It turns out that one can produce ill-formed Core by
combining `GeneralizedNewtypeDeriving`, `TypeInType`, and
`TypeFamilies`, as demonstrated in #14728. The root of the problem
is allowing the last parameter of a class to appear in a //kind// of
an associated type family, as our current approach to deriving
associated type family instances simply doesn't work well for that
situation.

Although it might be possible to properly implement this feature
today (see https://ghc.haskell.org/trac/ghc/ticket/14728#comment:3
for a sketch of how this might work), there does not currently exist
a performant implementation of the algorithm needed to accomplish
this. Until such an implementation surfaces, we will make this corner
case of `GeneralizedNewtypeDeriving` an error.

Test Plan: make test TEST="T14728a T14728b"

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14728

Differential Revision: https://phabricator.haskell.org/D4402

This change is present in 4.11.0.0.

Ryan Scott authored 7 years ago and David Feuer committed 7 years ago

Previously, we were skipping over `$tcUnit#` entirely when
wiring in `Typeable` tycons, resulting in #14811. Easily fixed.

Test Plan: make test TEST=T14811

Reviewers: bgamari, dfeuer

Reviewed By: dfeuer

Subscribers: dfeuer, rwbarton, thomie, carter

GHC Trac Issues: #14811

Differential Revision: https://phabricator.haskell.org/D4414

This is done for consistency. We usually call the package file the same name the
folder has.  The move into `utils` is done so that we can move the library into
`libraries/iserv` and the proxy into `utils/iserv-proxy` and then break the
`iserv.cabal` apart.  This will make building the cross compiler with TH
simpler, because we can build the library and proxy as separate packages.

Reviewers: bgamari, simonmar, goldfire, erikd

Reviewed By: simonmar

Subscribers: tdammers, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4377

GHC didn't inline `eqTypeRep`, presumably because it ended up
being too big. This was unfortunate because it produces a
`Maybe`, which will almost always be scrutinized immediately.

Split `eqTypeRep` into a worker and a tiny wrapper, and mark the
wrapper `INLINABLE`. This change actually seems to reduce Core size,
at least in a small test.

Reviewers: hvr, bgamari, mpickering

Reviewed By: mpickering

Subscribers: mpickering, rwbarton, thomie, carter

GHC Trac Issues: #14790

Differential Revision: https://phabricator.haskell.org/D4405

Alp Mestanogullari authored 7 years ago and Moritz Angermann committed 7 years ago

The make build system appears to be doing a bit of magic in order to supply
the profiled flavours of libHSrts and libCffi, as they're not advertised in
the 'extra-library-flavours' field of rts.cabal.in. This patch explicitly
advertises _p and _thr_p flavours of the RTS library and libCffi, but only
when the RTS is configured with the (newly introduced) 'profiling' flag.

This is necessary for Hadrian, as a branch (soon to be merged) does away with
ghc-cabal and relies just on Cabal to get package information. Without this
patch, Cabal can never inform us that _p and _thr_p flavours should be
built (and registered in the package db) as well, which obviously prevents us
from building a profiled GHC.

Reviewers: bgamari, erikd, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4409

cabal introduces SPDX identifier, and as such we need to change the
BSD3 license name. Also the >= qualifier is no longer prefered.

Test Plan: ./validate

Reviewers: bgamari, erikd, simonmar

Reviewed By: bgamari

Subscribers: alpmestan, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4406

Reviewers: bgamari, erikd, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4393

Reviewers: bgamari, hvr

Reviewed By: bgamari

Subscribers: erikd, hvr, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4378

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

 * Fix missing code example in changelog for 8.4.1

 * List 'setEnv' as opposite of 'getEnv'

   It seems best to direct users to use 'System.Environment.setEnv'
   rather than 'System.Posix.Env.putEnv'. This is due to 'setEnv' being
   located in the same module as 'getEnv' and my virtue of working on
   Windows platform, whereas 'putEnv' does not have that quality because
   it's part of the 'unix' package.

