[Git][ghc/ghc][wip/T18235] 7 commits: Add link to GHC's wiki in the GHC API header
Ryan Scott
gitlab at gitlab.haskell.org
Wed Jun 10 09:26:18 UTC 2020
Ryan Scott pushed to branch wip/T18235 at Glasgow Haskell Compiler / GHC
Commits:
9b607671 by Takenobu Tani at 2020-06-09T08:05:46-04:00
Add link to GHC's wiki in the GHC API header
This adds a URL to point to GHC's wiki in the GHC API header.
Newcomers could easily find more information from the GHC API's
web like [1].
[1]: Current version, https://ghc.gitlab.haskell.org/ghc/doc/libraries/ghc-8.11.0.20200604/index.html
[skip ci]
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72c7fe9a by Ryan Scott at 2020-06-09T08:06:24-04:00
Make GADT constructors adhere to the forall-or-nothing rule properly
Issue #18191 revealed that the types of GADT constructors don't quite
adhere to the `forall`-or-nothing rule. This patch serves to clean up
this sad state of affairs somewhat. The main change is not in the
code itself, but in the documentation, as this patch introduces two
sections to the GHC User's Guide:
* A "Formal syntax for GADTs" section that presents a BNF-style
grammar for what is and isn't allowed in GADT constructor types.
This mostly exists to codify GHC's existing behavior, but it also
imposes a new restriction that addresses #18191: the outermost
`forall` and/or context in a GADT constructor is not allowed to be
surrounded by parentheses. Doing so would make these
`forall`s/contexts nested, and GADTs do not support nested
`forall`s/contexts at present.
* A "`forall`-or-nothing rule" section that describes exactly what
the `forall`-or-nothing rule is all about. Surprisingly, there was
no mention of this anywhere in the User's Guide up until now!
To adhere the new specification in the "Formal syntax for GADTs"
section of the User's Guide, the following code changes were made:
* A new function, `GHC.Hs.Type.splitLHsGADTPrefixTy`, was introduced.
This is very much like `splitLHsSigmaTy`, except that it avoids
splitting apart any parentheses, which can be syntactically
significant for GADT types. See
`Note [No nested foralls or contexts in GADT constructors]` in
`GHC.Hs.Type`.
* `ConDeclGADTPrefixPs`, an extension constructor for `XConDecl`, was
introduced so that `GHC.Parser.PostProcess.mkGadtDecl` can return
it when given a prefix GADT constructor. Unlike `ConDeclGADT`,
`ConDeclGADTPrefixPs` does not split the GADT type into its argument
and result types, as this cannot be done until after the type is
renamed (see `Note [GADT abstract syntax]` in `GHC.Hs.Decls` for why
this is the case).
* `GHC.Renamer.Module.rnConDecl` now has an additional case for
`ConDeclGADTPrefixPs` that (1) splits apart the full `LHsType` into
its `forall`s, context, argument types, and result type, and
(2) checks for nested `forall`s/contexts. Step (2) used to be
performed the typechecker (in `GHC.Tc.TyCl.badDataConTyCon`) rather
than the renamer, but now the relevant code from the typechecker
can simply be deleted.
One nice side effect of this change is that we are able to give a
more accurate error message for GADT constructors that use visible
dependent quantification (e.g., `MkFoo :: forall a -> a -> Foo a`),
which improves the stderr in the `T16326_Fail6` test case.
Fixes #18191. Bumps the Haddock submodule.
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a47e6442 by Ryan Scott at 2020-06-10T03:39:12-04:00
Always use rnImplicitBndrs to bring implicit tyvars into scope
This implements a first step towards #16762 by changing the renamer
to always use `rnImplicitBndrs` to bring implicitly bound type
variables into scope. The main change is in `rnFamInstEqn` and
`bindHsQTyVars`, which previously used _ad hoc_ methods of binding
their implicit tyvars.
There are a number of knock-on consequences:
* One of the reasons that `rnFamInstEqn` used an _ad hoc_ binding
mechanism was to give more precise source locations in
`-Wunused-type-patterns` warnings. (See
https://gitlab.haskell.org/ghc/ghc/issues/16762#note_273343 for an
example of this.) However, these warnings are actually a little
_too_ precise, since implicitly bound type variables don't have
exact binding sites like explicitly bound type variables do.
