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-rw-r--r--haddock-api/src/Haddock/Interface/Specialize.hs20
-rw-r--r--html-test/ref/Bug679.html196
-rw-r--r--html-test/src/Bug679.hs24
3 files changed, 230 insertions, 10 deletions
diff --git a/haddock-api/src/Haddock/Interface/Specialize.hs b/haddock-api/src/Haddock/Interface/Specialize.hs
index 6d2888d3..bb27f10c 100644
--- a/haddock-api/src/Haddock/Interface/Specialize.hs
+++ b/haddock-api/src/Haddock/Interface/Specialize.hs
@@ -31,23 +31,23 @@ import qualified Data.Set as Set
specialize :: forall name a. (Ord (IdP name), DataId name, NamedThing (IdP name))
=> Data a
=> [(IdP name, HsType name)] -> a -> a
-specialize specs = go
+specialize specs = go spec_map0
where
- go :: forall x. Data x => x -> x
- go = everywhereButType @name $ mkT $ sugar . strip_kind_sig . specialize_ty_var
+ go :: forall x. Data x => Map name (HsType name) -> x -> x
+ go spec_map = everywhereButType @name $ mkT $ sugar . strip_kind_sig . specialize_ty_var spec_map
strip_kind_sig :: HsType name -> HsType name
strip_kind_sig (HsKindSig (L _ t) _) = t
strip_kind_sig typ = typ
- specialize_ty_var :: HsType name -> HsType name
- specialize_ty_var (HsTyVar _ (L _ name'))
+ specialize_ty_var :: Map name (HsType name) -> HsType name -> HsType name
+ specialize_ty_var spec_map (HsTyVar _ (L _ name'))
| Just t <- Map.lookup name' spec_map = t
- specialize_ty_var typ = typ
- -- This is a tricky recursive definition that is guaranteed to terminate
- -- because a type binder cannot be instantiated with a type that depends
- -- on that binder. i.e. @a -> Maybe a@ is invalid
- spec_map = Map.fromList [ (n, go t) | (n, t) <- specs]
+ specialize_ty_var _ typ = typ
+
+ -- This is a tricky recursive definition. By adding in the specializations
+ -- one by one, we should avoid infinite loops.
+ spec_map0 = foldr (\(n,t) acc -> Map.insert n (go acc t) acc) mempty specs
-- | Instantiate given binders with corresponding types.
diff --git a/html-test/ref/Bug679.html b/html-test/ref/Bug679.html
new file mode 100644
index 00000000..ddec7a12
--- /dev/null
+++ b/html-test/ref/Bug679.html
@@ -0,0 +1,196 @@
+<html xmlns="http://www.w3.org/1999/xhtml"
+><head
+ ><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"
+ /><title
+ >Bug679</title
+ ><link href="#" rel="stylesheet" type="text/css" title="Ocean"
+ /><link rel="stylesheet" type="text/css" href="#"
+ /><script src="haddock-bundle.min.js" async="async" type="text/javascript"
+ ></script
+ ><script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"
+ ></script
+ ></head
+ ><body
+ ><div id="package-header"
+ ><ul class="links" id="page-menu"
+ ><li
+ ><a href="#"
+ >Contents</a
+ ></li
+ ><li
+ ><a href="#"
+ >Index</a
+ ></li
+ ></ul
+ ><p class="caption empty"
+ ></p
+ ></div
+ ><div id="content"
+ ><div id="module-header"
+ ><table class="info"
+ ><tr
+ ><th
+ >Safe Haskell</th
+ ><td
+ >None</td
+ ></tr
+ ></table
+ ><p class="caption"
+ >Bug679</p
+ ></div
+ ><div id="interface"
+ ><h1
+ >Documentation</h1
+ ><div class="top"
+ ><p class="src"
+ ><span class="keyword"
+ >data</span
+ > <a id="t:Bar" class="def"
+ >Bar</a
+ > a <a href="#" class="selflink"
+ >#</a
+ ></p
+ ><div class="subs constructors"
+ ><p class="caption"
+ >Constructors</p
+ ><table
+ ><tr
