Sebastian Graf authored 1 year ago and Marge Bot committed 1 year ago

A minor improvement to pretty-printing

Krzysztof Gogolewski authored 1 year ago and Marge Bot committed 1 year ago

Lint messages were saying "in the body of letrec" even for non-recursive
let.

I've also renamed BodyOfLetRec to BodyOfLet in stg, since there's no
separate letrec.

sheaf authored 1 year ago and Marge Bot committed 1 year ago

This patch changes how we perform representation-polymorphism checking
for primops (and other wired-in Ids such as coerce).
When instantiating the primop, we check whether each type variable
is required to instantiated to a concrete type, and if so we create a
new concrete metavariable (a ConcreteTv) instead of a simple MetaTv.
(A little subtlety is the need to apply the substitution obtained from
instantiating to the ConcreteTvOrigins, see
Note [substConcreteTvOrigin] in GHC.Tc.Utils.TcMType.)

This allows us to prevent representation-polymorphism in non-argument
position, as that is required for some of these primops.

We can also remove the logic in tcRemainingValArgs, except for
the part concerning representation-polymorphic unlifted newtypes.
The function has been renamed rejectRepPolyNewtypes; all it does now
is reject unsaturated occurrences of representation-polymorphic newtype
constructors when the representation of its argument isn't a concrete
RuntimeRep (i.e. still a PHASE 1 FixedRuntimeRep check).
The Note [Eta-expanding rep-poly unlifted newtypes] in GHC.Tc.Gen.Head
gives more explanation about a possible path to PHASE 2, which would be
in line with the treatment for primops taken in this patch.

We also update the Core Lint check to handle this new framework. This
means Core Lint now checks representation-polymorphism in continuation
position like needed for catch#.

Fixes #21906

-------------------------
Metric Increase:
    LargeRecord
-------------------------

Add JS backend adapted from the GHCJS project by Luite Stegeman.

Some features haven't been ported or implemented yet. Tests for these
features have been disabled with an associated gitlab ticket.

Bump array submodule

Work funded by IOG.

Co-authored-by: Jeffrey Young <jeffrey.young@iohk.io>
Co-authored-by: Luite Stegeman <stegeman@gmail.com>
Co-authored-by: Josh Meredith <joshmeredith2008@gmail.com>

Necessary for newer cross-compiling backends (JS, Wasm) that don't
support TH yet.

sheaf authored 2 years ago and Marge Bot committed 2 years ago

The testsuite output now contains diagnostic codes, so many tests need
to be updated at once.
We decided it was best to keep the diagnostic codes in the testsuite
output, so that contributors don't inadvertently make changes to the
diagnostic codes.

Krzysztof Gogolewski authored 2 years ago and Marge Bot committed 2 years ago

- Remove mkHeteroCoercionType, sdocImpredicativeTypes, isStateType (unused),
  isCoVar_maybe (duplicated by getCoVar_maybe)
- Replace a few occurrences of voidPrimId with (# #).
  void# is a deprecated synonym for the unboxed tuple.
- Use showSDoc in :show linker.
  This makes it consistent with the other :show commands

Yiyun Liu authored 2 years ago and Marge Bot committed 2 years ago

This patch removes the TCvSubst data type and instead uses Subst as
the environment for both term and type level substitution. This
change is partially motivated by the existential type proposal,
which will introduce types that contain expressions and therefore
forces us to carry around an "IdSubstEnv" even when substituting for
types. It also reduces the amount of code because "Subst" and
"TCvSubst" share a lot of common operations. There isn't any
noticeable impact on performance (geo. mean for ghc/alloc is around
0.0% but we have -94 loc and one less data type to worry abount).

Currently, the "TCvSubst" data type for substitution on types is
identical to the "Subst" data type except the former doesn't store
"IdSubstEnv". Using "Subst" for type-level substitution means there
will be a redundant field stored in the data type. However, in cases
where the substitution starts from the expression, using "Subst" for
type-level substitution saves us from having to project "Subst" into a
"TCvSubst". This probably explains why the allocation is mostly even
despite the redundant field.

