[Git][ghc/ghc][wip/int-index/emb-type] 11 commits: rnImports: var shouldn't import NoFldSelectors

Vladislav Zavialov (@int-index) gitlab at gitlab.haskell.org
Tue Jul 18 02:41:44 UTC 2023 


Vladislav Zavialov pushed to branch wip/int-index/emb-type at Glasgow Haskell Compiler / GHC


Commits:
c7bbad9a by sheaf at 2023-07-17T02:48:19-04:00
rnImports: var shouldn't import NoFldSelectors

In an import declaration such as

  import M ( var )

the import of the variable "var" should **not** bring into scope record
fields named "var" which are defined with NoFieldSelectors.
Doing so can cause spurious "unused import" warnings, as reported in
ticket #23557.

Fixes #23557

- - - - -
1af2e773 by sheaf at 2023-07-17T02:48:19-04:00
Suggest similar names in imports

This commit adds similar name suggestions when importing. For example

  module A where { spelling = 'o' }
  module B where { import B ( speling ) }

will give rise to the error message:

  Module ‘A’ does not export ‘speling’.
  Suggested fix: Perhaps use ‘spelling’

This also provides hints when users try to import record fields defined
with NoFieldSelectors.

- - - - -
654fdb98 by Alan Zimmerman at 2023-07-17T02:48:55-04:00
EPA: Store leading AnnSemi for decllist in al_rest

This simplifies the markAnnListA implementation in ExactPrint

- - - - -
22565506 by sheaf at 2023-07-17T21:12:59-04:00
base: add COMPLETE pragma to BufferCodec PatSyn

This implements CLC proposal #178, rectifying an oversight in the
implementation of CLC proposal #134 which could lead to spurious
pattern match warnings.

https://github.com/haskell/core-libraries-committee/issues/178
https://github.com/haskell/core-libraries-committee/issues/134

- - - - -
860f6269 by sheaf at 2023-07-17T21:13:00-04:00
exactprint: silence incomplete record update warnings

- - - - -
df706de3 by sheaf at 2023-07-17T21:13:00-04:00
Re-instate -Wincomplete-record-updates

Commit e74fc066 refactored the handling of record updates to use
the HsExpanded mechanism. This meant that the pattern matching inherent
to a record update was considered to be "generated code", and thus we
stopped emitting "incomplete record update" warnings entirely.

This commit changes the "data Origin = Source | Generated" datatype,
adding a field to the Generated constructor to indicate whether we
still want to perform pattern-match checking. We also have to do a bit
of plumbing with HsCase, to record that the HsCase arose from an
HsExpansion of a RecUpd, so that the error message continues to mention
record updates as opposed to a generic "incomplete pattern matches in case"
error.

Finally, this patch also changes the way we handle inaccessible code
warnings. Commit e74fc066 was also a regression in this regard, as we
were emitting "inaccessible code" warnings for case statements spuriously
generated when desugaring a record update (remember: the desugaring mechanism
happens before typechecking; it thus can't take into account e.g. GADT information
in order to decide which constructors to include in the RHS of the desugaring
of the record update).
We fix this by changing the mechanism through which we disable inaccessible
code warnings: we now check whether we are in generated code in
GHC.Tc.Utils.TcMType.newImplication in order to determine whether to
emit inaccessible code warnings.

Fixes #23520
Updates haddock submodule, to avoid incomplete record update warnings

- - - - -
1d05971e by sheaf at 2023-07-17T21:13:00-04:00
Propagate long-distance information in do-notation

The preceding commit re-enabled pattern-match checking inside record
updates. This revealed that #21360 was in fact NOT fixed by e74fc066.

This commit makes sure we correctly propagate long-distance information
in do blocks, e.g. in

```haskell
data T = A { fld :: Int } | B

f :: T -> Maybe T
f r = do
  a at A{} <- Just r
  Just $ case a of { A _ -> A 9 }
```

we need to propagate the fact that "a" is headed by the constructor "A"
to see that the case expression "case a of { A _ -> A 9 }" cannot fail.

Fixes #21360

- - - - -
bea0e323 by sheaf at 2023-07-17T21:13:00-04:00
Skip PMC for boring patterns

Some patterns introduce no new information to the pattern-match
checker (such as plain variable or wildcard patterns). We can thus
skip doing any pattern-match checking on them when the sole purpose
for doing so was introducing new long-distance information.

See Note [Boring patterns] in GHC.Hs.Pat.

Doing this avoids regressing in performance now that we do additional
pattern-match checking inside do notation.

- - - - -
ddcdd88c by Rodrigo Mesquita at 2023-07-17T21:13:36-04:00
Split GHC.Platform.ArchOS from ghc-boot into ghc-platform

Split off the `GHC.Platform.ArchOS` module from the `ghc-boot` package
into this reinstallable standalone package which abides by the PVP, in
part motivated by the ongoing work on `ghc-toolchain` towards runtime
retargetability.

- - - - -
b55a8ea7 by Sylvain Henry at 2023-07-17T21:14:27-04:00
JS: better implementation for plusWord64 (#23597)

- - - - -
643b1dae by Vladislav Zavialov at 2023-07-18T04:40:43+02:00
Visible forall in types of terms: Part 1

This patch implements part 1 of GHC Proposal #281,
introducing explicit `type` patterns and `type` arguments.

Summary of the changes:

1. New extension flag:
     RequiredTypeArguments

2. New user-facing syntax:
     `type p` patterns    (represented by EmbTyPat)
     `type e` expressions (represented by HsEmbTy)

3. Functions with required type arguments (visible forall)
   can now be defined and applied:
      idv :: forall a -> a -> a    -- signature   (relevant change: checkVdqOK in GHC/Tc/Validity.hs)
      idv (type a) (x :: a) = x    -- definition  (relevant change: tcPats in GHC/Tc/Gen/Pat.hs)
      x = idv (type Int) 42        -- usage       (relevant change: tcInstFun in GHC/Tc/Gen/App.hs)

4. template-haskell support:
      TH.TypeE corresponds to HsEmbTy
      TH.TypeP corresponds to EmbTyPat

5. Test cases and a new User's Guide section

Changes *not* included here are the t2t (term-to-type) transformation
and term variable capture; those belong to part 2.

- - - - -


30 changed files:

- compiler/GHC/Builtin/Names/TH.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Pat.hs
- compiler/GHC/Hs/Syn/Type.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore/Arrows.hs
- compiler/GHC/HsToCore/Errors/Ppr.hs
- compiler/GHC/HsToCore/Errors/Types.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/GuardedRHSs.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match.hs-boot
- compiler/GHC/HsToCore/Match/Constructor.hs
- compiler/GHC/HsToCore/Monad.hs
- compiler/GHC/HsToCore/Pmc.hs
- compiler/GHC/HsToCore/Pmc/Desugar.hs
- compiler/GHC/HsToCore/Pmc/Utils.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/HsToCore/Ticks.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/PostProcess.hs
- compiler/GHC/Rename/Bind.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Rename/Pat.hs
- compiler/GHC/Rename/Unbound.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2237142e2d19299a9e42ddc6272bbac01b2e1865...643b1dae62f41280850855aaaf29d3742c648874

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