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A silly mistake in `gen_Show_binds` was causing derived
`Show` instances for empty data types to case on the precedence
argument instead of the actual value being showed.

Test Plan: make test TEST=drv-empty-data

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14692

Differential Revision: https://phabricator.haskell.org/D4328

(cherry picked from commit 0074a08e)

This adds support for the bit deposit and extraction operations provided
by the BMI and BMI2 instruction set extensions on modern amd64 machines.

Implement x86 code generator for pdep and pext.  Properly initialise
bmiVersion field.

pdep and pext test cases

Fix pattern match for pdep and pext instructions

Fix build of pdep and pext code for 32-bit architectures

Test Plan: Validate

Reviewers: austin, simonmar, bgamari, angerman

Reviewed By: bgamari

Subscribers: trommler, carter, angerman, thomie, rwbarton, newhoggy

GHC Trac Issues: #14206

Differential Revision: https://phabricator.haskell.org/D4236

(cherry picked from commit f8557696)

This is an attempt at clarifying the docs for HasCallStack in both the
user guide and libraries/base/GHC/Stack/Types.hs. The example used right
now is built around an hypothetical 'error' function that doesn't itself
print call stacks, and the fact that this doesn't hold makes it all
confusing, see #14635.

Reviewers: hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14635

Differential Revision: https://phabricator.haskell.org/D4317

- Cabal-2.2 uses SPDX license identifiers, so I had to update
  `cabal-version: 2.1` packages `license: BSD3` to
  `license: BSD-3-Clause`
- `ghc-cabal` used old ReadP parsec, now it uses `parsec` too
- InstalledPackageInfo pretty-printing have changed a little,
  fields with default values aren't printed. This can be changed in
  `Cabal` still, but I haven't found problems with omitting them.

Note: `BSD-3-Clause` is parsed as "name = BSD, version = 3" by old
parser (because 3-Clause looks like version 3 with tag Clause).
If you see *"BSD-3" is not a valid license*, then something is using
old parser still.

Fixes #9885.

(cherry picked from commit 5d6e0806c690ac1958e4cbf609bc6b18048fb761)

It turns out that `Convert` was recklessly leaving off
parentheses in two places:

* Negative numeric literals
* Patterns in lambda position

This patch fixes it by adding three new functions, `isCompoundHsLit`,
`isCompoundHsOverLit`, and `isCompoundPat`, and using them in the
right places in `Convert`. While I was in town, I also sprinkled
`isCompoundPat` among some `Pat`-constructing functions in `HsUtils`
to help avoid the likelihood of this problem happening in other
places. One of these places is in `TcGenDeriv`, and sprinkling
`isCompountPat` there fixes #14682

Test Plan: make test TEST="T14681 T14682"

Reviewers: alanz, goldfire, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14681, #14682

Differential Revision: https://phabricator.haskell.org/D4323

(cherry picked from commit 575c009d)

On Windows GHC enforces currently that the real executable is named
ghc.exe/ghc-stage[123].exe.

I don't see a good reason why this is neccessary.
This patch removes this restriction and fixes #14652

Test Plan: ci

Reviewers: bgamari, Phyx

Reviewed By: Phyx

Subscribers: Phyx, rwbarton, thomie, carter

GHC Trac Issues: #14652

Differential Revision: https://phabricator.haskell.org/D4296

(cherry picked from commit 1bf70b20)

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14653

Differential Revision: https://phabricator.haskell.org/D4305

(cherry picked from commit 2feed118)

This implements SPJ's suggestion on the ticket (#14273). We find the
relevant constraints (ones that whose free unification variables are all
mentioned in the type of the hole), and then clone the free unification
variables of the hole and the relevant constraints. We then add a
subsumption constraints and run the simplifier, and then check whether
all the constraints were solved.

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: RyanGlScott, rwbarton, thomie, carter

GHC Trac Issues: #14273

Differential Revision: https://phabricator.haskell.org/D4315

(cherry picked from commit 1e14fd3e)

Previously, GHC was pretty-printing left-section holes
incorrectly and not parsing right-sectioned holes at all. This patch
fixes both problems.

