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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-12-13 10:46:26 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2017-12-13 10:52:10 +0000 |
| commit | e40db7b1676627f5291b463405338e7b69fa3f69 (patch) | |
| tree | 8426bae8d6097dcd89fc55282c0167bae33b12b9 /testsuite/tests/polykinds/T14561.hs | |
| parent | a106a200892e2ac7953f0929c303d392c8808f89 (diff) | |
| download | haskell-e40db7b1676627f5291b463405338e7b69fa3f69.tar.gz | |
Detect levity-polymorphic uses of unsafeCoerce#
This bug was shown up by Trac #14561. The deguarer carefully
detects unsaturated and levity-polymorphic uses of primops,
but not of things like unsafeCoerce#.
The fix is simple: see Note [Levity-polymorphic Ids] in Id.
Diffstat (limited to 'testsuite/tests/polykinds/T14561.hs')
| -rw-r--r-- | testsuite/tests/polykinds/T14561.hs | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/testsuite/tests/polykinds/T14561.hs b/testsuite/tests/polykinds/T14561.hs new file mode 100644 index 0000000000..f528e7c813 --- /dev/null +++ b/testsuite/tests/polykinds/T14561.hs @@ -0,0 +1,18 @@ +{-# LANGUAGE TypeInType #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE MagicHash #-} + +module T14561 where + +import GHC.Types +import GHC.Prim + +badId :: forall (a :: TYPE r). a -> a +badId = unsafeCoerce# +-- Un-saturated application of a levity-polymorphic +-- function that must be eta-expanded + +goodId :: forall (a :: Type). a -> a +goodId = unsafeCoerce# +-- But this one is OK |