span class='hs-definition'>makeBifoldr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeBiFun</span> <span class='hs-conid'>Bifoldr</span>
<a name="line-198"></a>
<a name="line-199"></a><a name="makeBifoldl"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bifoldl' (without requiring a</span>
<a name="line-200"></a><span class='hs-comment'>-- 'Bifoldable' instance).</span>
<a name="line-201"></a><span class='hs-definition'>makeBifoldl</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-202"></a><span class='hs-definition'>makeBifoldl</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-203"></a>  <span class='hs-varid'>f</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"f"</span>
<a name="line-204"></a>  <span class='hs-varid'>g</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"g"</span>
<a name="line-205"></a>  <span class='hs-varid'>z</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"z"</span>
<a name="line-206"></a>  <span class='hs-varid'>t</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"t"</span>
<a name="line-207"></a>  <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>varP</span> <span class='hs-varid'>f</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>g</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>z</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span>
<a name="line-208"></a>    <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>appEndoValName</span>
<a name="line-209"></a>          <span class='hs-layout'>,</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>getDualValName</span>
<a name="line-210"></a>                  <span class='hs-layout'>,</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>makeBifoldMap</span> <span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>foldFun</span> <span class='hs-varid'>f</span><span class='hs-layout'>,</span> <span class='hs-varid'>foldFun</span> <span class='hs-varid'>g</span><span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>]</span>
<a name="line-211"></a>                  <span class='hs-keyglyph'>]</span>
<a name="line-212"></a>          <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>z</span>
<a name="line-213"></a>          <span class='hs-keyglyph'>]</span>
<a name="line-214"></a>  <span class='hs-keyword'>where</span>
<a name="line-215"></a>    <span class='hs-varid'>foldFun</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-216"></a>    <span class='hs-varid'>foldFun</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>infixApp</span> <span class='hs-layout'>(</span><span class='hs-varid'>conE</span> <span class='hs-varid'>dualDataName</span><span class='hs-layout'>)</span>
<a name="line-217"></a>                         <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>composeValName</span><span class='hs-layout'>)</span>
<a name="line-218"></a>                         <span class='hs-layout'>(</span><span class='hs-varid'>infixApp</span> <span class='hs-layout'>(</span><span class='hs-varid'>conE</span> <span class='hs-varid'>endoDataName</span><span class='hs-layout'>)</span>
<a name="line-219"></a>                                   <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>composeValName</span><span class='hs-layout'>)</span>
<a name="line-220"></a>                                   <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>flipValName</span> <span class='hs-varop'>`appE`</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-221"></a>                         <span class='hs-layout'>)</span>
<a name="line-222"></a>
<a name="line-223"></a><a name="deriveBitraversable"></a><span class='hs-comment'>-- | Generates a 'Bitraversable' instance declaration for the given data type or data</span>
<a name="line-224"></a><span class='hs-comment'>-- family instance.</span>
<a name="line-225"></a><span class='hs-definition'>deriveBitraversable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-226"></a><span class='hs-definition'>deriveBitraversable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>deriveBiClass</span> <span class='hs-conid'>Bitraversable</span>
<a name="line-227"></a>
<a name="line-228"></a><a name="makeBitraverse"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bitraverse' (without requiring a</span>
<a name="line-229"></a><span class='hs-comment'>-- 'Bitraversable' instance).</span>
<a name="line-230"></a><span class='hs-definition'>makeBitraverse</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-231"></a><span class='hs-definition'>makeBitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeBiFun</span> <span class='hs-conid'>Bitraverse</span>
<a name="line-232"></a>
<a name="line-233"></a><a name="makeBisequenceA"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bisequenceA' (without requiring a</span>
<a name="line-234"></a><span class='hs-comment'>-- 'Bitraversable' instance).</span>
<a name="line-235"></a><span class='hs-definition'>makeBisequenceA</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-236"></a><span class='hs-definition'>makeBisequenceA</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>makeBitraverse</span> <span class='hs-varid'>name</span>
<a name="line-237"></a>                             <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-238"></a>                             <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-239"></a>                             <span class='hs-keyglyph'>]</span>
<a name="line-240"></a>
<a name="line-241"></a><a name="makeBimapM"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bimapM' (without requiring a</span>
<a name="line-242"></a><span class='hs-comment'>-- 'Bitraversable' instance).</span>
<a name="line-243"></a><span class='hs-definition'>makeBimapM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-244"></a><span class='hs-definition'>makeBimapM</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-245"></a>  <span class='hs-varid'>f</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"f"</span>
<a name="line-246"></a>  <span class='hs-varid'>g</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"g"</span>
<a name="line-247"></a>  <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>varP</span> <span class='hs-varid'>f</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>g</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>.</span> <span class='hs-varid'>infixApp</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>unwrapMonadValName</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>composeValName</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-248"></a>                          <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>makeBitraverse</span> <span class='hs-varid'>name</span><span class='hs-layout'>,</span> <span class='hs-varid'>wrapMonadExp</span> <span class='hs-varid'>f</span><span class='hs-layout'>,</span> <span class='hs-varid'>wrapMonadExp</span> <span class='hs-varid'>g</span><span class='hs-keyglyph'>]</span>
<a name="line-249"></a>  <span class='hs-keyword'>where</span>
<a name="line-250"></a>    <span class='hs-varid'>wrapMonadExp</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-251"></a>    <span class='hs-varid'>wrapMonadExp</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>infixApp</span> <span class='hs-layout'>(</span><span class='hs-varid'>conE</span> <span class='hs-varid'>wrapMonadDataName</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>composeValName</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-252"></a>
<a name="line-253"></a><a name="makeBisequence"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like 'bisequence' (without requiring a</span>
<a name="line-254"></a><span class='hs-comment'>-- 'Bitraversable' instance).</span>
<a name="line-255"></a><span class='hs-definition'>makeBisequence</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-256"></a><span class='hs-definition'>makeBisequence</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>makeBimapM</span> <span class='hs-varid'>name</span>
<a name="line-257"></a>                            <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-258"></a>                            <span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>idValName</span>
<a name="line-259"></a>                            <span class='hs-keyglyph'>]</span>
<a name="line-260"></a>
<a name="line-261"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-262"></a><span class='hs-comment'>-- Code generation</span>
<a name="line-263"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-264"></a>
<a name="line-265"></a><a name="deriveBiClass"></a><span class='hs-comment'>-- | Derive a class instance declaration (depending on the BiClass argument's value).</span>
<a name="line-266"></a><span class='hs-definition'>deriveBiClass</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-267"></a><span class='hs-definition'>deriveBiClass</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>withType</span> <span class='hs-varid'>name</span> <span class='hs-varid'>fromCons</span> <span class='hs-keyword'>where</span>
<a name="line-268"></a>  <span class='hs-varid'>fromCons</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Cxt</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVarBndr</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Con</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-269"></a>  <span class='hs-varid'>fromCons</span> <span class='hs-varid'>name'</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>cons</span> <span class='hs-varid'>mbTys</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conop'>:</span><span class='hs-conid'>[]</span><span class='hs-layout'>)</span> <span class='hs-varop'>`fmap`</span> <span class='hs-keyword'>do</span>
<a name="line-270"></a>    <span class='hs-layout'>(</span><span class='hs-varid'>instanceCxt</span><span class='hs-layout'>,</span> <span class='hs-varid'>instanceType</span><span class='hs-layout'>)</span>
<a name="line-271"></a>        <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>buildTypeInstance</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>name'</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>mbTys</span>
<a name="line-272"></a>    <span class='hs-varid'>instanceD</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varid'>instanceCxt</span><span class='hs-layout'>)</span>
<a name="line-273"></a>              <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varid'>instanceType</span><span class='hs-layout'>)</span>
<a name="line-274"></a>              <span class='hs-layout'>(</span><span class='hs-varid'>biFunDecs</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>cons</span><span class='hs-layout'>)</span>
<a name="line-275"></a>
<a name="line-276"></a><a name="biFunDecs"></a><span class='hs-comment'>-- | Generates a declaration defining the primary function(s) corresponding to a</span>
<a name="line-277"></a><span class='hs-comment'>-- particular class (bimap for Bifunctor, bifoldr and bifoldMap for Bifoldable, and</span>
<a name="line-278"></a><span class='hs-comment'>-- bitraverse for Bitraversable).</span>
<a name="line-279"></a><span class='hs-comment'>--</span>
<a name="line-280"></a><span class='hs-comment'>-- For why both bifoldr and bifoldMap are derived for Bifoldable, see Trac #7436.</span>
<a name="line-281"></a><span class='hs-definition'>biFunDecs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Con</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Q</span> <span class='hs-conid'>Dec</span><span class='hs-keyglyph'>]</span>
<a name="line-282"></a><span class='hs-definition'>biFunDecs</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>cons</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>makeFunD</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biClassToFuns</span> <span class='hs-varid'>biClass</span> <span class='hs-keyword'>where</span>
<a name="line-283"></a>  <span class='hs-varid'>makeFunD</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Dec</span>
<a name="line-284"></a>  <span class='hs-varid'>makeFunD</span> <span class='hs-varid'>biFun</span> <span class='hs-keyglyph'>=</span>
<a name="line-285"></a>    <span class='hs-varid'>funD</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFunName</span> <span class='hs-varid'>biFun</span><span class='hs-layout'>)</span>
<a name="line-286"></a>         <span class='hs-keyglyph'>[</span> <span class='hs-varid'>clause</span> <span class='hs-conid'>[]</span>
<a name="line-287"></a>                  <span class='hs-layout'>(</span><span class='hs-varid'>normalB</span> <span class='hs-varop'>$</span> <span class='hs-varid'>makeBiFunForCons</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>cons</span><span class='hs-layout'>)</span>
<a name="line-288"></a>                  <span class='hs-conid'>[]</span>
<a name="line-289"></a>         <span class='hs-keyglyph'>]</span>
<a name="line-290"></a>
<a name="line-291"></a><a name="makeBiFun"></a><span class='hs-comment'>-- | Generates a lambda expression which behaves like the BiFun argument.</span>
<a name="line-292"></a><span class='hs-definition'>makeBiFun</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-293"></a><span class='hs-definition'>makeBiFun</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>name</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>withType</span> <span class='hs-varid'>name</span> <span class='hs-varid'>fromCons</span> <span class='hs-keyword'>where</span>
<a name="line-294"></a>  <span class='hs-varid'>fromCons</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Cxt</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVarBndr</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Con</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-295"></a>  <span class='hs-varid'>fromCons</span> <span class='hs-varid'>name'</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>cons</span> <span class='hs-varid'>mbTys</span> <span class='hs-keyglyph'>=</span>
<a name="line-296"></a>    <span class='hs-comment'>-- We force buildTypeInstance here since it performs some checks for whether</span>
<a name="line-297"></a>    <span class='hs-comment'>-- or not the provided datatype can actually have bimap/bifoldr/bitraverse/etc.</span>
<a name="line-298"></a>    <span class='hs-comment'>-- implemented for it, and produces errors if it can't.</span>
<a name="line-299"></a>    <span class='hs-varid'>buildTypeInstance</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFunToClass</span> <span class='hs-varid'>biFun</span><span class='hs-layout'>)</span> <span class='hs-varid'>name'</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>mbTys</span>
<a name="line-300"></a>      <span class='hs-varop'>`seq`</span> <span class='hs-varid'>makeBiFunForCons</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>cons</span>
<a name="line-301"></a>
<a name="line-302"></a><a name="makeBiFunForCons"></a><span class='hs-comment'>-- | Generates a lambda expression for the given constructors.</span>
<a name="line-303"></a><span class='hs-comment'>-- All constructors must be from the same type.</span>
<a name="line-304"></a><span class='hs-definition'>makeBiFunForCons</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Con</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-305"></a><span class='hs-definition'>makeBiFunForCons</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>cons</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-306"></a>  <span class='hs-varid'>argNames</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>newName</span> <span class='hs-varop'>$</span> <span class='hs-varid'>catMaybes</span> <span class='hs-keyglyph'>[</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"f"</span>
<a name="line-307"></a>                                       <span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"g"</span>
<a name="line-308"></a>                                       <span class='hs-layout'>,</span> <span class='hs-varid'>guard</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFun</span> <span class='hs-varop'>==</span> <span class='hs-conid'>Bifoldr</span><span class='hs-layout'>)</span> <span class='hs-varop'>&gt;&gt;</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"z"</span>
<a name="line-309"></a>                                       <span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"value"</span>
<a name="line-310"></a>                                       <span class='hs-keyglyph'>]</span>