 * Reflect in docs the fact that 'readMVar' is not a composition of
   'takeMVVar' and 'putMVar' any more

Empty GADTs data declarations can't be identified in type checker. This
patch adds additional checks in parser and raise a parse error when
encounter empty GADTs declarations but extension `GADTs` is not enabled.

Only empty declarations are checked in parser to avoid affecting
existing
error messages related to missing GADTs extension.

This patch should fix issue 8258.

Signed-off-by: HE, Tao <sighingnow@gmail.com>

Test Plan: make test TEST="T8258 T8258NoGADTs"

Reviewers: bgamari, mpickering, alanz, RyanGlScott

Reviewed By: bgamari, RyanGlScott

Subscribers: adamse, RyanGlScott, rwbarton, thomie, mpickering, carter

GHC Trac Issues: #8258

Differential Revision: https://phabricator.haskell.org/D4350

This patch includes two changes:

1. Move cost centre collection from `SCCfinal` to `CorePrep`, to be able
   to collect cost centres in unfoldings. `CorePrep` drops unfoldings, so
   that's the latest stage in the compilation pipeline for this.

   After this change `SCCfinal` no longer collects all cost centres, but
   it still generates & collects CAF cost centres + updates cost centre
   stacks of `StgRhsClosure` and `StgRhsCon`s.

   This fixes #5889.

2. Initialize cost centre stack fields of `StgRhs` in `coreToStg`. With
   this we no longer need to update cost centre stack fields in
   `SCCfinal`, so that module is removed.

   Cost centre initialization explained in Note [Cost-centre
   initialization plan].

   Because with -fcaf-all we need to attach a new cost-centre to each
   CAF, `coreTopBindToStg` now returns `CollectedCCs`.

Test Plan: validate

Reviewers: simonpj, bgamari, simonmar

Reviewed By: simonpj, bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #5889

Differential Revision: https://phabricator.haskell.org/D4325

Now that `($)` is representation-polymorphic, `($!)` should
surely follow suit.

Reviewers: hvr, bgamari, simonpj

Reviewed By: bgamari, simonpj

Subscribers: simonpj, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4382

`NO_PROMOTE_THUNKS` is never defined

Reviewers: hvr, bgamari, RyanGlScott

Reviewed By: RyanGlScott

Subscribers: RyanGlScott, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4401

When finishing up an implication constraint, it's a bit tricky to
decide which Derived constraints to retain (for error reporting) and
which to discard.  I got this wrong in commit
   f20cf982
   (Remove wc_insol from WantedConstraints)

The particular problem in Trac #14763 was that we were reporting as an
error a fundep-generated constraint
  (ex ~ T)
where 'ex' is an existentially-bound variable in a pattern match.
But this isn't really an error at all.

This patch fixes the problem. Indeed, since I had to understand
this rather tricky code, I took the opportunity to clean it up
and document better.  See
  isDroppableCt :: Ct -> Bool
and Note [Dropping derived constraints]

I also removed wl_deriv altogether from the WorkList data type.  It
was there in the hope of gaining efficiency by not even processing
lots of derived constraints, but it has turned out that most derived
constraints (notably equalities) must be processed anyway; see
Note [Prioritise equalities] in TcSMonad.

The two are coupled because to decide which constraints to put in
wl_deriv I was using another variant of isDroppableCt.  Now it's much
simpler -- and perhaps even more efficient too.

Douglas Wilson authored 7 years ago and Tamar Christina committed 7 years ago

Summary: See definition of PRINTF above the change

Reviewers: bgamari, erikd, simonmar, Phyx

Reviewed By: Phyx

Subscribers: Phyx, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4392

This was an oversight from 2671cccd
as it wasn't obvious to assume one would go the trouble to manually
construct the pkg-db entries... :-)

This patch fixes the redundant superclass expansion
in Trac #14774.

The main change is to fix TcInterac.solveOneFromTheOther, so
that it does not prefer a work-item with a binding if that binding
transitively depends on the inert item we are comparing it with.

Explained in Note [Replacement vs keeping] in TcInert, esp
item (c) of the "Constraints coming from the same level" part.

To make this work I refactored out a new function
TcEvidence.findNeededEvVars, which was previously buried
inside TcSimplify.neededEvVars.

