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| author | Richard Eisenberg <rae@cs.brynmawr.edu> | 2018-11-01 15:07:36 -0400 |
|---|---|---|
| committer | Richard Eisenberg <rae@cs.brynmawr.edu> | 2018-11-01 17:34:47 -0400 |
| commit | 255d2e323a8879a7296a5ab94e6cc49023e2c86e (patch) | |
| tree | ed7de96fa0c938998128d560799ddb9497ef269f | |
| parent | 82a716431cc680392e332bc2b1a1fd0d7faa4cd8 (diff) | |
| download | haskell-255d2e323a8879a7296a5ab94e6cc49023e2c86e.tar.gz | |
Fix embarrassing, egregious bug in roles of (->)
Previously, I had inexplicably decided that (->)'s roles
were all Representational. But, of course, its first two
parameters are *dependent* RuntimeReps. All dependent parameters
have a Nominal role, because all roles in kinds are Nominal.
Fix is easy, but I have no idea how the world hasn't come
crashing down before now.
This was found while investigating #15801, which requires
visible type application in types to observe. Hence, the test
case will come with the main patch for #12045.
| -rw-r--r-- | compiler/iface/IfaceSyn.hs | 2 | ||||
| -rw-r--r-- | compiler/types/TyCon.hs | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/compiler/iface/IfaceSyn.hs b/compiler/iface/IfaceSyn.hs index 3266c5aec1..7d1e697cdf 100644 --- a/compiler/iface/IfaceSyn.hs +++ b/compiler/iface/IfaceSyn.hs @@ -903,7 +903,7 @@ pprRoles :: (Role -> Bool) -> SDoc -> [IfaceTyConBinder] pprRoles suppress_if tyCon bndrs roles = sdocWithDynFlags $ \dflags -> let froles = suppressIfaceInvisibles dflags bndrs roles - in ppUnless (all suppress_if roles || null froles) $ + in ppUnless (all suppress_if froles || null froles) $ text "type role" <+> tyCon <+> hsep (map ppr froles) pprInfixIfDeclBndr :: ShowHowMuch -> OccName -> SDoc diff --git a/compiler/types/TyCon.hs b/compiler/types/TyCon.hs index c96cb6beb8..eeebf8b9cf 100644 --- a/compiler/types/TyCon.hs +++ b/compiler/types/TyCon.hs @@ -2259,7 +2259,7 @@ tyConRoles :: TyCon -> [Role] -- See also Note [TyCon Role signatures] tyConRoles tc = case tc of - { FunTyCon {} -> const_role Representational + { FunTyCon {} -> [Nominal, Nominal, Representational, Representational] ; AlgTyCon { tcRoles = roles } -> roles ; SynonymTyCon { tcRoles = roles } -> roles ; FamilyTyCon {} -> const_role Nominal |