<a name="line-311"></a>  <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>map1</span><span class='hs-layout'>,</span> <span class='hs-varid'>map2</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-varid'>others</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-num'>2</span> <span class='hs-varid'>argNames</span>
<a name="line-312"></a>      <span class='hs-varid'>z</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>head</span> <span class='hs-varid'>others</span> <span class='hs-comment'>-- If we're deriving bifoldr, this will be well defined</span>
<a name="line-313"></a>                          <span class='hs-comment'>-- and useful. Otherwise, it'll be ignored.</span>
<a name="line-314"></a>      <span class='hs-varid'>value</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>last</span> <span class='hs-varid'>others</span>
<a name="line-315"></a>  <span class='hs-varid'>lamE</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>argNames</span><span class='hs-layout'>)</span>
<a name="line-316"></a>      <span class='hs-varop'>.</span> <span class='hs-varid'>appsE</span>
<a name="line-317"></a>      <span class='hs-varop'>$</span> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>varE</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunConstName</span> <span class='hs-varid'>biFun</span>
<a name="line-318"></a>        <span class='hs-layout'>,</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>null</span> <span class='hs-varid'>cons</span>
<a name="line-319"></a>             <span class='hs-keyword'>then</span> <span class='hs-varid'>appE</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>errorValName</span><span class='hs-layout'>)</span>
<a name="line-320"></a>                       <span class='hs-layout'>(</span><span class='hs-varid'>stringE</span> <span class='hs-varop'>$</span> <span class='hs-str'>"Void "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>nameBase</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFunName</span> <span class='hs-varid'>biFun</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-321"></a>             <span class='hs-keyword'>else</span> <span class='hs-varid'>caseE</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>value</span><span class='hs-layout'>)</span>
<a name="line-322"></a>                        <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>makeBiFunForCon</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>z</span> <span class='hs-varid'>map1</span> <span class='hs-varid'>map2</span><span class='hs-layout'>)</span> <span class='hs-varid'>cons</span><span class='hs-layout'>)</span>
<a name="line-323"></a>        <span class='hs-keyglyph'>]</span> <span class='hs-varop'>++</span> <span class='hs-varid'>map</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>argNames</span>
<a name="line-324"></a>
<a name="line-325"></a><a name="makeBiFunForCon"></a><span class='hs-comment'>-- | Generates a lambda expression for a single constructor.</span>
<a name="line-326"></a><span class='hs-definition'>makeBiFunForCon</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Con</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Match</span>
<a name="line-327"></a><span class='hs-definition'>makeBiFunForCon</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>z</span> <span class='hs-varid'>map1</span> <span class='hs-varid'>map2</span> <span class='hs-varid'>con</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-328"></a>  <span class='hs-keyword'>let</span> <span class='hs-varid'>conName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>constructorName</span> <span class='hs-varid'>con</span>
<a name="line-329"></a>  <span class='hs-layout'>(</span><span class='hs-varid'>ts</span><span class='hs-layout'>,</span> <span class='hs-varid'>tvMap</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>reifyConTys</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>map1</span> <span class='hs-varid'>map2</span>
<a name="line-330"></a>  <span class='hs-varid'>argNames</span>    <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newNameList</span> <span class='hs-str'>"_arg"</span> <span class='hs-varop'>$</span> <span class='hs-varid'>length</span> <span class='hs-varid'>ts</span>
<a name="line-331"></a>  <span class='hs-varid'>makeBiFunForArgs</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>z</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>argNames</span>
<a name="line-332"></a>
<a name="line-333"></a><a name="makeBiFunForArgs"></a><span class='hs-comment'>-- | Generates a lambda expression for a single constructor's arguments.</span>
<a name="line-334"></a><span class='hs-definition'>makeBiFunForArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span>
<a name="line-335"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-336"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>TyVarMap</span>
<a name="line-337"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-338"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-339"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-340"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Match</span>
<a name="line-341"></a><span class='hs-definition'>makeBiFunForArgs</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>z</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>tys</span> <span class='hs-varid'>args</span> <span class='hs-keyglyph'>=</span>
<a name="line-342"></a>  <span class='hs-varid'>match</span> <span class='hs-layout'>(</span><span class='hs-varid'>conP</span> <span class='hs-varid'>conName</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>args</span><span class='hs-layout'>)</span>
<a name="line-343"></a>        <span class='hs-layout'>(</span><span class='hs-varid'>normalB</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunCombine</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>z</span> <span class='hs-varid'>args</span> <span class='hs-varid'>mappedArgs</span><span class='hs-layout'>)</span>
<a name="line-344"></a>        <span class='hs-conid'>[]</span>
<a name="line-345"></a>  <span class='hs-keyword'>where</span>
<a name="line-346"></a>    <span class='hs-varid'>mappedArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-347"></a>    <span class='hs-varid'>mappedArgs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zipWithM</span> <span class='hs-layout'>(</span><span class='hs-varid'>makeBiFunForArg</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span> <span class='hs-varid'>tys</span> <span class='hs-varid'>args</span>
<a name="line-348"></a>
<a name="line-349"></a><a name="makeBiFunForArg"></a><span class='hs-comment'>-- | Generates a lambda expression for a single argument of a constructor.</span>
<a name="line-350"></a><span class='hs-comment'>--  The returned value is 'Right' if its type mentions one of the last two type</span>
<a name="line-351"></a><span class='hs-comment'>-- parameters. Otherwise, it is 'Left'.</span>
<a name="line-352"></a><span class='hs-definition'>makeBiFunForArg</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span>
<a name="line-353"></a>                <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>TyVarMap</span>
<a name="line-354"></a>                <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-355"></a>                <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span>
<a name="line-356"></a>                <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-357"></a>                <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-layout'>)</span>
<a name="line-358"></a><span class='hs-definition'>makeBiFunForArg</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>ty</span> <span class='hs-varid'>tyExpName</span> <span class='hs-keyglyph'>=</span>
<a name="line-359"></a>  <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-conid'>True</span> <span class='hs-varid'>ty</span> <span class='hs-varop'>`appEitherE`</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>tyExpName</span>
<a name="line-360"></a>
<a name="line-361"></a><a name="makeBiFunForType"></a><span class='hs-comment'>-- | Generates a lambda expression for a specific type. The returned value is</span>
<a name="line-362"></a><span class='hs-comment'>-- 'Right' if its type mentions one of the last two type parameters. Otherwise,</span>
<a name="line-363"></a><span class='hs-comment'>-- it is 'Left'.</span>
<a name="line-364"></a><span class='hs-definition'>makeBiFunForType</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span>
<a name="line-365"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>TyVarMap</span>
<a name="line-366"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-367"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Bool</span>
<a name="line-368"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span>
<a name="line-369"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-layout'>)</span>
<a name="line-370"></a><span class='hs-definition'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarT</span> <span class='hs-varid'>tyName</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-371"></a>  <span class='hs-keyword'>case</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>tyName</span> <span class='hs-varid'>tvMap</span> <span class='hs-keyword'>of</span>
<a name="line-372"></a>    <span class='hs-conid'>Just</span> <span class='hs-varid'>mapName</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>fmap</span> <span class='hs-conid'>Right</span> <span class='hs-varop'>.</span> <span class='hs-varid'>varE</span> <span class='hs-varop'>$</span>
<a name="line-373"></a>                        <span class='hs-keyword'>if</span> <span class='hs-varid'>covariant</span>
<a name="line-374"></a>                           <span class='hs-keyword'>then</span> <span class='hs-varid'>mapName</span>
<a name="line-375"></a>                           <span class='hs-keyword'>else</span> <span class='hs-varid'>contravarianceError</span> <span class='hs-varid'>conName</span>
<a name="line-376"></a>    <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>fmap</span> <span class='hs-conid'>Left</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunTriv</span> <span class='hs-varid'>biFun</span>
<a name="line-377"></a><span class='hs-definition'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-layout'>(</span><span class='hs-conid'>SigT</span> <span class='hs-varid'>ty</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-378"></a>  <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-varid'>ty</span>
<a name="line-379"></a><span class='hs-definition'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-layout'>(</span><span class='hs-conid'>ForallT</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-380"></a>  <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-varid'>ty</span>
<a name="line-381"></a><span class='hs-definition'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-varid'>ty</span> <span class='hs-keyglyph'>=</span>
<a name="line-382"></a>  <span class='hs-keyword'>let</span> <span class='hs-varid'>tyCon</span>  <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Type</span>
<a name="line-383"></a>      <span class='hs-varid'>tyArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-384"></a>      <span class='hs-varid'>tyCon</span><span class='hs-conop'>:</span><span class='hs-varid'>tyArgs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unapplyTy</span> <span class='hs-varid'>ty</span>
<a name="line-385"></a>
<a name="line-386"></a>      <span class='hs-varid'>numLastArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-387"></a>      <span class='hs-varid'>numLastArgs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>min</span> <span class='hs-num'>2</span> <span class='hs-varop'>$</span> <span class='hs-varid'>length</span> <span class='hs-varid'>tyArgs</span>
<a name="line-388"></a>
<a name="line-389"></a>      <span class='hs-varid'>lhsArgs</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhsArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-390"></a>      <span class='hs-layout'>(</span><span class='hs-varid'>lhsArgs</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhsArgs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>tyArgs</span> <span class='hs-comment'>-</span> <span class='hs-varid'>numLastArgs</span><span class='hs-layout'>)</span> <span class='hs-varid'>tyArgs</span>
<a name="line-391"></a>
<a name="line-392"></a>      <span class='hs-varid'>tyVarNames</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-393"></a>      <span class='hs-varid'>tyVarNames</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>keys</span> <span class='hs-varid'>tvMap</span>
<a name="line-394"></a>
<a name="line-395"></a>      <span class='hs-varid'>mentionsTyArgs</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span>
<a name="line-396"></a>      <span class='hs-varid'>mentionsTyArgs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`mentionsName`</span> <span class='hs-varid'>tyVarNames</span><span class='hs-layout'>)</span> <span class='hs-varid'>tyArgs</span>
<a name="line-397"></a>
<a name="line-398"></a>      <span class='hs-varid'>makeBiFunTuple</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Q</span> <span class='hs-conid'>Pat</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Pat</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Int</span>
<a name="line-399"></a>                     <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-layout'>)</span>
<a name="line-400"></a>      <span class='hs-varid'>makeBiFunTuple</span> <span class='hs-varid'>mkTupP</span> <span class='hs-varid'>mkTupleDataName</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-401"></a>        <span class='hs-varid'>args</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>newName</span> <span class='hs-varop'>$</span> <span class='hs-varid'>catMaybes</span> <span class='hs-keyglyph'>[</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"x"</span>
<a name="line-402"></a>                                         <span class='hs-layout'>,</span> <span class='hs-varid'>guard</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFun</span> <span class='hs-varop'>==</span> <span class='hs-conid'>Bifoldr</span><span class='hs-layout'>)</span> <span class='hs-varop'>&gt;&gt;</span> <span class='hs-conid'>Just</span> <span class='hs-str'>"z"</span>
<a name="line-403"></a>                                         <span class='hs-keyglyph'>]</span>
<a name="line-404"></a>        <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newNameList</span> <span class='hs-str'>"_tup"</span> <span class='hs-varid'>n</span>
<a name="line-405"></a>
<a name="line-406"></a>        <span class='hs-keyword'>let</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>head</span> <span class='hs-varid'>args</span>
<a name="line-407"></a>            <span class='hs-varid'>z</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>last</span> <span class='hs-varid'>args</span>
<a name="line-408"></a>        <span class='hs-varid'>fmap</span> <span class='hs-conid'>Right</span> <span class='hs-varop'>$</span> <span class='hs-varid'>lamE</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>args</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>caseE</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-409"></a>             <span class='hs-keyglyph'>[</span> <span class='hs-varid'>match</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkTupP</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-410"></a>                     <span class='hs-layout'>(</span><span class='hs-varid'>normalB</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunCombine</span> <span class='hs-varid'>biFun</span>
<a name="line-411"></a>                                             <span class='hs-layout'>(</span><span class='hs-varid'>mkTupleDataName</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span>
<a name="line-412"></a>                                             <span class='hs-varid'>z</span>
<a name="line-413"></a>                                             <span class='hs-varid'>xs</span>
<a name="line-414"></a>                                             <span class='hs-layout'>(</span><span class='hs-varid'>zipWithM</span> <span class='hs-varid'>makeBiFunTupleField</span> <span class='hs-varid'>tyArgs</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-415"></a>                     <span class='hs-layout'>)</span>
<a name="line-416"></a>                     <span class='hs-conid'>[]</span>
<a name="line-417"></a>             <span class='hs-keyglyph'>]</span>
<a name="line-418"></a>
<a name="line-419"></a>      <span class='hs-varid'>makeBiFunTupleField</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-layout'>)</span>
