1 files changed, 17 insertions, 0 deletions
diff --git a/testsuite/tests/typecheck/should_compile/T18406b.hs b/testsuite/tests/typecheck/should_compile/T18406b.hs
new file mode 100644
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+++ b/testsuite/tests/typecheck/should_compile/T18406b.hs
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+{-# LANGUAGE Haskell2010 #-}
+
+{-# LANGUAGE ScopedTypeVariables, MultiParamTypeClasses, FunctionalDependencies, FlexibleContexts #-}
+
+module Bug where
+
+class C a b | a -> b where
+  op :: a -> a
+
+foo :: forall a b. C a b => a -> b -> a
+foo x y = blah x
+  where
+    -- GHC should infer
+    -- blah :: a -> a
+    -- and not
+    -- blah :: forall b0. C a b0 => a -> a
+    blah z = [x,z] `seq` op z