The patch deletes "TCvSubst" and moves "Subst" and its relevant
functions from "GHC.Core.Subst" into "GHC.Core.TyCo.Subst".
Substitution on expressions is still defined in "GHC.Core.Subst" so we
don't have to expose the definition of "Expr" in the hs-boot file that
"GHC.Core.TyCo.Subst" must import to refer to "IdSubstEnv" (whose
codomain is "CoreExpr"). Most functions named fooTCvSubst are renamed
into fooSubst with a few exceptions (e.g. "isEmptyTCvSubst" is a
distinct function from "isEmptySubst"; the former ignores the
emptiness of "IdSubstEnv"). These exceptions mainly exist for
performance reasons and will go away when "Expr" and "Type" are
mutually recursively defined (we won't be able to take those
shortcuts if we can't make the assumption that expressions don't
appear in types).

Co-Authored-By: Andre Marianiello <andremarianiello@users.noreply.github.com>

This commit implements proposal 302: \cases - Multi-way lambda
expressions.

This adds a new expression heralded by \cases, which works exactly like
\case, but can match multiple apats instead of a single pat.

Updates submodule haddock to support the ITlcases token.

Closes #20768

Vladislav Zavialov authored 3 years ago and Marge Bot committed 3 years ago

This enables GHC to report more parse errors in a single pass.

sheaf authored 3 years ago and Marge Bot committed 3 years ago

  This patch does the following two things:

    1. Fix the check in Core Lint to properly throw an error when it
       comes across Float#/Double# literal patterns. The check
       was incorrect before, because it expected the type to be
       Float/Double instead of Float#/Double#.

    2. Add an error in the parser when the user writes a floating-point
       literal pattern such as `case x of { 2.0## -> ... }`.

  Fixes #21115

sheaf authored 3 years ago and Marge Bot committed 3 years ago

  Don't instantiate type variables for :type in
  `GHC.Tc.Gen.App.tcInstFun`, to avoid inconsistently instantianting
  `r1` but not `r2` in the type

    forall {r1} (a :: TYPE r1) {r2} (b :: TYPE r2). ...

  This fixes #21088.

  This patch also changes the primop pretty-printer to ensure
  that we put all the inferred type variables first. For example,
  the type of reallyUnsafePtrEquality# is now

    forall {l :: Levity} {k :: Levity}
           (a :: TYPE (BoxedRep l))
           (b :: TYPE (BoxedRep k)).
      a -> b -> Int#

  This means we avoid running into issue #21088 entirely with
  the types of primops. Users can still write a type signature where
  the inferred type variables don't come first, however.

  This change to primops had a knock-on consequence, revealing that
  we were sometimes performing eta reduction on keepAlive#.
  This patch updates tryEtaReduce to avoid eta reducing functions
  with no binding, bringing it in line with tryEtaReducePrep,
  and thus fixing #21090.

sheaf authored 3 years ago and Marge Bot committed 3 years ago

We were not looking through floatable ticks when collecting arguments in
Core Lint, which caused `checkCanEtaExpand` to fail on something like:

```haskell
reallyUnsafePtrEquality
  = \ @a ->
      (src<loc> reallyUnsafePtrEquality#)
        @Lifted @a @Lifted @a
```

We fix this by using `collectArgsTicks tickishFloatable` instead of
`collectArgs`, to be consistent with the behaviour of eta expansion
outlined in Note [Eta expansion and source notes] in GHC.Core.Opt.Arity.

Fixes #21152.

This patch adds a check to Core Lint, checkCanEtaExpand,
which ensures that primops and other wired-in functions with
no binding such as unsafeCoerce#, oneShot, rightSection...
can always be eta-expanded, by checking that the remaining
argument types have a fixed RuntimeRep.

Two subtleties came up:

  - the notion of arity in Core looks through newtypes, so we may
    need to unwrap newtypes in this check,
  - we want to avoid calling hasNoBinding on something whose unfolding
    we are in the process of linting, as this would cause a loop;
    to avoid this we add some information to the Core Lint environment
    that holds this information.

Fixes #20480