<a name="line-420"></a>      <span class='hs-varid'>makeBiFunTupleField</span> <span class='hs-varid'>fieldTy</span> <span class='hs-varid'>fieldName</span> <span class='hs-keyglyph'>=</span>
<a name="line-421"></a>        <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span> <span class='hs-varid'>fieldTy</span>
<a name="line-422"></a>          <span class='hs-varop'>`appEitherE`</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>fieldName</span>
<a name="line-423"></a>
<a name="line-424"></a>   <span class='hs-keyword'>in</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>tyCon</span> <span class='hs-keyword'>of</span>
<a name="line-425"></a>     <span class='hs-conid'>ArrowT</span>
<a name="line-426"></a>       <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>allowFunTys</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFunToClass</span> <span class='hs-varid'>biFun</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>noFunctionsError</span> <span class='hs-varid'>conName</span>
<a name="line-427"></a>       <span class='hs-keyglyph'>|</span> <span class='hs-varid'>mentionsTyArgs</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>argTy</span><span class='hs-layout'>,</span> <span class='hs-varid'>resTy</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>tyArgs</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-428"></a>         <span class='hs-keyword'>do</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"x"</span>
<a name="line-429"></a>            <span class='hs-varid'>b</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"b"</span>
<a name="line-430"></a>            <span class='hs-varid'>fmap</span> <span class='hs-conid'>Right</span> <span class='hs-varop'>.</span> <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>varP</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span>
<a name="line-431"></a>              <span class='hs-varid'>covBiFun</span> <span class='hs-varid'>covariant</span> <span class='hs-varid'>resTy</span> <span class='hs-varop'>`appE`</span> <span class='hs-layout'>(</span><span class='hs-varid'>varE</span> <span class='hs-varid'>x</span> <span class='hs-varop'>`appE`</span>
<a name="line-432"></a>                <span class='hs-layout'>(</span><span class='hs-varid'>covBiFun</span> <span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varid'>covariant</span><span class='hs-layout'>)</span> <span class='hs-varid'>argTy</span> <span class='hs-varop'>`appE`</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-433"></a>         <span class='hs-keyword'>where</span>
<a name="line-434"></a>           <span class='hs-varid'>covBiFun</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Bool</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-435"></a>           <span class='hs-varid'>covBiFun</span> <span class='hs-varid'>cov</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>fromEither</span> <span class='hs-varop'>.</span> <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>cov</span>
<a name="line-436"></a><span class='hs-cpp'>#if MIN_VERSION_template_haskell(2,6,0)</span>
<a name="line-437"></a>     <span class='hs-conid'>UnboxedTupleT</span> <span class='hs-varid'>n</span>
<a name="line-438"></a>       <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'>&gt;</span> <span class='hs-num'>0</span> <span class='hs-varop'>&amp;&amp;</span> <span class='hs-varid'>mentionsTyArgs</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>makeBiFunTuple</span> <span class='hs-varid'>unboxedTupP</span> <span class='hs-varid'>unboxedTupleDataName</span> <span class='hs-varid'>n</span>
<a name="line-439"></a><span class='hs-cpp'>#endif</span>
<a name="line-440"></a>     <span class='hs-conid'>TupleT</span> <span class='hs-varid'>n</span>
<a name="line-441"></a>       <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'>&gt;</span> <span class='hs-num'>0</span> <span class='hs-varop'>&amp;&amp;</span> <span class='hs-varid'>mentionsTyArgs</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>makeBiFunTuple</span> <span class='hs-varid'>tupP</span> <span class='hs-varid'>tupleDataName</span> <span class='hs-varid'>n</span>
<a name="line-442"></a>     <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>do</span>
<a name="line-443"></a>         <span class='hs-varid'>itf</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>isTyFamily</span> <span class='hs-varid'>tyCon</span>
<a name="line-444"></a>         <span class='hs-keyword'>if</span> <span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`mentionsName`</span> <span class='hs-varid'>tyVarNames</span><span class='hs-layout'>)</span> <span class='hs-varid'>lhsArgs</span> <span class='hs-varop'>||</span> <span class='hs-layout'>(</span><span class='hs-varid'>itf</span> <span class='hs-varop'>&amp;&amp;</span> <span class='hs-varid'>mentionsTyArgs</span><span class='hs-layout'>)</span>
<a name="line-445"></a>           <span class='hs-keyword'>then</span> <span class='hs-varid'>outOfPlaceTyVarError</span> <span class='hs-varid'>conName</span>
<a name="line-446"></a>           <span class='hs-keyword'>else</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`mentionsName`</span> <span class='hs-varid'>tyVarNames</span><span class='hs-layout'>)</span> <span class='hs-varid'>rhsArgs</span>
<a name="line-447"></a>                  <span class='hs-keyword'>then</span> <span class='hs-varid'>fmap</span> <span class='hs-conid'>Right</span> <span class='hs-varop'>.</span> <span class='hs-varid'>biFunApp</span> <span class='hs-varid'>biFun</span> <span class='hs-varop'>.</span> <span class='hs-varid'>appsE</span> <span class='hs-varop'>$</span>
<a name="line-448"></a>                         <span class='hs-layout'>(</span> <span class='hs-varid'>varE</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromJust</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunArity</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>numLastArgs</span><span class='hs-layout'>)</span>
<a name="line-449"></a>                         <span class='hs-conop'>:</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>fromEither</span> <span class='hs-varop'>.</span> <span class='hs-varid'>makeBiFunForType</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>tvMap</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>covariant</span><span class='hs-layout'>)</span>
<a name="line-450"></a>                                <span class='hs-varid'>rhsArgs</span>
<a name="line-451"></a>                         <span class='hs-layout'>)</span>
<a name="line-452"></a>                  <span class='hs-keyword'>else</span> <span class='hs-varid'>fmap</span> <span class='hs-conid'>Left</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunTriv</span> <span class='hs-varid'>biFun</span>
<a name="line-453"></a>
<a name="line-454"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-455"></a><span class='hs-comment'>-- Template Haskell reifying and AST manipulation</span>
<a name="line-456"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-457"></a>
<a name="line-458"></a><a name="withType"></a><span class='hs-comment'>-- | Boilerplate for top level splices.</span>
<a name="line-459"></a><span class='hs-comment'>--</span>
<a name="line-460"></a><span class='hs-comment'>-- The given Name must meet one of two criteria:</span>
<a name="line-461"></a><span class='hs-comment'>--</span>
<a name="line-462"></a><span class='hs-comment'>-- 1. It must be the name of a type constructor of a plain data type or newtype.</span>
<a name="line-463"></a><span class='hs-comment'>-- 2. It must be the name of a data family instance or newtype instance constructor.</span>
<a name="line-464"></a><span class='hs-comment'>--</span>
<a name="line-465"></a><span class='hs-comment'>-- Any other value will result in an exception.</span>
<a name="line-466"></a><span class='hs-definition'>withType</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-467"></a>         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Cxt</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVarBndr</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Con</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-468"></a>         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-varid'>a</span>
<a name="line-469"></a><span class='hs-definition'>withType</span> <span class='hs-varid'>name</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-470"></a>  <span class='hs-varid'>info</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>reify</span> <span class='hs-varid'>name</span>
<a name="line-471"></a>  <span class='hs-keyword'>case</span> <span class='hs-varid'>info</span> <span class='hs-keyword'>of</span>
<a name="line-472"></a>    <span class='hs-conid'>TyConI</span> <span class='hs-varid'>dec</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-473"></a>      <span class='hs-keyword'>case</span> <span class='hs-varid'>dec</span> <span class='hs-keyword'>of</span>
<a name="line-474"></a>        <span class='hs-conid'>DataD</span> <span class='hs-varid'>ctxt</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>tvbs</span>
<a name="line-475"></a><span class='hs-cpp'>#if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-476"></a>              <span class='hs-keyword'>_</span>
<a name="line-477"></a><span class='hs-cpp'>#endif</span>
<a name="line-478"></a>              <span class='hs-varid'>cons</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varid'>name</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>cons</span> <span class='hs-conid'>Nothing</span>
<a name="line-479"></a>        <span class='hs-conid'>NewtypeD</span> <span class='hs-varid'>ctxt</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>tvbs</span>
<a name="line-480"></a><span class='hs-cpp'>#if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-481"></a>                 <span class='hs-keyword'>_</span>
<a name="line-482"></a><span class='hs-cpp'>#endif</span>
<a name="line-483"></a>                 <span class='hs-varid'>con</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varid'>name</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>con</span><span class='hs-keyglyph'>]</span> <span class='hs-conid'>Nothing</span>
<a name="line-484"></a>        <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span> <span class='hs-str'>"Unsupported type: "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>show</span> <span class='hs-varid'>dec</span>
<a name="line-485"></a><span class='hs-cpp'>#if MIN_VERSION_template_haskell(2,7,0)</span>
<a name="line-486"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-487"></a>    <span class='hs-conid'>DataConI</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>parentName</span>   <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>do</span>
<a name="line-488"></a><span class='hs-cpp'># else</span>
<a name="line-489"></a>    <span class='hs-conid'>DataConI</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>parentName</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>do</span>
<a name="line-490"></a><span class='hs-cpp'># endif</span>
<a name="line-491"></a>      <span class='hs-varid'>parentInfo</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>reify</span> <span class='hs-varid'>parentName</span>
<a name="line-492"></a>      <span class='hs-keyword'>case</span> <span class='hs-varid'>parentInfo</span> <span class='hs-keyword'>of</span>
<a name="line-493"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-494"></a>        <span class='hs-conid'>FamilyI</span> <span class='hs-layout'>(</span><span class='hs-conid'>DataFamilyD</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>tvbs</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>decs</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-495"></a><span class='hs-cpp'># else</span>
<a name="line-496"></a>        <span class='hs-conid'>FamilyI</span> <span class='hs-layout'>(</span><span class='hs-conid'>FamilyD</span> <span class='hs-conid'>DataFam</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>tvbs</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>decs</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-497"></a><span class='hs-cpp'># endif</span>
<a name="line-498"></a>          <span class='hs-keyword'>let</span> <span class='hs-varid'>instDec</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>flip</span> <span class='hs-varid'>find</span> <span class='hs-varid'>decs</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>dec</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>dec</span> <span class='hs-keyword'>of</span>
<a name="line-499"></a>                <span class='hs-conid'>DataInstD</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span>
<a name="line-500"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-501"></a>                          <span class='hs-keyword'>_</span>
<a name="line-502"></a><span class='hs-cpp'># endif</span>
<a name="line-503"></a>                          <span class='hs-varid'>cons</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>name</span> <span class='hs-varop'>==</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>constructorName</span><span class='hs-layout'>)</span> <span class='hs-varid'>cons</span>
<a name="line-504"></a>                <span class='hs-conid'>NewtypeInstD</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span>
<a name="line-505"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-506"></a>                             <span class='hs-keyword'>_</span>
<a name="line-507"></a><span class='hs-cpp'># endif</span>
<a name="line-508"></a>                             <span class='hs-varid'>con</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>name</span> <span class='hs-varop'>==</span> <span class='hs-varid'>constructorName</span> <span class='hs-varid'>con</span>
<a name="line-509"></a>                <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span> <span class='hs-str'>"Must be a data or newtype instance."</span>
<a name="line-510"></a>           <span class='hs-keyword'>in</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>instDec</span> <span class='hs-keyword'>of</span>
<a name="line-511"></a>                <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>DataInstD</span> <span class='hs-varid'>ctxt</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>instTys</span>
<a name="line-512"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-513"></a>                                <span class='hs-keyword'>_</span>
<a name="line-514"></a><span class='hs-cpp'># endif</span>
<a name="line-515"></a>                                <span class='hs-varid'>cons</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-516"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varid'>parentName</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>cons</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>instTys</span>
<a name="line-517"></a>                <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>NewtypeInstD</span> <span class='hs-varid'>ctxt</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>instTys</span>
<a name="line-518"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-519"></a>                                   <span class='hs-keyword'>_</span>
<a name="line-520"></a><span class='hs-cpp'># endif</span>
<a name="line-521"></a>                                   <span class='hs-varid'>con</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-522"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>f</span> <span class='hs-varid'>parentName</span> <span class='hs-varid'>ctxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>con</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>instTys</span>
<a name="line-523"></a>                <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span>
<a name="line-524"></a>                  <span class='hs-str'>"Could not find data or newtype instance constructor."</span>
<a name="line-525"></a>        <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span> <span class='hs-str'>"Data constructor "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>show</span> <span class='hs-varid'>name</span> <span class='hs-varop'>++</span>
<a name="line-526"></a>          <span class='hs-str'>" is not from a data family instance constructor."</span>
<a name="line-527"></a><span class='hs-cpp'># if MIN_VERSION_template_haskell(2,11,0)</span>
