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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-11 23:49:27 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-13 10:57:03 +0100 |
| commit | 15b9bf4ba4ab47e6809bf2b3b36ec16e502aea72 (patch) | |
| tree | e2e7336c63e9b7130ba70f3551ff290d4a25184b /compiler/typecheck/TcRules.hs | |
| parent | d25cb61a1c2a135a2564143a332f8b2962f134bc (diff) | |
| download | haskell-15b9bf4ba4ab47e6809bf2b3b36ec16e502aea72.tar.gz | |
Improve typechecking of let-bindings
This major commit was initially triggered by #11339, but it spiraled
into a major review of the way in which type signatures for bindings
are handled, especially partial type signatures. On the way I fixed a
number of other bugs, namely
#12069
#12033
#11700
#11339
#11670
The main change is that I completely reorganised the way in which type
signatures in bindings are handled. The new story is in TcSigs
Note [Overview of type signatures]. Some specific:
* Changes in the data types for signatures in TcRnTypes:
TcIdSigInfo and new TcIdSigInst
* New module TcSigs deals with typechecking type signatures
and pragmas. It contains code mostly moved from TcBinds,
which is already too big
* HsTypes: I swapped the nesting of HsWildCardBndrs
and HsImplicitBndsrs, so that the wildcards are on the
oustide not the insidde in a LHsSigWcType. This is just
a matter of convenient, nothing deep.
There are a host of other changes as knock-on effects, and
it all took FAR longer than I anticipated :-). But it is
a significant improvement, I think.
Lots of error messages changed slightly, some just variants but
some modest improvements.
New tests
* typecheck/should_compile
* SigTyVars: a scoped-tyvar test
* ExPat, ExPatFail: existential pattern bindings
* T12069
* T11700
* T11339
* partial-sigs/should_compile
* T12033
* T11339a
* T11670
One thing to check:
* Small change to output from ghc-api/landmines.
Need to check with Alan Zimmerman
Diffstat (limited to 'compiler/typecheck/TcRules.hs')
| -rw-r--r-- | compiler/typecheck/TcRules.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/typecheck/TcRules.hs b/compiler/typecheck/TcRules.hs index 1b4826e1cd..4cfccb6bf0 100644 --- a/compiler/typecheck/TcRules.hs +++ b/compiler/typecheck/TcRules.hs @@ -145,7 +145,7 @@ tcRuleBndrs (L _ (RuleBndrSig (L _ name) rn_ty) : rule_bndrs) -- The tyvar 'a' is brought into scope first, just as if you'd written -- a::*, x :: a->a = do { let ctxt = RuleSigCtxt name - ; (id_ty, tvs, _) <- tcHsPatSigType ctxt rn_ty + ; (_ , tvs, id_ty) <- tcHsPatSigType ctxt rn_ty ; let id = mkLocalIdOrCoVar name id_ty -- See Note [Pattern signature binders] in TcHsType |