+ ><td class="src"
+ ><a id="v:Bar" class="def"
+ >Bar</a
+ ></td
+ ><td class="doc empty"
+ ></td
+ ></tr
+ ></table
+ ></div
+ ><div class="subs instances"
+ ><details id="i:Bar" open="open"
+ ><summary
+ >Instances</summary
+ ><table
+ ><tr
+ ><td class="src clearfix"
+ ><span class="inst-left"
+ ><span class="instance details-toggle-control details-toggle" data-details-id="i:id:Bar:Foo:1"
+ ></span
+ > <a href="#"
+ >Foo</a
+ > (<a href="#"
+ >Bar</a
+ > a)</span
+ > <a href="#" class="selflink"
+ >#</a
+ ></td
+ ><td class="doc empty"
+ ></td
+ ></tr
+ ><tr
+ ><td colspan="2"
+ ><details id="i:id:Bar:Foo:1"
+ ><summary class="hide-when-js-enabled"
+ >Instance details</summary
+ ><div class="subs methods"
+ ><p class="caption"
+ >Methods</p
+ ><p class="src"
+ ><a href="#"
+ >foo</a
+ > :: <a href="#"
+ >Bar</a
+ > a -&gt; <a href="#"
+ >Bar</a
+ > a <a href="#" class="selflink"
+ >#</a
+ ></p
+ ></div
+ ></details
+ ></td
+ ></tr
+ ></table
+ ></details
+ ></div
+ ></div
+ ><div class="top"
+ ><p class="src"
+ ><span class="keyword"
+ >class</span
+ > <a id="t:Foo" class="def"
+ >Foo</a
+ > a <span class="keyword"
+ >where</span
+ > <a href="#" class="selflink"
+ >#</a
+ ></p
+ ><div class="subs minimal"
+ ><p class="caption"
+ >Minimal complete definition</p
+ ><p class="src"
+ ><a href="#"
+ >foo</a
+ ></p
+ ></div
+ ><div class="subs methods"
+ ><p class="caption"
+ >Methods</p
+ ><p class="src"
+ ><a id="v:foo" class="def"
+ >foo</a
+ > :: a -&gt; a <a href="#" class="selflink"
+ >#</a
+ ></p
+ ></div
+ ><div class="subs instances"
+ ><details id="i:Foo" open="open"
+ ><summary
+ >Instances</summary
+ ><table
+ ><tr
+ ><td class="src clearfix"
+ ><span class="inst-left"
+ ><span class="instance details-toggle-control details-toggle" data-details-id="i:ic:Foo:Foo:1"
+ ></span
+ > <a href="#"
+ >Foo</a
+ > (<a href="#"
+ >Bar</a
+ > a)</span
+ > <a href="#" class="selflink"
+ >#</a
+ ></td
+ ><td class="doc empty"
+ ></td
+ ></tr
+ ><tr
+ ><td colspan="2"
+ ><details id="i:ic:Foo:Foo:1"
+ ><summary class="hide-when-js-enabled"
+ >Instance details</summary
+ ><div class="subs methods"
+ ><p class="caption"
+ >Methods</p
+ ><p class="src"
+ ><a href="#"
+ >foo</a
+ > :: <a href="#"
+ >Bar</a
+ > a -&gt; <a href="#"
+ >Bar</a
+ > a <a href="#" class="selflink"
+ >#</a
+ ></p
+ ></div
+ ></details
+ ></td
+ ></tr
+ ></table
+ ></details
+ ></div
+ ></div
+ ></div
+ ></div
+ ><div id="footer"
+ ></div
+ ></body
+ ></html
+> \ No newline at end of file
diff --git a/html-test/src/Bug679.hs b/html-test/src/Bug679.hs
new file mode 100644
index 00000000..dba194c4
--- /dev/null
+++ b/html-test/src/Bug679.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+module Bug679 where
+
+import Language.Haskell.TH
+
+data Bar a = Bar
+
+$(do
+ a <- newName "a"
+
+ let classN = mkName "Foo"
+ let methodN = mkName "foo"
+
+ methodTy <- [t| $(varT a) -> $(varT a) |]
+ let cla = ClassD [] classN [PlainTV a] [] [SigD methodN methodTy]
+
+ -- Note that we are /reusing/ the same type variable 'a' as in the class
+ instanceHead <- [t| $(conT classN) (Bar $(varT a)) |]
+ idCall <- [e| id |]
+ let ins = InstanceD Nothing [] instanceHead [FunD methodN [Clause [] (NormalB idCall) []]]
+
+ pure [cla,ins])
+
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