<a name="line-528"></a>    <span class='hs-conid'>FamilyI</span> <span class='hs-conid'>DataFamilyD</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-529"></a><span class='hs-cpp'># else</span>
<a name="line-530"></a>    <span class='hs-conid'>FamilyI</span> <span class='hs-layout'>(</span><span class='hs-conid'>FamilyD</span> <span class='hs-conid'>DataFam</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-531"></a><span class='hs-cpp'># endif</span>
<a name="line-532"></a>      <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span>
<a name="line-533"></a>        <span class='hs-str'>"Cannot use a data family name. Use a data family instance constructor instead."</span>
<a name="line-534"></a>    <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span> <span class='hs-str'>"The name must be of a plain data type constructor, "</span>
<a name="line-535"></a>                    <span class='hs-varop'>++</span> <span class='hs-str'>"or a data family instance constructor."</span>
<a name="line-536"></a><span class='hs-cpp'>#else</span>
<a name="line-537"></a>    <span class='hs-conid'>DataConI</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>dataConIError</span>
<a name="line-538"></a>    <span class='hs-keyword'>_</span>          <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ns</span> <span class='hs-varop'>++</span> <span class='hs-str'>"The name must be of a plain type constructor."</span>
<a name="line-539"></a><span class='hs-cpp'>#endif</span>
<a name="line-540"></a>  <span class='hs-keyword'>where</span>
<a name="line-541"></a>    <span class='hs-varid'>ns</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span>
<a name="line-542"></a>    <span class='hs-varid'>ns</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"Data.Bifunctor.TH.withType: "</span>
<a name="line-543"></a>
<a name="line-544"></a><a name="buildTypeInstance"></a><span class='hs-comment'>-- | Deduces the instance context and head for an instance.</span>
<a name="line-545"></a><span class='hs-definition'>buildTypeInstance</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span>
<a name="line-546"></a>                  <span class='hs-comment'>-- ^ Bifunctor, Bifoldable, or Bitraversable</span>
<a name="line-547"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-548"></a>                  <span class='hs-comment'>-- ^ The type constructor or data family name</span>
<a name="line-549"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Cxt</span>
<a name="line-550"></a>                  <span class='hs-comment'>-- ^ The datatype context</span>
<a name="line-551"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>TyVarBndr</span><span class='hs-keyglyph'>]</span>
<a name="line-552"></a>                  <span class='hs-comment'>-- ^ The type variables from the data type/data family declaration</span>
<a name="line-553"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-554"></a>                  <span class='hs-comment'>-- ^ 'Just' the types used to instantiate a data family instance,</span>
<a name="line-555"></a>                  <span class='hs-comment'>-- or 'Nothing' if it's a plain data type</span>
<a name="line-556"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Cxt</span><span class='hs-layout'>,</span> <span class='hs-conid'>Type</span><span class='hs-layout'>)</span>
<a name="line-557"></a><span class='hs-comment'>-- Plain data type/newtype case</span>
<a name="line-558"></a><span class='hs-definition'>buildTypeInstance</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span> <span class='hs-varid'>dataCxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span>
<a name="line-559"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>varTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-560"></a>        <span class='hs-varid'>varTys</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>tvbToType</span> <span class='hs-varid'>tvbs</span>
<a name="line-561"></a>    <span class='hs-keyword'>in</span> <span class='hs-varid'>buildTypeInstanceFromTys</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span> <span class='hs-varid'>dataCxt</span> <span class='hs-varid'>varTys</span> <span class='hs-conid'>False</span>
<a name="line-562"></a><span class='hs-comment'>-- Data family instance case</span>
<a name="line-563"></a><span class='hs-comment'>--</span>
<a name="line-564"></a><span class='hs-comment'>-- The CPP is present to work around a couple of annoying old GHC bugs.</span>
<a name="line-565"></a><span class='hs-comment'>-- See Note [Polykinded data families in Template Haskell]</span>
<a name="line-566"></a><span class='hs-definition'>buildTypeInstance</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>parentName</span> <span class='hs-varid'>dataCxt</span> <span class='hs-varid'>tvbs</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>instTysAndKinds</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-567"></a><span class='hs-cpp'>#if !(MIN_VERSION_template_haskell(2,8,0)) || MIN_VERSION_template_haskell(2,10,0)</span>
<a name="line-568"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>instTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-569"></a>        <span class='hs-varid'>instTys</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>zipWith</span> <span class='hs-varid'>stealKindForType</span> <span class='hs-varid'>tvbs</span> <span class='hs-varid'>instTysAndKinds</span>
<a name="line-570"></a><span class='hs-cpp'>#else</span>
<a name="line-571"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>kindVarNames</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-572"></a>        <span class='hs-varid'>kindVarNames</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nub</span> <span class='hs-varop'>$</span> <span class='hs-varid'>concatMap</span> <span class='hs-layout'>(</span><span class='hs-varid'>tyVarNamesOfType</span> <span class='hs-varop'>.</span> <span class='hs-varid'>tvbKind</span><span class='hs-layout'>)</span> <span class='hs-varid'>tvbs</span>
<a name="line-573"></a>
<a name="line-574"></a>        <span class='hs-varid'>numKindVars</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-575"></a>        <span class='hs-varid'>numKindVars</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>length</span> <span class='hs-varid'>kindVarNames</span>
<a name="line-576"></a>
<a name="line-577"></a>        <span class='hs-varid'>givenKinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>givenKinds'</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Kind</span><span class='hs-keyglyph'>]</span>
<a name="line-578"></a>        <span class='hs-varid'>givenTys</span>                <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-579"></a>        <span class='hs-layout'>(</span><span class='hs-varid'>givenKinds</span><span class='hs-layout'>,</span> <span class='hs-varid'>givenTys</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-varid'>numKindVars</span> <span class='hs-varid'>instTysAndKinds</span>
<a name="line-580"></a>        <span class='hs-varid'>givenKinds'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>sanitizeStars</span> <span class='hs-varid'>givenKinds</span>
<a name="line-581"></a>
<a name="line-582"></a>        <span class='hs-comment'>-- A GHC 7.6-specific bug requires us to replace all occurrences of</span>
<a name="line-583"></a>        <span class='hs-comment'>-- (ConT GHC.Prim.*) with StarT, or else Template Haskell will reject it.</span>
<a name="line-584"></a>        <span class='hs-comment'>-- Luckily, (ConT GHC.Prim.*) only seems to occur in this one spot.</span>
<a name="line-585"></a>        <span class='hs-varid'>sanitizeStars</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Kind</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Kind</span>
<a name="line-586"></a>        <span class='hs-varid'>sanitizeStars</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-587"></a>          <span class='hs-keyword'>where</span>
<a name="line-588"></a>            <span class='hs-varid'>go</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Kind</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Kind</span>
<a name="line-589"></a>            <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>AppT</span> <span class='hs-varid'>t1</span> <span class='hs-varid'>t2</span><span class='hs-layout'>)</span>                 <span class='hs-keyglyph'>=</span> <span class='hs-conid'>AppT</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t2</span><span class='hs-layout'>)</span>
<a name="line-590"></a>            <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>SigT</span> <span class='hs-varid'>t</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>                   <span class='hs-keyglyph'>=</span> <span class='hs-conid'>SigT</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
<a name="line-591"></a>            <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>ConT</span> <span class='hs-varid'>n</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>n</span> <span class='hs-varop'>==</span> <span class='hs-varid'>starKindName</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>StarT</span>
<a name="line-592"></a>            <span class='hs-varid'>go</span> <span class='hs-varid'>t</span>                            <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span>
<a name="line-593"></a>
<a name="line-594"></a>    <span class='hs-comment'>-- If we run this code with GHC 7.8, we might have to generate extra type</span>
<a name="line-595"></a>    <span class='hs-comment'>-- variables to compensate for any type variables that Template Haskell</span>
<a name="line-596"></a>    <span class='hs-comment'>-- eta-reduced away.</span>
<a name="line-597"></a>    <span class='hs-comment'>-- See Note [Polykinded data families in Template Haskell]</span>
<a name="line-598"></a>    <span class='hs-varid'>xTypeNames</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newNameList</span> <span class='hs-str'>"tExtra"</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>tvbs</span> <span class='hs-comment'>-</span> <span class='hs-varid'>length</span> <span class='hs-varid'>givenTys</span><span class='hs-layout'>)</span>
<a name="line-599"></a>
<a name="line-600"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>xTys</span>   <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-601"></a>        <span class='hs-varid'>xTys</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-conid'>VarT</span> <span class='hs-varid'>xTypeNames</span>
<a name="line-602"></a>        <span class='hs-comment'>-- ^ Because these type variables were eta-reduced away, we can only</span>
<a name="line-603"></a>        <span class='hs-comment'>--   determine their kind by using stealKindForType. Therefore, we mark</span>
<a name="line-604"></a>        <span class='hs-comment'>--   them as VarT to ensure they will be given an explicit kind annotation</span>
<a name="line-605"></a>        <span class='hs-comment'>--   (and so the kind inference machinery has the right information).</span>
<a name="line-606"></a>
<a name="line-607"></a>        <span class='hs-varid'>substNamesWithKinds</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Name</span><span class='hs-layout'>,</span> <span class='hs-conid'>Kind</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span>
<a name="line-608"></a>        <span class='hs-varid'>substNamesWithKinds</span> <span class='hs-varid'>nks</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr'</span> <span class='hs-layout'>(</span><span class='hs-varid'>uncurry</span> <span class='hs-varid'>substNameWithKind</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span> <span class='hs-varid'>nks</span>
<a name="line-609"></a>
<a name="line-610"></a>        <span class='hs-comment'>-- The types from the data family instance might not have explicit kind</span>
<a name="line-611"></a>        <span class='hs-comment'>-- annotations, which the kind machinery needs to work correctly. To</span>
<a name="line-612"></a>        <span class='hs-comment'>-- compensate, we use stealKindForType to explicitly annotate any</span>
<a name="line-613"></a>        <span class='hs-comment'>-- types without kind annotations.</span>
<a name="line-614"></a>        <span class='hs-varid'>instTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-615"></a>        <span class='hs-varid'>instTys</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>substNamesWithKinds</span> <span class='hs-layout'>(</span><span class='hs-varid'>zip</span> <span class='hs-varid'>kindVarNames</span> <span class='hs-varid'>givenKinds'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-616"></a>                  <span class='hs-comment'>-- Note that due to a GHC 7.8-specific bug</span>
<a name="line-617"></a>                  <span class='hs-comment'>-- (see Note [Polykinded data families in Template Haskell]),</span>
<a name="line-618"></a>                  <span class='hs-comment'>-- there may be more kind variable names than there are kinds</span>
<a name="line-619"></a>                  <span class='hs-comment'>-- to substitute. But this is OK! If a kind is eta-reduced, it</span>
<a name="line-620"></a>                  <span class='hs-comment'>-- means that is was not instantiated to something more specific,</span>
<a name="line-621"></a>                  <span class='hs-comment'>--   so we need not substitute it. Using stealKindForType will</span>
<a name="line-622"></a>                  <span class='hs-comment'>--   grab the correct kind.</span>
<a name="line-623"></a>                <span class='hs-varop'>$</span> <span class='hs-varid'>zipWith</span> <span class='hs-varid'>stealKindForType</span> <span class='hs-varid'>tvbs</span> <span class='hs-layout'>(</span><span class='hs-varid'>givenTys</span> <span class='hs-varop'>++</span> <span class='hs-varid'>xTys</span><span class='hs-layout'>)</span>
<a name="line-624"></a><span class='hs-cpp'>#endif</span>
<a name="line-625"></a>    <span class='hs-varid'>buildTypeInstanceFromTys</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>parentName</span> <span class='hs-varid'>dataCxt</span> <span class='hs-varid'>instTys</span> <span class='hs-conid'>True</span>
<a name="line-626"></a>
<a name="line-627"></a><a name="buildTypeInstanceFromTys"></a><span class='hs-comment'>-- For the given Types, generate an instance context and head. Coming up with</span>
<a name="line-628"></a><span class='hs-comment'>-- the instance type isn't as simple as dropping the last types, as you need to</span>
<a name="line-629"></a><span class='hs-comment'>-- be wary of kinds being instantiated with *.</span>
<a name="line-630"></a><span class='hs-comment'>-- See Note [Type inference in derived instances]</span>
<a name="line-631"></a><span class='hs-definition'>buildTypeInstanceFromTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span>
<a name="line-632"></a>                         <span class='hs-comment'>-- ^ Bifunctor, Bifoldable, or Bitraversable</span>
<a name="line-633"></a>                         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-634"></a>                         <span class='hs-comment'>-- ^ The type constructor or data family name</span>
<a name="line-635"></a>                         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Cxt</span>
<a name="line-636"></a>                         <span class='hs-comment'>-- ^ The datatype context</span>
<a name="line-637"></a>                         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-638"></a>                         <span class='hs-comment'>-- ^ The types to instantiate the instance with</span>
<a name="line-639"></a>                         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Bool</span>
<a name="line-640"></a>                         <span class='hs-comment'>-- ^ True if it's a data family, False otherwise</span>
<a name="line-641"></a>                         <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Cxt</span><span class='hs-layout'>,</span> <span class='hs-conid'>Type</span><span class='hs-layout'>)</span>
<a name="line-642"></a><span class='hs-definition'>buildTypeInstanceFromTys</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span> <span class='hs-varid'>dataCxt</span> <span class='hs-varid'>varTysOrig</span> <span class='hs-varid'>isDataFamily</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-643"></a>    <span class='hs-comment'>-- Make sure to expand through type/kind synonyms! Otherwise, the</span>
<a name="line-644"></a>    <span class='hs-comment'>-- eta-reduction check might get tripped up over type variables in a</span>
