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authorRyan Scott <ryan.gl.scott@gmail.com>2021-04-27 19:02:03 -0400
committerBen Gamari <ben@smart-cactus.org>2021-05-12 20:27:10 -0400
commit4a24635522790b0713de0f2eef4d1333fc8a4761 (patch)
treee462b32a0e460c0685be36d99e375f56712fb054
parenta7c9f8a79b2da9cb02e5b15147e33cebbb8b69c6 (diff)
downloadhaskell-4a24635522790b0713de0f2eef4d1333fc8a4761.tar.gz
Propagate free variables in extract_lctxt correctly
This fixes an oversight in the implementation of `extract_lctxt` which was introduced in commit ce85cffc. Fixes #19759. (cherry picked from commit c2541c49f162f1d03b0ae55f47b9c76cc96df76f)
-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 a7f28b69cc..3a570e2e14 100644
--- a/compiler/GHC/Rename/HsType.hs
+++ b/compiler/GHC/Rename/HsType.hs
@@ -1911,7 +1911,7 @@ 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 36567db6e7..70342cc45a 100644
--- a/testsuite/tests/th/all.T
+++ b/testsuite/tests/th/all.T
@@ -522,3 +522,4 @@ test('T18740d', normal, compile_fail, [''])
test('T19363', normal, compile_and_run, [''])
test('T19377', normal, compile, [''])
test('T17804', normal, compile, [''])
+test('T19759', normal, compile, [''])