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authorRyan Scott <ryan.gl.scott@gmail.com>2021-04-27 19:02:03 -0400
committerRyan Scott <ryan.gl.scott@gmail.com>2021-04-27 19:02:04 -0400
commitd03ae1c938d35eaaf43fc070b14522ff277f8bef (patch)
tree73b75b17126543bf48bc93cbf17c94ce73664c22
parentdd121fa178c29a154233e95a15c755d0ca7cbdcc (diff)
downloadhaskell-wip/T19759.tar.gz
Propagate free variables in extract_lctxt correctlywip/T19759
This fixes an oversight in the implementation of `extract_lctxt` which was introduced in commit ce85cffc. Fixes #19759.
-rw-r--r--compiler/GHC/Rename/HsType.hs2
-rw-r--r--testsuite/tests/th/T19759.hs25
-rw-r--r--testsuite/tests/th/all.T1
3 files changed, 27 insertions, 1 deletions
diff --git a/compiler/GHC/Rename/HsType.hs b/compiler/GHC/Rename/HsType.hs
index d11c4c9634..f92100ffe2 100644
--- a/compiler/GHC/Rename/HsType.hs
+++ b/compiler/GHC/Rename/HsType.hs
@@ -1910,7 +1910,7 @@ extractDataDefnKindVars (HsDataDefn { dd_kindSig = ksig })
= maybe [] extractHsTyRdrTyVars ksig
extract_lctxt :: Maybe (LHsContext GhcPs) -> FreeKiTyVars -> FreeKiTyVars
-extract_lctxt Nothing = const []
+extract_lctxt Nothing = id
extract_lctxt (Just ctxt) = extract_ltys (unLoc ctxt)
extract_scaled_ltys :: [HsScaled GhcPs (LHsType GhcPs)]
diff --git a/testsuite/tests/th/T19759.hs b/testsuite/tests/th/T19759.hs
new file mode 100644
index 0000000000..96c1684a0b
--- /dev/null
+++ b/testsuite/tests/th/T19759.hs
@@ -0,0 +1,25 @@
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE TemplateHaskell #-}
+module T19759 where
+
+import Language.Haskell.TH
+
+data T a where
+ MkT :: a -> b -> T a
+
+{-
+pattern MkT' :: () => forall b. a -> b -> T a
+pattern MkT' x y = MkT x y
+-}
+
+$(do let mkT' = mkName "MkT'"
+ a <- newName "a"
+ b <- newName "b"
+ x <- newName "x"
+ y <- newName "y"
+ pure [ PatSynSigD mkT' $ ForallT [] [] $ ForallT [PlainTV b SpecifiedSpec] []
+ $ ArrowT `AppT` VarT a `AppT` (ArrowT `AppT` VarT b `AppT` (ConT ''T `AppT` VarT a))
+ , PatSynD mkT' (PrefixPatSyn [x, y]) ImplBidir $
+ ConP 'MkT [] [VarP x, VarP y]
+ ])
+
diff --git a/testsuite/tests/th/all.T b/testsuite/tests/th/all.T
index fb3bc7fb49..0d0e997440 100644
--- a/testsuite/tests/th/all.T
+++ b/testsuite/tests/th/all.T
@@ -524,3 +524,4 @@ test('T19377', normal, compile, [''])
test('T17804', normal, compile, [''])
test('T19470', only_ways(['ghci']), ghci_script, ['T19470.script'])
test('T19737', normal, compile, [''])
+test('T19759', normal, compile, [''])