<a name="line-645"></a>    <span class='hs-comment'>-- synonym that are actually dropped.</span>
<a name="line-646"></a>    <span class='hs-comment'>-- (See GHC Trac #11416 for a scenario where this actually happened.)</span>
<a name="line-647"></a>    <span class='hs-varid'>varTysExp</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>expandSyn</span> <span class='hs-varid'>varTysOrig</span>
<a name="line-648"></a>
<a name="line-649"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>remainingLength</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span>
<a name="line-650"></a>        <span class='hs-varid'>remainingLength</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>length</span> <span class='hs-varid'>varTysOrig</span> <span class='hs-comment'>-</span> <span class='hs-num'>2</span>
<a name="line-651"></a>
<a name="line-652"></a>        <span class='hs-varid'>droppedTysExp</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-653"></a>        <span class='hs-varid'>droppedTysExp</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>drop</span> <span class='hs-varid'>remainingLength</span> <span class='hs-varid'>varTysExp</span>
<a name="line-654"></a>
<a name="line-655"></a>        <span class='hs-varid'>droppedStarKindStati</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>StarKindStatus</span><span class='hs-keyglyph'>]</span>
<a name="line-656"></a>        <span class='hs-varid'>droppedStarKindStati</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>canRealizeKindStar</span> <span class='hs-varid'>droppedTysExp</span>
<a name="line-657"></a>
<a name="line-658"></a>    <span class='hs-comment'>-- Check there are enough types to drop and that all of them are either of</span>
<a name="line-659"></a>    <span class='hs-comment'>-- kind * or kind k (for some kind variable k). If not, throw an error.</span>
<a name="line-660"></a>    <span class='hs-varid'>when</span> <span class='hs-layout'>(</span><span class='hs-varid'>remainingLength</span> <span class='hs-varop'>&lt;</span> <span class='hs-num'>0</span> <span class='hs-varop'>||</span> <span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>==</span> <span class='hs-conid'>NotKindStar</span><span class='hs-layout'>)</span> <span class='hs-varid'>droppedStarKindStati</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-661"></a>      <span class='hs-varid'>derivingKindError</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span>
<a name="line-662"></a>
<a name="line-663"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>droppedKindVarNames</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-664"></a>        <span class='hs-varid'>droppedKindVarNames</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>catKindVarNames</span> <span class='hs-varid'>droppedStarKindStati</span>
<a name="line-665"></a>
<a name="line-666"></a>        <span class='hs-comment'>-- Substitute kind * for any dropped kind variables</span>
<a name="line-667"></a>        <span class='hs-varid'>varTysExpSubst</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-668"></a>        <span class='hs-varid'>varTysExpSubst</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>substNamesWithKindStar</span> <span class='hs-varid'>droppedKindVarNames</span><span class='hs-layout'>)</span> <span class='hs-varid'>varTysExp</span>
<a name="line-669"></a>
<a name="line-670"></a>        <span class='hs-varid'>remainingTysExpSubst</span><span class='hs-layout'>,</span> <span class='hs-varid'>droppedTysExpSubst</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-671"></a>        <span class='hs-layout'>(</span><span class='hs-varid'>remainingTysExpSubst</span><span class='hs-layout'>,</span> <span class='hs-varid'>droppedTysExpSubst</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-672"></a>          <span class='hs-varid'>splitAt</span> <span class='hs-varid'>remainingLength</span> <span class='hs-varid'>varTysExpSubst</span>
<a name="line-673"></a>
<a name="line-674"></a>        <span class='hs-comment'>-- All of the type variables mentioned in the dropped types</span>
<a name="line-675"></a>        <span class='hs-comment'>-- (post-synonym expansion)</span>
<a name="line-676"></a>        <span class='hs-varid'>droppedTyVarNames</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-677"></a>        <span class='hs-varid'>droppedTyVarNames</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>tyVarNamesOfType</span> <span class='hs-varid'>droppedTysExpSubst</span>
<a name="line-678"></a>
<a name="line-679"></a>    <span class='hs-comment'>-- If any of the dropped types were polykinded, ensure that they are of kind *</span>
<a name="line-680"></a>    <span class='hs-comment'>-- after substituting * for the dropped kind variables. If not, throw an error.</span>
<a name="line-681"></a>    <span class='hs-varid'>unless</span> <span class='hs-layout'>(</span><span class='hs-varid'>all</span> <span class='hs-varid'>hasKindStar</span> <span class='hs-varid'>droppedTysExpSubst</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-682"></a>      <span class='hs-varid'>derivingKindError</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span>
<a name="line-683"></a>
<a name="line-684"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>preds</span>    <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Maybe</span> <span class='hs-conid'>Pred</span><span class='hs-keyglyph'>]</span>
<a name="line-685"></a>        <span class='hs-varid'>kvNames</span>  <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-686"></a>        <span class='hs-varid'>kvNames'</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-687"></a>        <span class='hs-comment'>-- Derive instance constraints (and any kind variables which are specialized</span>
<a name="line-688"></a>        <span class='hs-comment'>-- to * in those constraints)</span>
<a name="line-689"></a>        <span class='hs-layout'>(</span><span class='hs-varid'>preds</span><span class='hs-layout'>,</span> <span class='hs-varid'>kvNames</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unzip</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>deriveConstraint</span> <span class='hs-varid'>biClass</span><span class='hs-layout'>)</span> <span class='hs-varid'>remainingTysExpSubst</span>
<a name="line-690"></a>        <span class='hs-varid'>kvNames'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>concat</span> <span class='hs-varid'>kvNames</span>
<a name="line-691"></a>
<a name="line-692"></a>        <span class='hs-comment'>-- Substitute the kind variables specialized in the constraints with *</span>
<a name="line-693"></a>        <span class='hs-varid'>remainingTysExpSubst'</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-694"></a>        <span class='hs-varid'>remainingTysExpSubst'</span> <span class='hs-keyglyph'>=</span>
<a name="line-695"></a>          <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>substNamesWithKindStar</span> <span class='hs-varid'>kvNames'</span><span class='hs-layout'>)</span> <span class='hs-varid'>remainingTysExpSubst</span>
<a name="line-696"></a>
<a name="line-697"></a>        <span class='hs-comment'>-- We now substitute all of the specialized-to-* kind variable names with</span>
<a name="line-698"></a>        <span class='hs-comment'>-- *, but in the original types, not the synonym-expanded types. The reason</span>
<a name="line-699"></a>        <span class='hs-comment'>-- we do this is a superficial one: we want the derived instance to resemble</span>
<a name="line-700"></a>        <span class='hs-comment'>-- the datatype written in source code as closely as possible. For example,</span>
<a name="line-701"></a>        <span class='hs-comment'>-- for the following data family instance:</span>
<a name="line-702"></a>        <span class='hs-comment'>--</span>
<a name="line-703"></a>        <span class='hs-comment'>--   data family Fam a</span>
<a name="line-704"></a>        <span class='hs-comment'>--   newtype instance Fam String = Fam String</span>
<a name="line-705"></a>        <span class='hs-comment'>--</span>
<a name="line-706"></a>        <span class='hs-comment'>-- We'd want to generate the instance:</span>
<a name="line-707"></a>        <span class='hs-comment'>--</span>
<a name="line-708"></a>        <span class='hs-comment'>--   instance C (Fam String)</span>
<a name="line-709"></a>        <span class='hs-comment'>--</span>
<a name="line-710"></a>        <span class='hs-comment'>-- Not:</span>
<a name="line-711"></a>        <span class='hs-comment'>--</span>
<a name="line-712"></a>        <span class='hs-comment'>--   instance C (Fam [Char])</span>
<a name="line-713"></a>        <span class='hs-varid'>remainingTysOrigSubst</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-714"></a>        <span class='hs-varid'>remainingTysOrigSubst</span> <span class='hs-keyglyph'>=</span>
<a name="line-715"></a>          <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>substNamesWithKindStar</span> <span class='hs-layout'>(</span><span class='hs-varid'>union</span> <span class='hs-varid'>droppedKindVarNames</span> <span class='hs-varid'>kvNames'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-716"></a>            <span class='hs-varop'>$</span> <span class='hs-varid'>take</span> <span class='hs-varid'>remainingLength</span> <span class='hs-varid'>varTysOrig</span>
<a name="line-717"></a>
<a name="line-718"></a>        <span class='hs-varid'>remainingTysOrigSubst'</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span>
<a name="line-719"></a>        <span class='hs-comment'>-- See Note [Kind signatures in derived instances] for an explanation</span>
<a name="line-720"></a>        <span class='hs-comment'>-- of the isDataFamily check.</span>
<a name="line-721"></a>        <span class='hs-varid'>remainingTysOrigSubst'</span> <span class='hs-keyglyph'>=</span>
<a name="line-722"></a>          <span class='hs-keyword'>if</span> <span class='hs-varid'>isDataFamily</span>
<a name="line-723"></a>             <span class='hs-keyword'>then</span> <span class='hs-varid'>remainingTysOrigSubst</span>
<a name="line-724"></a>             <span class='hs-keyword'>else</span> <span class='hs-varid'>map</span> <span class='hs-varid'>unSigT</span> <span class='hs-varid'>remainingTysOrigSubst</span>
<a name="line-725"></a>
<a name="line-726"></a>        <span class='hs-varid'>instanceCxt</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Cxt</span>
<a name="line-727"></a>        <span class='hs-varid'>instanceCxt</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>catMaybes</span> <span class='hs-varid'>preds</span>
<a name="line-728"></a>
<a name="line-729"></a>        <span class='hs-varid'>instanceType</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Type</span>
<a name="line-730"></a>        <span class='hs-varid'>instanceType</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>AppT</span> <span class='hs-layout'>(</span><span class='hs-conid'>ConT</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biClassName</span> <span class='hs-varid'>biClass</span><span class='hs-layout'>)</span>
<a name="line-731"></a>                     <span class='hs-varop'>$</span> <span class='hs-varid'>applyTyCon</span> <span class='hs-varid'>tyConName</span> <span class='hs-varid'>remainingTysOrigSubst'</span>
<a name="line-732"></a>
<a name="line-733"></a>    <span class='hs-comment'>-- If the datatype context mentions any of the dropped type variables,</span>
<a name="line-734"></a>    <span class='hs-comment'>-- we can't derive an instance, so throw an error.</span>
<a name="line-735"></a>    <span class='hs-varid'>when</span> <span class='hs-layout'>(</span><span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`predMentionsName`</span> <span class='hs-varid'>droppedTyVarNames</span><span class='hs-layout'>)</span> <span class='hs-varid'>dataCxt</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-736"></a>      <span class='hs-varid'>datatypeContextError</span> <span class='hs-varid'>tyConName</span> <span class='hs-varid'>instanceType</span>
<a name="line-737"></a>    <span class='hs-comment'>-- Also ensure the dropped types can be safely eta-reduced. Otherwise,</span>
<a name="line-738"></a>    <span class='hs-comment'>-- throw an error.</span>
<a name="line-739"></a>    <span class='hs-varid'>unless</span> <span class='hs-layout'>(</span><span class='hs-varid'>canEtaReduce</span> <span class='hs-varid'>remainingTysExpSubst'</span> <span class='hs-varid'>droppedTysExpSubst</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-740"></a>      <span class='hs-varid'>etaReductionError</span> <span class='hs-varid'>instanceType</span>
<a name="line-741"></a>    <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>instanceCxt</span><span class='hs-layout'>,</span> <span class='hs-varid'>instanceType</span><span class='hs-layout'>)</span>
<a name="line-742"></a>
<a name="line-743"></a><a name="deriveConstraint"></a><span class='hs-comment'>-- | Attempt to derive a constraint on a Type. If successful, return</span>
<a name="line-744"></a><span class='hs-comment'>-- Just the constraint and any kind variable names constrained to *.</span>
<a name="line-745"></a><span class='hs-comment'>-- Otherwise, return Nothing and the empty list.</span>
<a name="line-746"></a><span class='hs-comment'>--</span>
<a name="line-747"></a><span class='hs-comment'>-- See Note [Type inference in derived instances] for the heuristics used to</span>
<a name="line-748"></a><span class='hs-comment'>-- come up with constraints.</span>
<a name="line-749"></a><span class='hs-definition'>deriveConstraint</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-conid'>Pred</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-750"></a><span class='hs-definition'>deriveConstraint</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>t</span>
<a name="line-751"></a>  <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>isTyVar</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-752"></a>  <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>hasKindVarChain</span> <span class='hs-num'>1</span> <span class='hs-varid'>t</span> <span class='hs-keyword'>of</span>
<a name="line-753"></a>      <span class='hs-conid'>Just</span> <span class='hs-varid'>ns</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>`applyClass`</span> <span class='hs-varid'>tName</span><span class='hs-layout'>)</span> <span class='hs-varop'>`fmap`</span> <span class='hs-varid'>biClassConstraint</span> <span class='hs-varid'>biClass</span> <span class='hs-num'>1</span><span class='hs-layout'>,</span> <span class='hs-varid'>ns</span><span class='hs-layout'>)</span>
<a name="line-754"></a>      <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>hasKindVarChain</span> <span class='hs-num'>2</span> <span class='hs-varid'>t</span> <span class='hs-keyword'>of</span>
<a name="line-755"></a>                <span class='hs-conid'>Just</span> <span class='hs-varid'>ns</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>`applyClass`</span> <span class='hs-varid'>tName</span><span class='hs-layout'>)</span> <span class='hs-varop'>`fmap`</span> <span class='hs-varid'>biClassConstraint</span> <span class='hs-varid'>biClass</span> <span class='hs-num'>2</span><span class='hs-layout'>,</span> <span class='hs-varid'>ns</span><span class='hs-layout'>)</span>
<a name="line-756"></a>                <span class='hs-keyword'>_</span>       <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-conid'>Nothing</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-757"></a>  <span class='hs-keyword'>where</span>
<a name="line-758"></a>    <span class='hs-varid'>tName</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-759"></a>    <span class='hs-varid'>tName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>varTToName</span> <span class='hs-varid'>t</span>
<a name="line-760"></a>
<a name="line-761"></a><span class='hs-comment'>{-
<a name="line-762"></a>Note [Polykinded data families in Template Haskell]
<a name="line-763"></a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<a name="line-764"></a>
<a name="line-765"></a>In order to come up with the correct instance context and head for an instance, e.g.,
<a name="line-766"></a>
<a name="line-767"></a>  instance C a =&gt; C (Data a) where ...
<a name="line-768"></a>
<a name="line-769"></a>We need to know the exact types and kinds used to instantiate the instance. For
<a name="line-770"></a>plain old datatypes, this is simple: every type must be a type variable, and
<a name="line-771"></a>Template Haskell reliably tells us the type variables and their kinds.
