[Git][ghc/ghc][wip/ghci-primcall] 6 commits: Refactor the treatment of loopy superclass dicts

Thu Jan 12 06:29:40 UTC 2023

Luite Stegeman pushed to branch wip/ghci-primcall at Glasgow Haskell Compiler / GHC

Commits:
aed1974e by Richard Eisenberg at 2023-01-11T08:30:42+00:00
Refactor the treatment of loopy superclass dicts

This patch completely re-engineers how we deal with loopy superclass
dictionaries in instance declarations. It fixes #20666 and #19690

The highlights are

* Recognise that the loopy-superclass business should use precisely
  the Paterson conditions.  This is much much nicer.  See
  Note [Recursive superclasses] in GHC.Tc.TyCl.Instance

* With that in mind, define "Paterson-smaller" in
  Note [Paterson conditions] in GHC.Tc.Validity, and the new
  data type `PatersonSize` in GHC.Tc.Utils.TcType, along with
  functions to compute and compare PatsonSizes

* Use the new PatersonSize stuff when solving superclass constraints
  See Note [Solving superclass constraints] in GHC.Tc.TyCl.Instance

* In GHC.Tc.Solver.Monad.lookupInInerts, add a missing call to
  prohibitedSuperClassSolve.  This was the original cause of #20666.

* Treat (TypeError "stuff") as having PatersonSize zero. See
  Note [Paterson size for type family applications] in GHC.Tc.Utils.TcType.

* Treat the head of a Wanted quantified constraint in the same way
  as the superclass of an instance decl; this is what fixes #19690.
  See GHC.Tc.Solver.Canonical Note [Solving a Wanted forall-constraint]
  (Thanks to Matthew Craven for this insight.)

  This entailed refactoring the GivenSc constructor of CtOrigin a bit,
  to say whether it comes from an instance decl or quantified constraint.

* Some refactoring way in which redundant constraints are reported; we
  don't want to complain about the extra, apparently-redundant
  constraints that we must add to an instance decl because of the
  loopy-superclass thing.  I moved some work from GHC.Tc.Errors to
  GHC.Tc.Solver.

* Add a new section to the user manual to describe the loopy
  superclass issue and what rules it follows.

- - - - -
300bcc15 by HaskellMouse at 2023-01-11T13:43:36-05:00
Parse qualified terms in type signatures

This commit allows qualified terms in type
signatures to pass the parser and to be cathced by renamer
with more informative error message. Adds a few tests.

Fixes #21605

- - - - -
964284fc by Simon Peyton Jones at 2023-01-11T13:44:12-05:00
Fix void-arg-adding mechanism for worker/wrapper

As #22725 shows, in worker/wrapper we must add the void argument
/last/, not first.  See GHC.Core.Opt.WorkWrap.Utils
Note [Worker/wrapper needs to add void arg last].

That led me to to study GHC.Core.Opt.SpecConstr
Note [SpecConstr needs to add void args first] which suggests the
opposite!  And indeed I think it's the other way round for SpecConstr
-- or more precisely the void arg must precede the "extra_bndrs".

That led me to some refactoring of GHC.Core.Opt.SpecConstr.calcSpecInfo.

- - - - -
f7ceafc9 by Krzysztof Gogolewski at 2023-01-11T22:36:59-05:00
Add 'docWithStyle' to improve codegen

This new combinator

docWithStyle :: IsOutput doc => doc -> (PprStyle -> SDoc) -> doc

let us remove the need for code to be polymorphic in HDoc
when not used in code style.

Metric Decrease:
    ManyConstructors
    T13035
    T1969

- - - - -
b3be0d18 by Simon Peyton Jones at 2023-01-11T22:37:35-05:00
Fix finaliseArgBoxities for OPAQUE function

We never do worker wrapper for OPAQUE functions, so we must
zap the unboxing info during strictness analysis.

This patch fixes #22502

- - - - -
4c8f5e7e by Luite Stegeman at 2023-01-12T15:29:08+09:00
Add PrimCallConv support to GHCi

This adds support for calling Cmm code from bytecode using the native
calling convention, allowing modules that use `foreign import prim`
to be loaded and debugged in GHCi.

This patch introduces a new `PRIMCALL` bytecode instruction and
a helper stack frame `stg_primcall`. The code is based on the
existing functionality for dealing with unboxed tuples in bytecode,
which has been generalised to handle arbitrary calls.

Fixes #22051

- - - - -

30 changed files:

- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/ByteCode/Instr.hs
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Cmm/CallConv.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/Reg.hs
- compiler/GHC/Core/InstEnv.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/TyCo/FVs.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Utils.hs
- compiler/GHC/Parser.y
- compiler/GHC/Rename/Env.hs
- compiler/GHC/Rename/HsType.hs
- compiler/GHC/Rename/Unbound.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm/Foreign.hs
- compiler/GHC/Tc/Deriv.hs
- compiler/GHC/Tc/Deriv/Infer.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Gen/HsType.hs
- compiler/GHC/Tc/Solver.hs
- compiler/GHC/Tc/Solver/Canonical.hs
- compiler/GHC/Tc/Solver/InertSet.hs
- compiler/GHC/Tc/Solver/Interact.hs
- compiler/GHC/Tc/Solver/Monad.hs

The diff was not included because it is too large.

View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d4725fabd68c4b8c7e575e8c662bdc20ad05167e...4c8f5e7ea1a59b88b79f64cd7a827414a134d137

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d4725fabd68c4b8c7e575e8c662bdc20ad05167e...4c8f5e7ea1a59b88b79f64cd7a827414a134d137
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