Summary:
The `HsType` pretty-printer does not automatically insert
parentheses where necessary for type applications, so a function
`isCompoundHsType` was created in D4056 towards this purpose.
However, it was not used in as many places as it ought to be,
resulting in #14578.

Test Plan: make test TEST=T14578

Reviewers: alanz, bgamari, simonpj

Reviewed By: alanz, simonpj

Subscribers: simonpj, rwbarton, thomie, carter

GHC Trac Issues: #14578

Differential Revision: https://phabricator.haskell.org/D4266

[skip ci]

(cherry picked from commit 00565677)

This is a tiny refactoring that removes one of the calls
to mkStatePrimTy, in service to Trac #14596

Triggered by thinking about Trac #14596, I found that runRW#
does not need to be a "magic" wired-in Id, now that we have
levity polymorphism.

This patch stops it being wired-in.

Simon Marlow authored 7 years ago and David Feuer committed 7 years ago

Test Plan: validate

Reviewers: bgamari, niteria, erikd, dfeuer

Reviewed By: dfeuer

Subscribers: Yuras, dfeuer, rwbarton, thomie, carter

GHC Trac Issues: #14497

Differential Revision: https://phabricator.haskell.org/D4254

This patch fixes Trac #14998, where we eventually decided that
the existential type variables of the signature of a pattern
synonym should not scope over the pattern synonym.

See Note [Pattern synonym existentials do not scope] in TcPatSyn.

This fixes Trac #14591

I took the opportunity to delete the dead code isMonadCompExpr

The fix for #11203 prohibits duplicate SigTvs in non-CUSK kind
signatures by checking for duplicates after type inference is
done. This works well. GHC also checks for duplicate SigTvs
after working with partial type signatures (another place where
SigTvs arise). However, neither fix eliminates this whole class
of problems (because doing so would be heavier than we would
like). So, this comment adds a warning to users of newSigTyVar
to be aware of problems with duplicates.

This patch fixes an outright bug in tcDataKindSig, shown up in Trac
of a data type declaration.  See Note [TyConBinders for the result kind
signature of a data type]

I also took the opportunity to elminate the DataKindCheck argument
and data type from tcDataKindSig, instead moving the check to the
call site, which is easier to understand.

(cherry picked from commit 15b2b959)

(cherry picked from commit fdccc666)

carlostome authored 7 years ago and Ben Gamari committed 7 years ago

We filter the complete patterns given in a COMPLETE set to only those that
subsume the type we are matching. Otherwise we end up introducing an ill-typed
equation into the overlap checking, provoking a crash. This was the cause of
Trac #14135.

Reviewers: austin, bgamari, mpickering, gkaracha, simonpj, RyanGlScott,
carlostome

Reviewed By: bgamari

Subscribers: carter, dfeuer, RyanGlScott, goldfire, rwbarton, thomie

GHC Trac Issues: #14135

Differential Revision: https://phabricator.haskell.org/D3981

Trac #14554 showed up an outright bug in the unflattening code in
TcFlatten.  I was filling in a coercion with the wrong coercion (a Syn
in the wrong place).  Result: "Bad coercion hole" assertion failures,
and Core Lint Errors.

Easily fixed, and the code is simpler too.

The typechecker has the invariant that every type should be well-kinded
as it stands, without zonking.  See Note [The well-kinded type invariant]
in TcType.

That invariant was not being upheld, which led to Trac #14174.  I fixed
part of it, but T14174a showed that there was more.  This patch finishes
the job.

* See Note [The tcType invariant] in TcHsType, which articulates an
  invariant that was very nearly, but not quite, true.  One place that
  falisified it was the HsWildCardTy case of tc_hs_type, so I fixed that.

* mkNakedCastTy now makes no attempt to eliminate casts; indeed it cannot
  lest it break Note [The well-kinded type invariant].  The prior comment
  suggested that it was crucial for performance but happily it seems not
  to be. The extra Refls are eliminated by the zonker.