<a name="line-772"></a>
<a name="line-773"></a>Doing the same for data families proves to be much harder for three reasons:
<a name="line-774"></a>
<a name="line-775"></a>1. On any version of Template Haskell, it may not tell you what an instantiated
<a name="line-776"></a>   type's kind is. For instance, in the following data family instance:
<a name="line-777"></a>
<a name="line-778"></a>     data family Fam (f :: * -&gt; *) (a :: *)
<a name="line-779"></a>     data instance Fam f a
<a name="line-780"></a>
<a name="line-781"></a>   Then if we use TH's reify function, it would tell us the TyVarBndrs of the
<a name="line-782"></a>   data family declaration are:
<a name="line-783"></a>
<a name="line-784"></a>     [KindedTV f (AppT (AppT ArrowT StarT) StarT),KindedTV a StarT]
<a name="line-785"></a>
<a name="line-786"></a>   and the instantiated types of the data family instance are:
<a name="line-787"></a>
<a name="line-788"></a>     [VarT f1,VarT a1]
<a name="line-789"></a>
<a name="line-790"></a>   We can't just pass [VarT f1,VarT a1] to buildTypeInstanceFromTys, since we
<a name="line-791"></a>   have no way of knowing their kinds. Luckily, the TyVarBndrs tell us what the
<a name="line-792"></a>   kind is in case an instantiated type isn't a SigT, so we use the stealKindForType
<a name="line-793"></a>   function to ensure all of the instantiated types are SigTs before passing them
<a name="line-794"></a>   to buildTypeInstanceFromTys.
<a name="line-795"></a>2. On GHC 7.6 and 7.8, a bug is present in which Template Haskell lists all of
<a name="line-796"></a>   the specified kinds of a data family instance efore any of the instantiated
<a name="line-797"></a>   types. Fortunately, this is easy to deal with: you simply count the number of
<a name="line-798"></a>   distinct kind variables in the data family declaration, take that many elements
<a name="line-799"></a>   from the front of the  Types list of the data family instance, substitute the
<a name="line-800"></a>   kind variables with their respective instantiated kinds (which you took earlier),
<a name="line-801"></a>   and proceed as normal.
<a name="line-802"></a>3. On GHC 7.8, an even uglier bug is present (GHC Trac #9692) in which Template
<a name="line-803"></a>   Haskell might not even list all of the Types of a data family instance, since
<a name="line-804"></a>   they are eta-reduced away! And yes, kinds can be eta-reduced too.
<a name="line-805"></a>
<a name="line-806"></a>   The simplest workaround is to count how many instantiated types are missing from
<a name="line-807"></a>   the list and generate extra type variables to use in their place. Luckily, we
<a name="line-808"></a>   needn't worry much if its kind was eta-reduced away, since using stealKindForType
<a name="line-809"></a>   will get it back.
<a name="line-810"></a>
<a name="line-811"></a>Note [Kind signatures in derived instances]
<a name="line-812"></a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<a name="line-813"></a>
<a name="line-814"></a>It is possible to put explicit kind signatures into the derived instances, e.g.,
<a name="line-815"></a>
<a name="line-816"></a>  instance C a =&gt; C (Data (f :: * -&gt; *)) where ...
<a name="line-817"></a>
<a name="line-818"></a>But it is preferable to avoid this if possible. If we come up with an incorrect
<a name="line-819"></a>kind signature (which is entirely possible, since our type inferencer is pretty
<a name="line-820"></a>unsophisticated - see Note [Type inference in derived instances]), then GHC will
<a name="line-821"></a>flat-out reject the instance, which is quite unfortunate.
<a name="line-822"></a>
<a name="line-823"></a>Plain old datatypes have the advantage that you can avoid using any kind signatures
<a name="line-824"></a>at all in their instances. This is because a datatype declaration uses all type
<a name="line-825"></a>variables, so the types that we use in a derived instance uniquely determine their
<a name="line-826"></a>kinds. As long as we plug in the right types, the kind inferencer can do the rest
<a name="line-827"></a>of the work. For this reason, we use unSigT to remove all kind signatures before
<a name="line-828"></a>splicing in the instance context and head.
<a name="line-829"></a>
<a name="line-830"></a>Data family instances are trickier, since a data family can have two instances that
<a name="line-831"></a>are distinguished by kind alone, e.g.,
<a name="line-832"></a>
<a name="line-833"></a>  data family Fam (a :: k)
<a name="line-834"></a>  data instance Fam (a :: * -&gt; *)
<a name="line-835"></a>  data instance Fam (a :: *)
<a name="line-836"></a>
<a name="line-837"></a>If we dropped the kind signatures for C (Fam a), then GHC will have no way of
<a name="line-838"></a>knowing which instance we are talking about. To avoid this scenario, we always
<a name="line-839"></a>include explicit kind signatures in data family instances. There is a chance that
<a name="line-840"></a>the inferred kind signatures will be incorrect, but if so, we can always fall back
<a name="line-841"></a>on the make- functions.
<a name="line-842"></a>
<a name="line-843"></a>Note [Type inference in derived instances]
<a name="line-844"></a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<a name="line-845"></a>
<a name="line-846"></a>Type inference is can be tricky to get right, and we want to avoid recreating the
<a name="line-847"></a>entirety of GHC's type inferencer in Template Haskell. For this reason, we will
<a name="line-848"></a>probably never come up with derived instance contexts that are as accurate as
<a name="line-849"></a>GHC's. But that doesn't mean we can't do anything! There are a couple of simple
<a name="line-850"></a>things we can do to make instance contexts that work for 80% of use cases:
<a name="line-851"></a>
<a name="line-852"></a>1. If one of the last type parameters is polykinded, then its kind will be
<a name="line-853"></a>   specialized to * in the derived instance. We note what kind variable the type
<a name="line-854"></a>   parameter had and substitute it with * in the other types as well. For example,
<a name="line-855"></a>   imagine you had
<a name="line-856"></a>
<a name="line-857"></a>     data Data (a :: k) (b :: k) (c :: k)
<a name="line-858"></a>
<a name="line-859"></a>   Then you'd want to derived instance to be:
<a name="line-860"></a>
<a name="line-861"></a>     instance C (Data (a :: *))
<a name="line-862"></a>
<a name="line-863"></a>   Not:
<a name="line-864"></a>
<a name="line-865"></a>     instance C (Data (a :: k))
<a name="line-866"></a>
<a name="line-867"></a>2. We naïvely come up with instance constraints using the following criteria:
<a name="line-868"></a>
<a name="line-869"></a>   (i)  If there's a type parameter n of kind k1 -&gt; k2 (where k1/k2 are * or kind
<a name="line-870"></a>        variables), then generate a Functor n constraint, and if k1/k2 are kind
<a name="line-871"></a>        variables, then substitute k1/k2 with * elsewhere in the types. We must
<a name="line-872"></a>        consider the case where they are kind variables because you might have a
<a name="line-873"></a>        scenario like this:
<a name="line-874"></a>
<a name="line-875"></a>          newtype Compose (f :: k3 -&gt; *) (g :: k1 -&gt; k2 -&gt; k3) (a :: k1) (b :: k2)
<a name="line-876"></a>            = Compose (f (g a b))
<a name="line-877"></a>
<a name="line-878"></a>        Which would have a derived Bifunctor instance of:
<a name="line-879"></a>
<a name="line-880"></a>          instance (Functor f, Bifunctor g) =&gt; Bifunctor (Compose f g) where ...
<a name="line-881"></a>   (ii) If there's a type parameter n of kind k1 -&gt; k2 -&gt; k3 (where k1/k2/k3 are
<a name="line-882"></a>        * or kind variables), then generate a Bifunctor n constraint and perform
<a name="line-883"></a>        kind substitution as in the other case.
<a name="line-884"></a>-}</span>
<a name="line-885"></a>
<a name="line-886"></a><a name="reifyConTys"></a><span class='hs-comment'>-- Determines the types of a constructor's arguments as well as the last type</span>
<a name="line-887"></a><span class='hs-comment'>-- parameters (along with their map functions), expanding through any type synonyms.</span>
<a name="line-888"></a><span class='hs-comment'>-- The type parameters are determined on a constructor-by-constructor basis since</span>
<a name="line-889"></a><span class='hs-comment'>-- they may be refined to be particular types in a GADT.</span>
<a name="line-890"></a><span class='hs-definition'>reifyConTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span>
<a name="line-891"></a>            <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-892"></a>            <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-893"></a>            <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-894"></a>            <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Type</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>TyVarMap</span><span class='hs-layout'>)</span>
<a name="line-895"></a><span class='hs-definition'>reifyConTys</span> <span class='hs-varid'>biFun</span> <span class='hs-varid'>conName</span> <span class='hs-varid'>map1</span> <span class='hs-varid'>map2</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-896"></a>    <span class='hs-varid'>info</span>          <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>reify</span> <span class='hs-varid'>conName</span>
<a name="line-897"></a>    <span class='hs-layout'>(</span><span class='hs-varid'>ctxt</span><span class='hs-layout'>,</span> <span class='hs-varid'>uncTy</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>info</span> <span class='hs-keyword'>of</span>
<a name="line-898"></a>        <span class='hs-conid'>DataConI</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>ty</span> <span class='hs-keyword'>_</span>
<a name="line-899"></a><span class='hs-cpp'>#if !(MIN_VERSION_template_haskell(2,11,0))</span>
<a name="line-900"></a>                 <span class='hs-keyword'>_</span>
<a name="line-901"></a><span class='hs-cpp'>#endif</span>
<a name="line-902"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>uncurryTy</span> <span class='hs-layout'>(</span><span class='hs-varid'>expandSyn</span> <span class='hs-varid'>ty</span><span class='hs-layout'>)</span>
<a name="line-903"></a>        <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>error</span> <span class='hs-str'>"Must be a data constructor"</span>
<a name="line-904"></a>    <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>argTys</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>resTy</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>uncTy</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>uncTy</span>
<a name="line-905"></a>        <span class='hs-varid'>unapResTy</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unapplyTy</span> <span class='hs-varid'>resTy</span>
<a name="line-906"></a>        <span class='hs-comment'>-- If one of the last type variables is refined to a particular type</span>
<a name="line-907"></a>        <span class='hs-comment'>-- (i.e., not truly polymorphic), we mark it with Nothing and filter</span>
<a name="line-908"></a>        <span class='hs-comment'>-- it out later, since we only apply map functions to arguments of</span>
<a name="line-909"></a>        <span class='hs-comment'>-- a type that it (1) one of the last type variables, and (2)</span>
<a name="line-910"></a>        <span class='hs-comment'>-- of a truly polymorphic type.</span>
<a name="line-911"></a>        <span class='hs-varid'>mbTvNames</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>varTToName_maybe</span> <span class='hs-varop'>$</span>
<a name="line-912"></a>                        <span class='hs-varid'>drop</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>unapResTy</span> <span class='hs-comment'>-</span> <span class='hs-num'>2</span><span class='hs-layout'>)</span> <span class='hs-varid'>unapResTy</span>
<a name="line-913"></a>        <span class='hs-comment'>-- We use Map.fromList to ensure that if there are any duplicate type</span>
<a name="line-914"></a>        <span class='hs-comment'>-- variables (as can happen in a GADT), the rightmost type variable gets</span>
<a name="line-915"></a>        <span class='hs-comment'>-- associated with the map function.</span>
<a name="line-916"></a>        <span class='hs-comment'>--</span>
<a name="line-917"></a>        <span class='hs-comment'>-- See Note [Matching functions with GADT type variables]</span>
<a name="line-918"></a>        <span class='hs-varid'>tvMap</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>fromList</span>
<a name="line-919"></a>                    <span class='hs-varop'>.</span> <span class='hs-varid'>catMaybes</span> <span class='hs-comment'>-- Drop refined types</span>
<a name="line-920"></a>                    <span class='hs-varop'>$</span> <span class='hs-varid'>zipWith</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>mbTvName</span> <span class='hs-varid'>sp</span> <span class='hs-keyglyph'>-&gt;</span>
<a name="line-921"></a>                                  <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>tvName</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-layout'>(</span><span class='hs-varid'>tvName</span><span class='hs-layout'>,</span> <span class='hs-varid'>sp</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>mbTvName</span><span class='hs-layout'>)</span>
<a name="line-922"></a>                              <span class='hs-varid'>mbTvNames</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>map1</span><span class='hs-layout'>,</span> <span class='hs-varid'>map2</span><span class='hs-keyglyph'>]</span>
<a name="line-923"></a>    <span class='hs-keyword'>if</span> <span class='hs-layout'>(</span><span class='hs-varid'>any</span> <span class='hs-layout'>(</span><span class='hs-varop'>`predMentionsName`</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>keys</span> <span class='hs-varid'>tvMap</span><span class='hs-layout'>)</span> <span class='hs-varid'>ctxt</span>
<a name="line-924"></a>         <span class='hs-varop'>||</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>size</span> <span class='hs-varid'>tvMap</span> <span class='hs-varop'>&lt;</span> <span class='hs-num'>2</span><span class='hs-layout'>)</span>
<a name="line-925"></a>         <span class='hs-varop'>&amp;&amp;</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>allowExQuant</span> <span class='hs-layout'>(</span><span class='hs-varid'>biFunToClass</span> <span class='hs-varid'>biFun</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-926"></a>       <span class='hs-keyword'>then</span> <span class='hs-varid'>existentialContextError</span> <span class='hs-varid'>conName</span>
<a name="line-927"></a>       <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>argTys</span><span class='hs-layout'>,</span> <span class='hs-varid'>tvMap</span><span class='hs-layout'>)</span>
<a name="line-928"></a>
<a name="line-929"></a><span class='hs-comment'>{-
<a name="line-930"></a>Note [Matching functions with GADT type variables]
<a name="line-931"></a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<a name="line-932"></a>
<a name="line-933"></a>When deriving Bifoldable, there is a tricky corner case to consider:
<a name="line-934"></a>
<a name="line-935"></a>  data Both a b where
<a name="line-936"></a>    BothCon :: x -&gt; x -&gt; Both x x
<a name="line-937"></a>
<a name="line-938"></a>Which fold functions should be applied to which arguments of BothCon? We have a
<a name="line-939"></a>choice, since both the function of type (a -&gt; m) and of type (b -&gt; m) can be
<a name="line-940"></a>applied to either argument. In such a scenario, the second fold function takes
<a name="line-941"></a>precedence over the first fold function, so the derived Bifoldable instance would be:
<a name="line-942"></a>
<a name="line-943"></a>  instance Bifoldable Both where
<a name="line-944"></a>    bifoldMap _ g (BothCon x1 x2) = g x1 &lt;&gt; g x2
<a name="line-945"></a>
<a name="line-946"></a>This is not an arbitrary choice, as this definition ensures that
<a name="line-947"></a>bifoldMap id = Foldable.foldMap for a derived Bifoldable instance for Both.
