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| author | Simon Peyton Jones <simon.peytonjones@gmail.com> | 2023-03-06 10:50:47 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2023-03-22 01:03:08 -0400 |
| commit | 926ad6ded5cb5e8162914e746ee001fc8d1658ec (patch) | |
| tree | 0a324771f624518d6f6e12413ba32ce4d4699171 /compiler/GHC/Tc/Validity.hs | |
| parent | ea24360d0548c905b6b2427b5cdcb82d3cd296ae (diff) | |
| download | haskell-926ad6ded5cb5e8162914e746ee001fc8d1658ec.tar.gz | |
Be more careful about quantification
This MR is driven by #23051. It does several things:
* It is guided by the generalisation plan described in #20686.
But it is still far from a complete implementation of that plan.
* Add Note [Inferred type with escaping kind] to GHC.Tc.Gen.Bind.
This explains that we don't (yet, pending #20686) directly
prevent generalising over escaping kinds.
* In `GHC.Tc.Utils.TcMType.defaultTyVar` we default RuntimeRep
and Multiplicity variables, beause we don't want to quantify over
them. We want to do the same for a Concrete tyvar, but there is
nothing sensible to default it to (unless it has kind RuntimeRep,
in which case it'll be caught by an earlier case). So we promote
instead.
* Pure refactoring in GHC.Tc.Solver:
* Rename decideMonoTyVars to decidePromotedTyVars, since that's
what it does.
* Move the actual promotion of the tyvars-to-promote from
`defaultTyVarsAndSimplify` to `decidePromotedTyVars`. This is a
no-op; just tidies up the code. E.g then we don't need to
return the promoted tyvars from `decidePromotedTyVars`.
* A little refactoring in `defaultTyVarsAndSimplify`, but no
change in behaviour.
* When making a TauTv unification variable into a ConcreteTv
(in GHC.Tc.Utils.Concrete.makeTypeConcrete), preserve the occ-name
of the type variable. This just improves error messages.
* Kill off dead code: GHC.Tc.Utils.TcMType.newConcreteHole
Diffstat (limited to 'compiler/GHC/Tc/Validity.hs')
| -rw-r--r-- | compiler/GHC/Tc/Validity.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Tc/Validity.hs b/compiler/GHC/Tc/Validity.hs index f088a7e6ab..d9df4913bc 100644 --- a/compiler/GHC/Tc/Validity.hs +++ b/compiler/GHC/Tc/Validity.hs @@ -475,7 +475,7 @@ This is not OK: we get MkT :: forall l. T @l :: TYPE (BoxedRep l) which is ill-kinded. -For ordinary /user-written type signatures f :: blah, we make this +For ordinary /user-written/ type signatures f :: blah, we make this check as part of kind-checking the type signature in tcHsSigType; see Note [Escaping kind in type signatures] in GHC.Tc.Gen.HsType. |