[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 3 commits: implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)

[Marge Bot (@marge-bot)]

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC


Commits:
9b1595c8 by Ross Paterson at 2022-09-27T14:12:01-04:00
implement proposal 106 (Define Kinds Without Promotion) (fixes #6024)

includes corresponding changes to haddock submodule

- - - - -
2b71cfab by Andreas Klebinger at 2022-09-28T08:17:18-04:00
Apply some tricks to speed up core lint.

Below are the noteworthy changes and if given their impact on compiler
allocations for a type heavy module:

* Use the oneShot trick on LintM
* Use a unboxed tuple for the result of LintM: ~6% reduction
* Avoid a thunk for the result of typeKind in lintType: ~5% reduction
* lint_app: Don't allocate the error msg in the hot code path: ~4%
  reduction
* lint_app: Eagerly force the in scope set: ~4%
* nonDetCmpType: Try to short cut using reallyUnsafePtrEquality#: ~2%
* lintM: Use a unboxed maybe for the `a` result: ~12%
* lint_app: make go_app tail recursive to avoid allocating the go function
            as heap closure: ~7%
* expandSynTyCon_maybe: Use a specialized data type

For a less type heavy module like nofib/spectral/simple compiled with
-O -dcore-lint allocations went down by ~24% and compile time by ~9%.

-------------------------
Metric Decrease:
    T1969
-------------------------

- - - - -
0db6b616 by sheaf at 2022-09-28T08:17:20-04:00
matchLocalInst: do domination analysis

When multiple Given quantified constraints match a Wanted, and there is
a quantified constraint that dominates all others, we now pick it
to solve the Wanted.

See Note [Use only the best matching quantified constraint].

For example:

  [G] d1: forall a b. ( Eq a, Num b, C a b  ) => D a b
  [G] d2: forall a  .                C a Int  => D a Int
  [W] {w}: D a Int

When solving the Wanted, we find that both Givens match, but we pick
the second, because it has a weaker precondition, C a Int, compared
to (Eq a, Num Int, C a Int). We thus say that d2 dominates d1;
see Note [When does a quantified instance dominate another?].

This domination test is done purely in terms of superclass expansion,
in the function GHC.Tc.Solver.Interact.impliedBySCs. We don't attempt
to do a full round of constraint solving; this simple check suffices
for now.

Fixes #22216 and #22223

- - - - -


30 changed files:

- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/DataCon.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/Type.hs
- + compiler/GHC/Data/Unboxed.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/PostProcess.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Solver/InertSet.hs
- compiler/GHC/Tc/Solver/Interact.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/TyCl.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/Types/Origin.hs
- compiler/GHC/ThToHs.hs
- compiler/GHC/Types/Error/Codes.hs
- compiler/GHC/Types/TyThing.hs
- compiler/GHC/Utils/Misc.hs
- compiler/Language/Haskell/Syntax/Decls.hs
- compiler/ghc.cabal.in
- docs/users_guide/9.6.1-notes.rst
- docs/users_guide/exts/data_kinds.rst


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/cc3878008b0adf15264386347638421c9b5168ab...0db6b61621319bc5d5329e2217fb009644b86fa5

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/cc3878008b0adf15264386347638421c9b5168ab...0db6b61621319bc5d5329e2217fb009644b86fa5
You're receiving this email because of your account on gitlab.haskell.org.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-commits/attachments/20220928/1d7e4aaf/attachment.html>