Test Plan: make test TEST=T14590

Reviewers: bgamari, simonpj

Reviewed By: simonpj

Subscribers: simonpj, rwbarton, thomie, mpickering, carter

GHC Trac Issues: #14590

Differential Revision: https://phabricator.haskell.org/D4273

(cherry picked from commit 4d41e921)

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

(cherry picked from commit fb1f0a46)

Substitute RanlibCmd for consistency, and other configure cleanups that
should have no effect

The other commands are so substituted. Maybe we don't need ranlib at
all, and the configure snippet can be removed all together, but that
can always be done later.

Reviewers: bgamari, hvr, angerman

Reviewed By: bgamari, angerman

Subscribers: rwbarton, thomie, erikd, carter

Differential Revision: https://phabricator.haskell.org/D4286

(cherry picked from commit 8de89305)

Trac #14646 happened because we forgot to parenthesize `forall` types to
the left of an arrow. This simple patch fixes that.

Test Plan: make test TEST=T14646

Reviewers: alanz, goldfire, bgamari

Reviewed By: alanz

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14646

Differential Revision: https://phabricator.haskell.org/D4298

(cherry picked from commit f380115c)

This patch moves the "ok_unfolding" test
   from  CoreOpt.joinPointBinding_maybe
   to    OccurAnal.decideJoinPointHood

Previously the occurrence analyser was deciding to make
something a join point, but the simplifier was reversing
that decision, which made the decision about /other/ bindings
invalid.

Fixes Trac #14650.

(cherry picked from commit 66ff794f)

This is a pure refactoring.  Use HsConDetails to implement
HsPatSynDetails, instead of defining a whole new data type.
Less code, fewer types, all good.

(cherry picked from commit 584cbd4a)

This recent patch
    commit 1577908f
    Author: Simon Peyton Jones <simonpj@microsoft.com>
    Date:   Tue Jan 9 16:20:46 2018 +0000

        Fix two more bugs in partial signatures

        These were shown up by Trac #14643

failed validation for typecheck/should_run/T10846
(Reported in Trac #14658.)

The fix is simple.

(cherry picked from commit f3f90a07)

These were shown up by Trac #14643

Bug 1: if we had a single partial signature for
two functions
   f, g :: forall a. _ -> a
then we made two different SigTvs but with the sane Name.
This was jolly confusing and ultimately led to deeply bogus
results with Any's appearing in the resulting program. Yikes.
Fix: clone the quantified variables in TcSigs.tcInstSig (as
indeed its name suggests).

Bug 2: we were not eliminating duplicate/superclass constraints
in the partial signatures of a mutually recursive group.

Easy to fix: we are already doing dup/superclass elim in
TcSimplify.decideQuantification.  So we move the partial-sig
constraints there too.

(cherry picked from commit 1577908f)

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.

(cherry picked from commit be1ca0e4)

Trac #13032 pointed out that we sometimes generate unused
bindings for Givens, and (worse still) we can't always discard
them later (we don't drop a case binding unless we can prove
that the scrutinee is non-bottom.

It looks as if this may be a major reason for the performace
problems in #14338 (see comment:29).

This patch fixes the problem at source, by pruning away all the
dead Givens.  See Note [Delete dead Given evidence bindings]

Remarkably, compiler allocation falls by 23% in
perf/compiler/T12227!

I have not confirmed whether this change actualy helps with

(cherry picked from commit 954cbc7c)

This rather subtle patch fixes Trac #14584.  The problem was
that we'd allowed a coercion, bound in a nested scope, to escape
into an outer scope.

The main changes are

* TcSimplify.floatEqualities takes more care when floating
  equalities to make sure we don't float one out that mentions
  a locally-bound coercion.
  See Note [What prevents a constraint from floating]

* TcSimplify.emitResidualConstraints (which emits the residual
  constraints in simplifyInfer) now avoids burying the constraints
  for escaping CoVars inside the implication constraint.

