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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2020-09-08 19:25:11 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-09-15 15:19:44 -0400 |
| commit | c7182a5c67fe8b5bd256cb8eb805562636853ea2 (patch) | |
| tree | 6e9f04053559df514b8deab624bb9491fae27f27 /compiler/GHC/Tc/Module.hs | |
| parent | 8610bcbeb11b898f85f228b755fa8421b5ae3e34 (diff) | |
| download | haskell-c7182a5c67fe8b5bd256cb8eb805562636853ea2.tar.gz | |
Care with implicit-parameter superclasses
Two bugs, #18627 and #18649, had the same cause: we were not
account for the fact that a constaint tuple might hide an implicit
parameter.
The solution is not hard: look for implicit parameters in
superclasses. See Note [Local implicit parameters] in
GHC.Core.Predicate.
Then we use this new function in two places
* The "short-cut solver" in GHC.Tc.Solver.Interact.shortCutSolver
which simply didn't handle implicit parameters properly at all.
This fixes #18627
* The specialiser, which should not specialise on implicit parameters
This fixes #18649
There are some lingering worries (see Note [Local implicit
parameters]) but things are much better.
Diffstat (limited to 'compiler/GHC/Tc/Module.hs')
| -rw-r--r-- | compiler/GHC/Tc/Module.hs | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/compiler/GHC/Tc/Module.hs b/compiler/GHC/Tc/Module.hs index 311f87458f..20538dd230 100644 --- a/compiler/GHC/Tc/Module.hs +++ b/compiler/GHC/Tc/Module.hs @@ -65,9 +65,10 @@ import GHC.Builtin.Types ( unitTy, mkListTy ) import GHC.Driver.Plugins import GHC.Driver.Session import GHC.Hs -import GHC.Iface.Syntax ( ShowSub(..), showToHeader ) -import GHC.Iface.Type ( ShowForAllFlag(..) ) -import GHC.Core.PatSyn( pprPatSynType ) +import GHC.Iface.Syntax ( ShowSub(..), showToHeader ) +import GHC.Iface.Type ( ShowForAllFlag(..) ) +import GHC.Core.PatSyn ( pprPatSynType ) +import GHC.Core.Predicate ( classMethodTy ) import GHC.Builtin.Names import GHC.Builtin.Utils import GHC.Types.Name.Reader @@ -1014,10 +1015,8 @@ checkBootTyCon is_boot tc1 tc2 name2 = idName id2 pname1 = quotes (ppr name1) pname2 = quotes (ppr name2) - (_, rho_ty1) = splitForAllTys (idType id1) - op_ty1 = funResultTy rho_ty1 - (_, rho_ty2) = splitForAllTys (idType id2) - op_ty2 = funResultTy rho_ty2 + op_ty1 = classMethodTy id1 + op_ty2 = classMethodTy id2 eqAT (ATI tc1 def_ats1) (ATI tc2 def_ats2) = checkBootTyCon is_boot tc1 tc2 `andThenCheck` |