[Git][ghc/ghc][wip/tc-lcl-env-refactor] 10 commits: Zonking monad transformers

Matthew Pickering (@mpickering) gitlab at gitlab.haskell.org
Wed May 17 10:01:12 UTC 2023 


Matthew Pickering pushed to branch wip/tc-lcl-env-refactor at Glasgow Haskell Compiler / GHC


Commits:
09ca44bc by sheaf at 2023-05-17T09:51:17+01:00
Zonking monad transformers

  - Introduce two zonking monad transformers, ZonkT and ZonkBndrT.
    ZonkT is a reader monad transformer over ZonkEnv.
    ZonkBndrT m is the codensity monad over ZonkT m.

    ZonkBndrT is used for computations that accumulate binders
    in the ZonkEnv.

  - Split up the zonking functions relating purely to types into
    GHC.Tc.Zonk.Type.

    This should allow us to introduce a slimmed-down zonking monad,
    which doesn't wrap the full TcM but a much smaller monad.
    This opens up the possibility of refactoring ErrCtxt to use this
    smaller zonking monad.

  - Refactor the remaining zonking functions to work over the monads
    ZonkTcM = ZonkT TcM and ZonkBndrTcM = ZonkBndrT TcM.

- - - - -
dd8a541d by Matthew Pickering at 2023-05-17T10:57:39+01:00
Use setSrcSpan rather than setLclEnv in solveForAll

In subsequent MRs (#23409) we want to remove the TcLclEnv argument from
a CtLoc. This MR prepares us for that by removing the one place where
the entire TcLclEnv is used, by using it more precisely to just set the
contexts source location.

Fixes #23390

- - - - -
be4380dc by Matthew Pickering at 2023-05-17T10:57:39+01:00
Big TcLclEnv and CtLoc refactoring

The overall goal of this refactoring is to reduce the dependency
footprint of the parser and syntax tree. Good reasons include:

- Better module graph parallelisability
- Make it easier to migrate error messages without introducing module loops
- Philosophically, there's not reason for the AST to depend on half the
  compiler.

One of the key edges which added this dependency was

> GHC.Hs.Expr -> GHC.Tc.Types (TcLclEnv)

As this in turn depending on TcM which depends on HscEnv and so on.

Therefore the goal of this patch is to move `TcLclEnv` out of
`GHC.Tc.Types` so that `GHC.Hs.Expr` can import TcLclEnv without
incurring a huge dependency chain.

The changes in this patch are:

* Move TcLclEnv from GHC.Tc.Types to GHC.Tc.Types.LclEnv
* Create new smaller modules for the types used in TcLclEnv
  New Modules:
  - GHC.Tc.Types.TcRef
  - GHC.Tc.Types.ErrCtxt
  - GHC.Tc.Types.TcIdSigInfo
  - GHC.Tc.Types.TcBinder
  - GHC.Tc.Types.TcTyThing
  - GHC.Tc.Types.TH
  - GHC.Tc.Types.LclEnv
  - GHC.Tc.Types.CtLocEnv
  - GHC.Tc.Errors.Types.PromotionErr

  Removed Boot File:
  - {-# SOURCE #-} GHC.Tc.Types

* Introduce TcLclCtxt, the part of the TcLclEnv which doesn't
  participate in restoreLclEnv.

* Replace TcLclEnv in CtLoc with specific CtLocEnv which is defined in
  GHC.Tc.Types.CtLocEnv. Use CtLocEnv in Implic and CtLoc to record the
  location of the implication and constraint.

By splitting up TcLclEnv from GHC.Tc.Types we allow GHC.Hs.Expr to no
longer depend on the TcM monad and all that entails.

* New modules for the LclEnv and all its basic parts
* CtLocEnv
* TcLclCtxt (setLclEnv vs restoreLclEnv)

- - - - -
6c85d227 by Matthew Pickering at 2023-05-17T10:57:39+01:00
Remove dependency of GHC.Tc.Utils.TcType on GHC.Driver.Session

This removes the usage of DynFlags from Tc.Utils.TcType  so that it no
longer depends on GHC.Driver.Session. In general we don't want anything
which is a dependency of Language.Haskell.Syntax to depend on
GHC.Driver.Session and removing this edge gets us closer to that goal.

- - - - -
740e3607 by Matthew Pickering at 2023-05-17T10:57:39+01:00
Move isIrrefutableHsPat to GHC.Rename.Utils and rename to isIrrefutableHsPatRn

This removes edge from GHC.Hs.Pat to GHC.Driver.Session, which makes
Language.Haskell.Syntax end up depending on GHC.Driver.Session.

- - - - -
29995bc3 by Matthew Pickering at 2023-05-17T10:57:39+01:00
Remove dependency of GHC.Tc.Types.Constraint on GHC.Driver.Session

- - - - -
289314c7 by Matthew Pickering at 2023-05-17T10:57:39+01:00
hole fit plugins: Split definition into own module

The hole fit plugins are defined in terms of TcM, a type we want to
avoid depending on from `GHC.Tc.Errors.Types`. By moving it into its own
module we can remove this dependency. It also simplifies the necessary
boot file.

- - - - -
fb47a80d by Matthew Pickering at 2023-05-17T10:57:39+01:00
Move GHC.Core.Opt.CallerCC Types into separate module

This allows `GHC.Driver.DynFlags` to depend on these types without
depending on CoreM and hence the entire simplifier pipeline.

We can also remove a hs-boot file with this change.

- - - - -
906061b7 by Matthew Pickering at 2023-05-17T10:57:39+01:00
Remove unecessary SOURCE import

- - - - -
f38c0422 by Matthew Pickering at 2023-05-17T10:57:39+01:00
testsuite: Accept new output for CountDepsAst and CountDepsParser tests

These are in a separate commit as the improvement to these tests is the
cumulative effect of the previous set of patches rather than just the
responsibility of the last one in the patchset.

- - - - -


30 changed files:

- compiler/GHC/Core/Opt/CallerCC.hs
- − compiler/GHC/Core/Opt/CallerCC.hs-boot
- + compiler/GHC/Core/Opt/CallerCC/Types.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Data/IOEnv.hs
- compiler/GHC/Driver/DynFlags.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Plugins.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Pat.hs
- compiler/GHC/Iface/Errors/Types.hs
- compiler/GHC/Plugins.hs
- compiler/GHC/Rename/Env.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Rename/Utils.hs
- compiler/GHC/Runtime/Eval.hs
- compiler/GHC/Runtime/Heap/Inspect.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Deriv/Infer.hs
- compiler/GHC/Tc/Deriv/Utils.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Errors/Hole.hs
- compiler/GHC/Tc/Errors/Hole.hs-boot
- compiler/GHC/Tc/Errors/Hole/FitTypes.hs
- − compiler/GHC/Tc/Errors/Hole/FitTypes.hs-boot
- + compiler/GHC/Tc/Errors/Hole/Plugin.hs
- + compiler/GHC/Tc/Errors/Hole/Plugin.hs-boot
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/672259755c94ef7bac2accfb3f52cb870f7e01b7...f38c04224b7782b3083cd10ca292a798c8967a83

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/672259755c94ef7bac2accfb3f52cb870f7e01b7...f38c04224b7782b3083cd10ca292a798c8967a83
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