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| author | Richard Eisenberg <rae@richarde.dev> | 2021-01-05 22:40:53 -0500 |
|---|---|---|
| committer | Richard Eisenberg <rae@richarde.dev> | 2021-01-15 23:14:13 -0500 |
| commit | 7d550ff71ee06c681756f60fbd3731559484afa3 (patch) | |
| tree | eab8a083e327c06272f1c95833174ecf347bea45 /compiler/GHC/Core/Coercion | |
| parent | 0dba78410887ffc3d219639081e284ef7b67560a (diff) | |
| download | haskell-wip/T19106.tar.gz | |
Make matchableGivens more reliably correct.wip/T19106
This has two fixes:
1. Take TyVarTvs into account in matchableGivens. This
fixes #19106.
2. Don't allow unifying alpha ~ Maybe alpha. This fixes
#19107.
This patch also removes a redundant Note and redirects
references to a better replacement.
Also some refactoring/improvements around the BindFun
in the pure unifier, which now can take the RHS type
into account.
Close #19106.
Close #19107.
Test case: partial-sigs/should_compile/T19106,
typecheck/should_compile/T19107
Diffstat (limited to 'compiler/GHC/Core/Coercion')
| -rw-r--r-- | compiler/GHC/Core/Coercion/Opt.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Coercion/Opt.hs b/compiler/GHC/Core/Coercion/Opt.hs index 108154e1c6..4353676af6 100644 --- a/compiler/GHC/Core/Coercion/Opt.hs +++ b/compiler/GHC/Core/Coercion/Opt.hs @@ -1005,7 +1005,7 @@ checkAxInstCo (AxiomInstCo ax ind cos) check_no_conflict _ [] = Nothing check_no_conflict flat (b@CoAxBranch { cab_lhs = lhs_incomp } : rest) -- See Note [Apartness] in GHC.Core.FamInstEnv - | SurelyApart <- tcUnifyTysFG (const BindMe) flat lhs_incomp + | SurelyApart <- tcUnifyTysFG alwaysBindFun flat lhs_incomp = check_no_conflict flat rest | otherwise = Just b |