<a name="line-948"></a>-}</span>
<a name="line-949"></a>
<a name="line-950"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-951"></a><span class='hs-comment'>-- Error messages</span>
<a name="line-952"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-953"></a>
<a name="line-954"></a><a name="derivingKindError"></a><span class='hs-comment'>-- | Either the given data type doesn't have enough type variables, or one of</span>
<a name="line-955"></a><span class='hs-comment'>-- the type variables to be eta-reduced cannot realize kind *.</span>
<a name="line-956"></a><span class='hs-definition'>derivingKindError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-957"></a><span class='hs-definition'>derivingKindError</span> <span class='hs-varid'>biClass</span> <span class='hs-varid'>tyConName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-958"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Cannot derive well-kinded instance of form ‘"</span>
<a name="line-959"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-varid'>className</span>
<a name="line-960"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showChar</span> <span class='hs-chr'>' '</span>
<a name="line-961"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showParen</span> <span class='hs-conid'>True</span>
<a name="line-962"></a>    <span class='hs-layout'>(</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>tyConName</span><span class='hs-layout'>)</span>
<a name="line-963"></a>    <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>" ..."</span>
<a name="line-964"></a>    <span class='hs-layout'>)</span>
<a name="line-965"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘\n\tClass "</span>
<a name="line-966"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-varid'>className</span>
<a name="line-967"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>" expects an argument of kind * -&gt; * -&gt; *"</span>
<a name="line-968"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-969"></a>  <span class='hs-keyword'>where</span>
<a name="line-970"></a>    <span class='hs-varid'>className</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span>
<a name="line-971"></a>    <span class='hs-varid'>className</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nameBase</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biClassName</span> <span class='hs-varid'>biClass</span>
<a name="line-972"></a>
<a name="line-973"></a><a name="contravarianceError"></a><span class='hs-comment'>-- | One of the last two type variables appeard in a contravariant position</span>
<a name="line-974"></a><span class='hs-comment'>-- when deriving Bifoldable or Bitraversable.</span>
<a name="line-975"></a><span class='hs-definition'>contravarianceError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-976"></a><span class='hs-definition'>contravarianceError</span> <span class='hs-varid'>conName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-977"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Constructor ‘"</span>
<a name="line-978"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span>
<a name="line-979"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘ must not use the last type variable(s) in a function argument"</span>
<a name="line-980"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-981"></a>
<a name="line-982"></a><a name="noFunctionsError"></a><span class='hs-comment'>-- | A constructor has a function argument in a derived Bifoldable or Bitraversable</span>
<a name="line-983"></a><span class='hs-comment'>-- instance.</span>
<a name="line-984"></a><span class='hs-definition'>noFunctionsError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-985"></a><span class='hs-definition'>noFunctionsError</span> <span class='hs-varid'>conName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-986"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Constructor ‘"</span>
<a name="line-987"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span>
<a name="line-988"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘ must not contain function types"</span>
<a name="line-989"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-990"></a>
<a name="line-991"></a><a name="datatypeContextError"></a><span class='hs-comment'>-- | The data type has a DatatypeContext which mentions one of the eta-reduced</span>
<a name="line-992"></a><span class='hs-comment'>-- type variables.</span>
<a name="line-993"></a><span class='hs-definition'>datatypeContextError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-994"></a><span class='hs-definition'>datatypeContextError</span> <span class='hs-varid'>dataName</span> <span class='hs-varid'>instanceType</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-995"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Can't make a derived instance of ‘"</span>
<a name="line-996"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>pprint</span> <span class='hs-varid'>instanceType</span><span class='hs-layout'>)</span>
<a name="line-997"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘:\n\tData type ‘"</span>
<a name="line-998"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>dataName</span><span class='hs-layout'>)</span>
<a name="line-999"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘ must not have a class context involving the last type argument(s)"</span>
<a name="line-1000"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-1001"></a>
<a name="line-1002"></a><a name="existentialContextError"></a><span class='hs-comment'>-- | The data type has an existential constraint which mentions one of the</span>
<a name="line-1003"></a><span class='hs-comment'>-- eta-reduced type variables.</span>
<a name="line-1004"></a><span class='hs-definition'>existentialContextError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-1005"></a><span class='hs-definition'>existentialContextError</span> <span class='hs-varid'>conName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-1006"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Constructor ‘"</span>
<a name="line-1007"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span>
<a name="line-1008"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘ must be truly polymorphic in the last argument(s) of the data type"</span>
<a name="line-1009"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-1010"></a>
<a name="line-1011"></a><a name="outOfPlaceTyVarError"></a><span class='hs-comment'>-- | The data type mentions one of the n eta-reduced type variables in a place other</span>
<a name="line-1012"></a><span class='hs-comment'>-- than the last nth positions of a data type in a constructor's field.</span>
<a name="line-1013"></a><span class='hs-definition'>outOfPlaceTyVarError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-1014"></a><span class='hs-definition'>outOfPlaceTyVarError</span> <span class='hs-varid'>conName</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-1015"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Constructor ‘"</span>
<a name="line-1016"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-layout'>(</span><span class='hs-varid'>nameBase</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span>
<a name="line-1017"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"‘ must only use its last two type variable(s) within"</span>
<a name="line-1018"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>" the last two argument(s) of a data type"</span>
<a name="line-1019"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-1020"></a>
<a name="line-1021"></a><a name="etaReductionError"></a><span class='hs-comment'>-- | One of the last type variables cannot be eta-reduced (see the canEtaReduce</span>
<a name="line-1022"></a><span class='hs-comment'>-- function for the criteria it would have to meet).</span>
<a name="line-1023"></a><span class='hs-definition'>etaReductionError</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Type</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-varid'>a</span>
<a name="line-1024"></a><span class='hs-definition'>etaReductionError</span> <span class='hs-varid'>instanceType</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span>
<a name="line-1025"></a>  <span class='hs-str'>"Cannot eta-reduce to an instance of form \n\tinstance (...) =&gt; "</span>
<a name="line-1026"></a>  <span class='hs-varop'>++</span> <span class='hs-varid'>pprint</span> <span class='hs-varid'>instanceType</span>
<a name="line-1027"></a>
<a name="line-1028"></a><span class='hs-cpp'>#if !(MIN_VERSION_template_haskell(2,7,0))</span>
<a name="line-1029"></a><a name="dataConIError"></a><span class='hs-comment'>-- | Template Haskell didn't list all of a data family's instances upon reification</span>
<a name="line-1030"></a><span class='hs-comment'>-- until template-haskell-2.7.0.0, which is necessary for a derived instance to work.</span>
<a name="line-1031"></a><span class='hs-definition'>dataConIError</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span>
<a name="line-1032"></a><span class='hs-definition'>dataConIError</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span>
<a name="line-1033"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"Cannot use a data constructor."</span>
<a name="line-1034"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"\n\t(Note: if you are trying to derive for a data family instance,"</span>
<a name="line-1035"></a>  <span class='hs-varop'>.</span> <span class='hs-varid'>showString</span> <span class='hs-str'>"\n\tuse GHC &gt;= 7.4 instead.)"</span>
<a name="line-1036"></a>  <span class='hs-varop'>$</span> <span class='hs-str'>""</span>
<a name="line-1037"></a><span class='hs-cpp'>#endif</span>
<a name="line-1038"></a>
<a name="line-1039"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-1040"></a><span class='hs-comment'>-- Class-specific constants</span>
<a name="line-1041"></a><span class='hs-comment'>-------------------------------------------------------------------------------</span>
<a name="line-1042"></a>
<a name="line-1043"></a><a name="BiClass"></a><span class='hs-comment'>-- | A representation of which class is being derived.</span>
<a name="line-1044"></a><a name="BiClass"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bifunctor</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Bifoldable</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Bitraversable</span>
<a name="line-1045"></a>
<a name="line-1046"></a><a name="BiFun"></a><span class='hs-comment'>-- | A representation of which function is being generated.</span>
<a name="line-1047"></a><a name="BiFun"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bimap</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Bifoldr</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>BifoldMap</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Bitraverse</span>
<a name="line-1048"></a>  <span class='hs-keyword'>deriving</span> <span class='hs-conid'>Eq</span>
<a name="line-1049"></a>
<a name="line-1050"></a><a name="biFunConstName"></a><span class='hs-definition'>biFunConstName</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1051"></a><span class='hs-definition'>biFunConstName</span> <span class='hs-conid'>Bimap</span>      <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bimapConstValName</span>
<a name="line-1052"></a><span class='hs-definition'>biFunConstName</span> <span class='hs-conid'>Bifoldr</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldrConstValName</span>
<a name="line-1053"></a><span class='hs-definition'>biFunConstName</span> <span class='hs-conid'>BifoldMap</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldMapConstValName</span>
<a name="line-1054"></a><span class='hs-definition'>biFunConstName</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bitraverseConstValName</span>
<a name="line-1055"></a>
<a name="line-1056"></a><a name="biClassName"></a><span class='hs-definition'>biClassName</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1057"></a><span class='hs-definition'>biClassName</span> <span class='hs-conid'>Bifunctor</span>     <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifunctorTypeName</span>
<a name="line-1058"></a><span class='hs-definition'>biClassName</span> <span class='hs-conid'>Bifoldable</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldableTypeName</span>
<a name="line-1059"></a><span class='hs-definition'>biClassName</span> <span class='hs-conid'>Bitraversable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bitraversableTypeName</span>
<a name="line-1060"></a>
<a name="line-1061"></a><a name="biFunName"></a><span class='hs-definition'>biFunName</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1062"></a><span class='hs-definition'>biFunName</span> <span class='hs-conid'>Bimap</span>      <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bimapValName</span>
<a name="line-1063"></a><span class='hs-definition'>biFunName</span> <span class='hs-conid'>Bifoldr</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldrValName</span>
<a name="line-1064"></a><span class='hs-definition'>biFunName</span> <span class='hs-conid'>BifoldMap</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldMapValName</span>
<a name="line-1065"></a><span class='hs-definition'>biFunName</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bitraverseValName</span>
<a name="line-1066"></a>
<a name="line-1067"></a><a name="biClassToFuns"></a><span class='hs-definition'>biClassToFuns</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>BiFun</span><span class='hs-keyglyph'>]</span>
<a name="line-1068"></a><span class='hs-definition'>biClassToFuns</span> <span class='hs-conid'>Bifunctor</span>     <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bimap</span><span class='hs-keyglyph'>]</span>
<a name="line-1069"></a><span class='hs-definition'>biClassToFuns</span> <span class='hs-conid'>Bifoldable</span>    <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bifoldr</span><span class='hs-layout'>,</span> <span class='hs-conid'>BifoldMap</span><span class='hs-keyglyph'>]</span>
<a name="line-1070"></a><span class='hs-definition'>biClassToFuns</span> <span class='hs-conid'>Bitraversable</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bitraverse</span><span class='hs-keyglyph'>]</span>
<a name="line-1071"></a>
<a name="line-1072"></a><a name="biFunToClass"></a><span class='hs-definition'>biFunToClass</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>BiClass</span>
<a name="line-1073"></a><span class='hs-definition'>biFunToClass</span> <span class='hs-conid'>Bimap</span>      <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bifunctor</span>
<a name="line-1074"></a><span class='hs-definition'>biFunToClass</span> <span class='hs-conid'>Bifoldr</span>    <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bifoldable</span>
<a name="line-1075"></a><span class='hs-definition'>biFunToClass</span> <span class='hs-conid'>BifoldMap</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bifoldable</span>
<a name="line-1076"></a><span class='hs-definition'>biFunToClass</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Bitraversable</span>
<a name="line-1077"></a>
<a name="line-1078"></a><a name="biClassConstraint"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Name</span>
<a name="line-1079"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-conid'>Bifunctor</span>     <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>functorTypeName</span>
<a name="line-1080"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-conid'>Bifoldable</span>    <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>foldableTypeName</span>
<a name="line-1081"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-conid'>Bitraversable</span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>traversableTypeName</span>
<a name="line-1082"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-varid'>biClass</span>       <span class='hs-num'>2</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biClassName</span> <span class='hs-varid'>biClass</span>
<a name="line-1083"></a><span class='hs-definition'>biClassConstraint</span> <span class='hs-keyword'>_</span>             <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-1084"></a>
<a name="line-1085"></a><a name="biFunArity"></a><span class='hs-definition'>biFunArity</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Name</span>
<a name="line-1086"></a><span class='hs-definition'>biFunArity</span> <span class='hs-conid'>Bimap</span>      <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>fmapValName</span>
<a name="line-1087"></a><span class='hs-definition'>biFunArity</span> <span class='hs-conid'>Bifoldr</span>    <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>foldrValName</span>
<a name="line-1088"></a><span class='hs-definition'>biFunArity</span> <span class='hs-conid'>BifoldMap</span>  <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>foldMapValName</span>
<a name="line-1089"></a><span class='hs-definition'>biFunArity</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>traverseValName</span>
