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Diffstat (limited to 'testsuite/tests/indexed-types/should_compile/T18875.hs')
| -rw-r--r-- | testsuite/tests/indexed-types/should_compile/T18875.hs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/testsuite/tests/indexed-types/should_compile/T18875.hs b/testsuite/tests/indexed-types/should_compile/T18875.hs new file mode 100644 index 0000000000..60fd1cb86a --- /dev/null +++ b/testsuite/tests/indexed-types/should_compile/T18875.hs @@ -0,0 +1,11 @@ +{-# LANGUAGE TypeFamilies #-} + +module T18875 where + +-- This exercises Note [Type variable cycles in Givens] in GHC.Tc.Solver.Canonical + +type family G a b where + G (Maybe c) d = d + +h :: (e ~ Maybe (G e f)) => e -> f +h (Just x) = x |