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| author | Gert-Jan Bottu <gertjan.bottu@kuleuven.be> | 2020-03-23 09:36:28 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-05-21 12:11:31 -0400 |
| commit | a9311cd53d33439e8fe79967ba5fb85bcd114fec (patch) | |
| tree | 2254ef735a24f9de8d192203a3c6f4871a8b6ae9 /compiler/GHC/Tc/Errors | |
| parent | 55f0e783d234af103cf4e1d51cd31c99961c5abe (diff) | |
| download | haskell-a9311cd53d33439e8fe79967ba5fb85bcd114fec.tar.gz | |
Explicit Specificity
Implementation for Ticket #16393.
Explicit specificity allows users to manually create inferred type variables,
by marking them with braces.
This way, the user determines which variables can be instantiated through
visible type application.
The additional syntax is included in the parser, allowing users to write
braces in type variable binders (type signatures, data constructors etc).
This information is passed along through the renamer and verified in the
type checker.
The AST for type variable binders, data constructors, pattern synonyms,
partial signatures and Template Haskell has been updated to include the
specificity of type variables.
Minor notes:
- Bumps haddock submodule
- Disables pattern match checking in GHC.Iface.Type with GHC 8.8
Diffstat (limited to 'compiler/GHC/Tc/Errors')
| -rw-r--r-- | compiler/GHC/Tc/Errors/Hole.hs | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/compiler/GHC/Tc/Errors/Hole.hs b/compiler/GHC/Tc/Errors/Hole.hs index c764d7d3e3..0639e79073 100644 --- a/compiler/GHC/Tc/Errors/Hole.hs +++ b/compiler/GHC/Tc/Errors/Hole.hs @@ -441,10 +441,12 @@ pprHoleFit (HFDC sWrp sWrpVars sTy sProv sMs) (HoleFit {..}) = where name = getName hfCand tyApp = sep $ zipWithEqual "pprHoleFit" pprArg vars hfWrap where pprArg b arg = case binderArgFlag b of - Specified -> text "@" <> pprParendType arg - -- Do not print type application for inferred - -- variables (#16456) - Inferred -> empty + -- See Note [Explicit Case Statement for Specificity] + (Invisible spec) -> case spec of + SpecifiedSpec -> text "@" <> pprParendType arg + -- Do not print type application for inferred + -- variables (#16456) + InferredSpec -> empty Required -> pprPanic "pprHoleFit: bad Required" (ppr b <+> ppr arg) tyAppVars = sep $ punctuate comma $ |