I added quite a few more comments and signposts about superclass
expansion.

In prelRules we had:

  tx_con_tte :: DynFlags -> AltCon -> AltCon
  tx_con_tte _      DEFAULT      = DEFAULT
  tx_con_tte dflags (DataAlt dc)
    | tag == 0  = DEFAULT   -- See Note [caseRules for tagToEnum]
    | otherwise = LitAlt (mkMachInt dflags (toInteger tag))

The tag==0 case is totally wrong, and led directly to Trac #14768.

See "Beware" in Note [caseRules for tagToEnum] (in the patch).

Easily fixed, though!

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

Reviewers: bgamari, erikd, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4390

Reviewers: bgamari, erikd, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4386

The original implementation generates a list of SDoc then concatenates
them using `hcat`. For memory optimization, we can transform the given
literal string into escaped string the construct SDoc directly.

This optimization will decreate the memory allocation when there's big
literal strings in haskell code, see Trac #14741.

Signed-off-by: HE, Tao <sighingnow@gmail.com>

Reviewers: bgamari, mpickering, simonpj

Reviewed By: simonpj

Subscribers: simonpj, rwbarton, thomie, carter

GHC Trac Issues: #14741

Differential Revision: https://phabricator.haskell.org/D4384

Edward Z. Yang authored 7 years ago and Ben Gamari committed 7 years ago

See comment in Packages for more details.

Fixes #14717.

Signed-off-by: Edward Z. Yang <ezyang@fb.com>

Test Plan: validate

Reviewers: snoyberg, taylorfausak, bgamari

Reviewed By: snoyberg, taylorfausak, bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14717

Differential Revision: https://phabricator.haskell.org/D4376

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

Test Plan: Validate

Reviewers: erikd, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4374

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

Test Plan: Validate

Reviewers: erikd, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4373

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

Test Plan: ./validate

Reviewers: goldfire, bgamari, simonmar

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4367

I've explained most of the rationale in a new Note.
I'd happily add a test for this, but the difference is only
visible in run time, allocations remain more or less the same.

FWIW running `generateModules` from #14693 with DEPTH=16, WIDTH=30
finishes in `23s` before, and `11s` after.

Test Plan: ./validate

Reviewers: simonpj, simonmar, bgamari

Reviewed By: simonpj

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14693

Differential Revision: https://phabricator.haskell.org/D4369

* Clarify the representation of sums without fields.
* Try to improve language, clarity, and examples.

Fixes #14752

Reviewers: osa1, bgamari

Reviewed By: osa1

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14752

Differential Revision: https://phabricator.haskell.org/D4379

Trac #14226 noted that the C-- CBE pass frequently fails to
common up semantically identical blocks due to the differences in local
register naming. These patches fixed this by making the pass consider
equality up to alpha-renaming.

However, the new logic failed to consider the possibility that local
register naming *may* matter across multiple blocks. This lead to the
regression #14754. I'll need to do a bit of thinking on a proper
solution to this but in the meantime I'm reverting all four patches.

This reverts commit a27056f9.
This reverts commit 6f990c54.
This reverts commit 9aa73892.
This reverts commit 7920a7d9.

Commit 193664d4 added a
special caseRule for `dataToTag`, but this transformation completely
broke when `dataToTag` was applied to somewith with a type headed by
a data family, leading to #14680. For now at least, the simplest
solution is to simply not apply this transformation when the type is
headed by a data family.

Test Plan: make test TEST=T14680

Reviewers: simonpj, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14680

Differential Revision: https://phabricator.haskell.org/D4371

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

GCC's __sync primitives apparently "usually" imply a full barrier,
meaning they can be used to emulate the more precise C11 atomics albeit
with a loss of efficiency. This restores compatibility with GCC 4.4.

This partially reverts commit 59de2909.

Test Plan: Validate on Centos

Reviewers: hvr, simonmar, trommler

Subscribers: rwbarton, thomie, erikd, carter

GHC Trac Issues: #14244

Differential Revision: https://phabricator.haskell.org/D4364

Reviewers: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4340