<a name="line-1090"></a><span class='hs-definition'>biFunArity</span> <span class='hs-varid'>biFun</span>      <span class='hs-num'>2</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varop'>$</span> <span class='hs-varid'>biFunName</span> <span class='hs-varid'>biFun</span>
<a name="line-1091"></a><span class='hs-definition'>biFunArity</span> <span class='hs-keyword'>_</span>          <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-1092"></a>
<a name="line-1093"></a><a name="allowFunTys"></a><span class='hs-definition'>allowFunTys</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Bool</span>
<a name="line-1094"></a><span class='hs-definition'>allowFunTys</span> <span class='hs-conid'>Bifunctor</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-1095"></a><span class='hs-definition'>allowFunTys</span> <span class='hs-keyword'>_</span>         <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-1096"></a>
<a name="line-1097"></a><a name="allowExQuant"></a><span class='hs-definition'>allowExQuant</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiClass</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Bool</span>
<a name="line-1098"></a><span class='hs-definition'>allowExQuant</span> <span class='hs-conid'>Bifoldable</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-1099"></a><span class='hs-definition'>allowExQuant</span> <span class='hs-keyword'>_</span>          <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-1100"></a>
<a name="line-1101"></a><a name="biFunTriv"></a><span class='hs-comment'>-- See Trac #7436 for why explicit lambdas are used</span>
<a name="line-1102"></a><span class='hs-definition'>biFunTriv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1103"></a><span class='hs-definition'>biFunTriv</span> <span class='hs-conid'>Bimap</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-1104"></a>  <span class='hs-varid'>x</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"x"</span>
<a name="line-1105"></a>  <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>varP</span> <span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>x</span>
<a name="line-1106"></a><span class='hs-comment'>-- The biFunTriv definitions for bifoldr, bifoldMap, and bitraverse might seem</span>
<a name="line-1107"></a><span class='hs-comment'>-- useless, but they do serve a purpose.</span>
<a name="line-1108"></a><span class='hs-comment'>-- See Note [biFunTriv for Bifoldable and Bitraversable]</span>
<a name="line-1109"></a><span class='hs-definition'>biFunTriv</span> <span class='hs-conid'>Bifoldr</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-1110"></a>  <span class='hs-varid'>z</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"z"</span>
<a name="line-1111"></a>  <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>wildP</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>z</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>z</span>
<a name="line-1112"></a><span class='hs-definition'>biFunTriv</span> <span class='hs-conid'>BifoldMap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>wildP</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>memptyValName</span>
<a name="line-1113"></a><span class='hs-definition'>biFunTriv</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>pureValName</span>
<a name="line-1114"></a>
<a name="line-1115"></a><a name="biFunApp"></a><span class='hs-definition'>biFunApp</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1116"></a><span class='hs-definition'>biFunApp</span> <span class='hs-conid'>Bifoldr</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-1117"></a>  <span class='hs-varid'>x</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"x"</span>
<a name="line-1118"></a>  <span class='hs-varid'>z</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newName</span> <span class='hs-str'>"z"</span>
<a name="line-1119"></a>  <span class='hs-varid'>lamE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>varP</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>z</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>$</span> <span class='hs-varid'>appsE</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>e</span><span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>z</span><span class='hs-layout'>,</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
<a name="line-1120"></a><span class='hs-definition'>biFunApp</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>e</span>
<a name="line-1121"></a>
<a name="line-1122"></a><a name="biFunCombine"></a><span class='hs-definition'>biFunCombine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BiFun</span>
<a name="line-1123"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1124"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1125"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1126"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-1127"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1128"></a><span class='hs-definition'>biFunCombine</span> <span class='hs-conid'>Bimap</span>      <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bimapCombine</span>
<a name="line-1129"></a><span class='hs-definition'>biFunCombine</span> <span class='hs-conid'>Bifoldr</span>    <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldrCombine</span>
<a name="line-1130"></a><span class='hs-definition'>biFunCombine</span> <span class='hs-conid'>BifoldMap</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bifoldMapCombine</span>
<a name="line-1131"></a><span class='hs-definition'>biFunCombine</span> <span class='hs-conid'>Bitraverse</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bitraverseCombine</span>
<a name="line-1132"></a>
<a name="line-1133"></a><a name="bimapCombine"></a><span class='hs-definition'>bimapCombine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-1134"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1135"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1136"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-1137"></a>             <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1138"></a><span class='hs-definition'>bimapCombine</span> <span class='hs-varid'>conName</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-varid'>foldl'</span> <span class='hs-conid'>AppE</span> <span class='hs-layout'>(</span><span class='hs-conid'>ConE</span> <span class='hs-varid'>conName</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>fromEither</span><span class='hs-layout'>)</span>
<a name="line-1139"></a>
<a name="line-1140"></a><span class='hs-comment'>-- bifoldr, bifoldMap, and bitraverse are handled differently from bimap, since</span>
<a name="line-1141"></a><span class='hs-comment'>-- they filter out subexpressions whose types do not mention one of the last two</span>
<a name="line-1142"></a><span class='hs-comment'>-- type parameters. See</span>
<a name="line-1143"></a><span class='hs-comment'>-- https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/DeriveFunctor#AlternativestrategyforderivingFoldableandTraversable</span>
<a name="line-1144"></a><span class='hs-comment'>-- for further discussion.</span>
<a name="line-1145"></a>
<a name="line-1146"></a><a name="bifoldrCombine"></a><span class='hs-definition'>bifoldrCombine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-1147"></a>               <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1148"></a>               <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1149"></a>               <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-1150"></a>               <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1151"></a><span class='hs-definition'>bifoldrCombine</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>zName</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-varid'>foldr</span> <span class='hs-conid'>AppE</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarE</span> <span class='hs-varid'>zName</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>rights</span><span class='hs-layout'>)</span>
<a name="line-1152"></a>
<a name="line-1153"></a><a name="bifoldMapCombine"></a><span class='hs-definition'>bifoldMapCombine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-1154"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1155"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1156"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-1157"></a>                 <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1158"></a><span class='hs-definition'>bifoldMapCombine</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varop'>.</span> <span class='hs-varid'>rights</span><span class='hs-layout'>)</span>
<a name="line-1159"></a>  <span class='hs-keyword'>where</span>
<a name="line-1160"></a>    <span class='hs-varid'>go</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Exp</span>
<a name="line-1161"></a>    <span class='hs-varid'>go</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>VarE</span> <span class='hs-varid'>memptyValName</span>
<a name="line-1162"></a>    <span class='hs-varid'>go</span> <span class='hs-varid'>es</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr1</span> <span class='hs-layout'>(</span><span class='hs-conid'>AppE</span> <span class='hs-varop'>.</span> <span class='hs-conid'>AppE</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarE</span> <span class='hs-varid'>mappendValName</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>es</span>
<a name="line-1163"></a>
<a name="line-1164"></a><a name="bitraverseCombine"></a><span class='hs-definition'>bitraverseCombine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Name</span>
<a name="line-1165"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Name</span>
<a name="line-1166"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1167"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Either</span> <span class='hs-conid'>Exp</span> <span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span>
<a name="line-1168"></a>                  <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1169"></a><span class='hs-definition'>bitraverseCombine</span> <span class='hs-varid'>conName</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>args</span> <span class='hs-varid'>essQ</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-1170"></a>    <span class='hs-varid'>ess</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>essQ</span>
<a name="line-1171"></a>
<a name="line-1172"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>argTysTyVarInfo</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Bool</span><span class='hs-keyglyph'>]</span>
<a name="line-1173"></a>        <span class='hs-varid'>argTysTyVarInfo</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>isRight</span> <span class='hs-varid'>ess</span>
<a name="line-1174"></a>
<a name="line-1175"></a>        <span class='hs-varid'>argsWithTyVar</span><span class='hs-layout'>,</span> <span class='hs-varid'>argsWithoutTyVar</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Name</span><span class='hs-keyglyph'>]</span>
<a name="line-1176"></a>        <span class='hs-layout'>(</span><span class='hs-varid'>argsWithTyVar</span><span class='hs-layout'>,</span> <span class='hs-varid'>argsWithoutTyVar</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>partitionByList</span> <span class='hs-varid'>argTysTyVarInfo</span> <span class='hs-varid'>args</span>
<a name="line-1177"></a>
<a name="line-1178"></a>        <span class='hs-varid'>conExpQ</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Q</span> <span class='hs-conid'>Exp</span>
<a name="line-1179"></a>        <span class='hs-varid'>conExpQ</span>
<a name="line-1180"></a>          <span class='hs-keyglyph'>|</span> <span class='hs-varid'>null</span> <span class='hs-varid'>argsWithTyVar</span>
<a name="line-1181"></a>          <span class='hs-keyglyph'>=</span> <span class='hs-varid'>appsE</span> <span class='hs-layout'>(</span><span class='hs-varid'>conE</span> <span class='hs-varid'>conName</span><span class='hs-conop'>:</span><span class='hs-varid'>map</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>argsWithoutTyVar</span><span class='hs-layout'>)</span>
<a name="line-1182"></a>          <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-1183"></a>              <span class='hs-varid'>bs</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>newNameList</span> <span class='hs-str'>"b"</span> <span class='hs-varop'>$</span> <span class='hs-varid'>length</span> <span class='hs-varid'>args</span>
<a name="line-1184"></a>              <span class='hs-keyword'>let</span> <span class='hs-varid'>bs'</span>  <span class='hs-keyglyph'>=</span> <span class='hs-varid'>filterByList</span>  <span class='hs-varid'>argTysTyVarInfo</span> <span class='hs-varid'>bs</span>
<a name="line-1185"></a>                  <span class='hs-varid'>vars</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>filterByLists</span> <span class='hs-varid'>argTysTyVarInfo</span>
<a name="line-1186"></a>                                       <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>bs</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varE</span> <span class='hs-varid'>args</span><span class='hs-layout'>)</span>
<a name="line-1187"></a>              <span class='hs-varid'>lamE</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>varP</span> <span class='hs-varid'>bs'</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>appsE</span> <span class='hs-layout'>(</span><span class='hs-varid'>conE</span> <span class='hs-varid'>conName</span><span class='hs-conop'>:</span><span class='hs-varid'>vars</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-1188"></a>
<a name="line-1189"></a>    <span class='hs-varid'>conExp</span> <span class='hs-keyglyph'>&lt;-</span> <span class='hs-varid'>conExpQ</span>
<a name="line-1190"></a>
<a name="line-1191"></a>    <span class='hs-keyword'>let</span> <span class='hs-varid'>go</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Exp</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>Exp</span>
<a name="line-1192"></a>        <span class='hs-varid'>go</span> <span class='hs-conid'>[]</span>  <span class='hs-keyglyph'>=</span> <span class='hs-conid'>VarE</span> <span class='hs-varid'>pureValName</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>conExp</span>
<a name="line-1193"></a>        <span class='hs-varid'>go</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>e</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>VarE</span> <span class='hs-varid'>fmapValName</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>conExp</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>e</span>
<a name="line-1194"></a>        <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-varid'>e1</span><span class='hs-conop'>:</span><span class='hs-varid'>e2</span><span class='hs-conop'>:</span><span class='hs-varid'>es</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldl'</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>se1</span> <span class='hs-varid'>se2</span> <span class='hs-keyglyph'>-&gt;</span> <span class='hs-conid'>InfixE</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>se1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>VarE</span> <span class='hs-varid'>apValName</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>se2</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-1195"></a>          <span class='hs-layout'>(</span><span class='hs-conid'>VarE</span> <span class='hs-varid'>liftA2ValName</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>conExp</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>e1</span> <span class='hs-varop'>`AppE`</span> <span class='hs-varid'>e2</span><span class='hs-layout'>)</span> <span class='hs-varid'>es</span>
<a name="line-1196"></a>
<a name="line-1197"></a>    <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>go</span> <span class='hs-varop'>.</span> <span class='hs-varid'>rights</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ess</span>
<a name="line-1198"></a>
<a name="line-1199"></a><span class='hs-comment'>{-
<a name="line-1200"></a>Note [biFunTriv for Bifoldable and Bitraversable]
<a name="line-1201"></a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<a name="line-1202"></a>When deriving Bifoldable and Bitraversable, we filter out any subexpressions whose
<a name="line-1203"></a>type does not mention one of the last two type parameters. From this, you might
<a name="line-1204"></a>think that we don't need to implement biFunTriv for bifoldr, bifoldMap, or
<a name="line-1205"></a>bitraverse at all, but in fact we do need to. Imagine the following data type:
<a name="line-1206"></a>
<a name="line-1207"></a>    data T a b = MkT a (T Int b)
<a name="line-1208"></a>
<a name="line-1209"></a>In a derived Bifoldable T instance, you would generate the following bifoldMap
<a name="line-1210"></a>definition:
<a name="line-1211"></a>
<a name="line-1212"></a>    bifoldMap f g (MkT a1 a2) = f a1 &lt;&gt; bifoldMap (\_ -&gt; mempty) g arg2
<a name="line-1213"></a>
<a name="line-1214"></a>You need to fill in biFunTriv (\_ -&gt; mempty) as the first argument to the recursive
<a name="line-1215"></a>call to bifoldMap, since that is how the algorithm handles polymorphic recursion.
<a name="line-1216"></a>-}</span>
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