* I found I could tidy up TcHsType.instantiateTyN and instantiateTyUntilN
  by eliminating one of its parameters.  That led to a cascade of minor
  improvements in TcTyClsDecls. Hooray.

Bytes allocated has fallen by around 5%. I think this due
to some of my recent refactoring of the typechecker, but
I'm not certain about exactly which change did it.

Good though!

Two things here:

* While debugging Trac #14561 I found it hard to understand
  ghcPrimIds and magicIds in MkId.  This patch adds more
  structure and comments.

* I also discovered that ($) no longer needs to be a wiredInId
  because we now have levity polymorphism.  So I took dollarId
  out of MkId; and gave it a levity-polymorphic type in GHC.Base

This bug was shown up by Trac #14561. The deguarer carefully
detects unsaturated and levity-polymorphic uses of primops,
but not of things like unsafeCoerce#.

The fix is simple: see Note [Levity-polymorphic Ids] in Id.

This refactoring has no change in behaviour but makes the
structure clearer

This adds a regression test for the original program in #14040.

This does not fix #14040 entirely, though, as the program in
https://ghc.haskell.org/trac/ghc/ticket/14040#comment:2 still
panics, so there is more work to be done there.

Niklas Hambüchen authored 7 years ago and Ben Gamari committed 7 years ago

Reviewers: bgamari, austin, hvr, dfeuer

Reviewed By: dfeuer

Subscribers: syd, dfeuer, rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D4012

Niklas Hambüchen authored 7 years ago and Ben Gamari committed 7 years ago

Reviewers: bgamari, Phyx, austin, hvr, simonmar

Reviewed By: bgamari

Subscribers: syd, rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D4041

* Add a new flag, `-fignore-optim-changes`, allowing them to avoid
  recompilation if the only changes are to the `-O` level or to
  flags controlling optimizations.

* When `-fignore-optim-changes` is *off*, recompile when optimization
  flags (e.g., `-fno-full-laziness`) change. Previously, we ignored
  these unconditionally when deciding whether to recompile a module.

Reviewers: austin, bgamari, simonmar

Reviewed By: simonmar

Subscribers: duog, carter, simonmar, rwbarton, thomie

GHC Trac Issues: #13604

Differential Revision: https://phabricator.haskell.org/D4123

Simon Marlow authored 7 years ago and Ben Gamari committed 7 years ago

open() can sometimes take a long time, for example on NFS or FUSE
filesystems.  We recently had a case where open() was taking multiple
seconds to return for a (presumably overloaded) FUSE filesystem, which
blocked GC and caused severe issues.

Test Plan: validate

Reviewers: niteria, bgamari, nh2, hvr, erikd

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #13296

Differential Revision: https://phabricator.haskell.org/D4239

Ben Gamari authored 7 years ago and Ben Gamari committed 7 years ago

This was presumably a vestige of the days when the profiled RTS couldn't
run threaded. Fixes #14545.

Test Plan: simonmar

Reviewers: erikd, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14545

Differential Revision: https://phabricator.haskell.org/D4245

Matthew Pickering authored 7 years ago and Ben Gamari committed 7 years ago

There appears to be no benefit in inlining this function.
If you turn up the unfolding threshold a lot then it eventually
inlines which produces a bit unoptimisable program.

Reviewers: hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4246

This information was present in the ghc wiki but not the user guide.
[skip ci]

Test Plan: None

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: RyanGlScott, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4250

Nathan Collins authored 7 years ago and Ben Gamari committed 7 years ago

This fixes Issue #12372: documentation for Control.Monad.guard not
useful after AMP.

Reviewers: hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4258

Because in recent RHEL7 suddenly locales like `bokmål` pop up, which
screw up reading-in of ASCII strings a line later. This additional
criterion reliably eliminates those unicode characters.

This patch fixes two bugs in the treatment of SigTvs at the
kind level:

- We should always generalise them, never default them
  (Trac #14555, #14563)

- We should check if they get unified with each other
  (Trac #11203)

Both are described in TcHsType
   Note [Kind generalisation and SigTvs]