A similar problem existed for
"`Different names for the same type variable`" errors involving
implicit tyvars bound by `bindHsQTyVars`.
Therefore, we simply accept the less precise (but more accurate)
source locations from `rnImplicitBndrs` in `rnFamInstEqn` and
`bindHsQTyVars`. See
`Note [Source locations for implicitly bound type variables]` in
`GHC.Rename.HsType` for the full story.
* In order for `rnImplicitBndrs` to work in `rnFamInstEqn`, it needs
to be able to look up names from the parent class (in the event
that we are renaming an associated type family instance). As a
result, `rnImplicitBndrs` now takes an argument of type
`Maybe assoc`, which is `Just` in the event that a type family
instance is associated with a class.
* Previously, GHC kept track of three type synonyms for free type
variables in the renamer: `FreeKiTyVars`, `FreeKiTyVarsDups`
(which are allowed to contain duplicates), and
`FreeKiTyVarsNoDups` (which contain no duplicates). However, making
is a distinction between `-Dups` and `-NoDups` is now pointless, as
all code that returns `FreeKiTyVars{,Dups,NoDups}` will eventually
end up being passed to `rnImplicitBndrs`, which removes duplicates.
As a result, I decided to just get rid of `FreeKiTyVarsDups` and
`FreeKiTyVarsNoDups`, leaving only `FreeKiTyVars`.
* The `bindLRdrNames` and `deleteBys` functions are now dead code, so
I took the liberty of removing them.
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24879129 by Takenobu Tani at 2020-06-10T03:39:59-04:00
Clarify leaf module names for new module hierarchy
This updates comments only.
This patch replaces leaf module names according to new module
hierarchy [1][2] as followings:
* Expand leaf names to easily find the module path:
for instance, `Id.hs` to `GHC.Types.Id`.
* Modify leaf names according to new module hierarchy:
for instance, `Convert.hs` to `GHC.ThToHs`.
* Fix typo:
for instance, `GHC.Core.TyCo.Rep.hs` to `GHC.Core.TyCo.Rep`
See also !3375
[1]: https://gitlab.haskell.org/ghc/ghc/-/wikis/Make-GHC-codebase-more-modular
[2]: https://gitlab.haskell.org/ghc/ghc/issues/13009
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92de9e25 by Ömer Sinan Ağacan at 2020-06-10T03:41:07-04:00
rts: Remove unused GET_ENTRY closure macro
This macro is not used and got broken in the meantime, as ENTRY_CODE was
deleted.
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87102928 by Ömer Sinan Ağacan at 2020-06-10T03:41:50-04:00
Fix -fkeep-cafs flag name in users guide
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e1b40627 by Ryan Scott at 2020-06-10T05:25:05-04:00
Use HsForAllTelescope to avoid inferred, visible foralls
Currently, `HsForAllTy` permits the combination of `ForallVis` and
`Inferred`, but you can't actually typecheck code that uses it
(e.g., `forall {a} ->`). This patch refactors `HsForAllTy` to use a
new `HsForAllTelescope` data type that makes a type-level distinction
between visible and invisible `forall`s such that visible `forall`s
do not track `Specificity`. That part of the patch is actually quite
small; the rest is simply changing consumers of `HsType` to
accommodate this new type.
Fixes #18235. Bumps the `haddock` submodule.
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30 changed files:
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Ppr/Expr.hs
- compiler/GHC/CmmToAsm.hs
- compiler/GHC/CmmToAsm/CFG.hs
- compiler/GHC/CmmToAsm/Dwarf.hs
- compiler/GHC/CmmToAsm/Monad.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/SPARC/Ppr.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/CmmToLlvm/Data.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/FVs.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/FloatIn.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/CoreToByteCode.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2467b737431619097a2b24c409e63388f6bd4e7d...e1b4062713cca5e6522b19c5c3baca63321bdd9d
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2467b737431619097a2b24c409e63388f6bd4e7d...e1b4062713cca5e6522b19c5c3baca63321bdd9d
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