* Since I had do to this stuff with CoVars, I moved the
  fancy footwork about not quantifying over CoVars from
  TcMType.quantifyTyVars to its caller
  TcSimplify.decideQuantifiedTyVars.  I think its other
  callers don't need to worry about all this CoVar stuff.

This turned out to be surprisigly tricky, and took me a solid
day to get right.  I think the result is reasonably neat, though,
and well documented with Notes.

(cherry picked from commit f5cf9d1a)

In fixing Trac #14584 I found that it would be /much/ more
convenient if a "hole" in a coercion (much like a unification
variable in a type) acutally had a CoVar associated with it
rather than just a Unique.  Then I can ask what the free variables
of a coercion is, and get a set of CoVars including those
as-yet-un-filled in holes.

Once that is done, it makes no sense to stuff coercion holes
inside UnivCo.  They were there before so we could know the
kind and role of a "hole" coercion, but once there is a CoVar
we can get that info from the CoVar.  So I removed HoleProv
from UnivCoProvenance and added HoleCo to Coercion.

In summary:

* Add HoleCo to Coercion and remove HoleProv from UnivCoProvanance

* Similarly in IfaceCoercion

* Make CoercionHole have a CoVar in it, not a Unique

* Make tyCoVarsOfCo return the free coercion-hole variables
  as well as the ordinary free CoVars.  Similarly, remember
  to zonk the CoVar in a CoercionHole

We could go further, and remove CoercionHole as a distinct type
altogther, just collapsing it into HoleCo.  But I have not done
that yet.

(cherry picked from commit a492af06)

This fixes Trac #14479.  Not difficult.

See Note [Quantification and partial signatures] Wrinkle 4,
in TcSimplify.

(cherry picked from commit 72938f58)

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]

(cherry picked from commit 8361b2c5)

This refactoring

* Renames kcHsTyVarBndrs to kcLHsQTyVars,
  which is more truthful. It is only used in getInitialKind.

* Pulls out bind_telescope from that function, and calls it
  kcLHsTyVarBndrs, again to reflect its argument

* Uses the new kcLHsTyVarBndrs in kcConDecl, where the old
  function was wild overkill.

There should not be any change in behaviour

(cherry picked from commit de204409)

when read notifications are requested, too (#13903)
Signed-off-by: Matthias Treydte <mt@waldheinz.de>

KQueue: Drop Bits/FiniteBits instances for Filter as they are really
constants whose bits should not be fiddled with
Signed-off-by: Matthias Treydte <mt@waldheinz.de>

Reviewers: austin, hvr, bgamari

Reviewed By: bgamari

Subscribers: gridaphobe, kazu_yamamoto, rwbarton, thomie

GHC Trac Issues: #13903

Differential Revision: https://phabricator.haskell.org/D3692

(cherry picked from commit 6c3eafb3)

Summary:
`GeneralizedNewtypeDeriving` generates calls to `coerce`
which take visible type arguments. These types must be produced by
way of `typeToLHsType`, which converts a `Type` to an `LHsType`.
However, `typeToLHsType` was leaving off important kind information
when a `Type` contained a poly-kinded tycon application, leading to
incorrectly generated code in #14579.

This fixes the issue by tweaking `typeToLHsType` to generate
explicit kind signatures for tycon applications. This makes the
generated code noisier, but at least the program from #14579 now
works correctly.

Test Plan: make test TEST=T14579

Reviewers: simonpj, bgamari

Reviewed By: simonpj

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14579

Differential Revision: https://phabricator.haskell.org/D4264

(cherry picked from commit 649e7772)

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

(cherry picked from commit 1bd91a7a)

Summary: To be in line with the other typeNatTyCons

Reviewers: bgamari, RyanGlScott

Reviewed By: RyanGlScott

Subscribers: RyanGlScott, rwbarton, thomie, carter

GHC Trac Issues: #14632

Differential Revision: https://phabricator.haskell.org/D4284

(cherry picked from commit fb78b0d2)

Commit fa8035e3 added `Div`
and `Mod` type families to `GHC.TypeNats`. However, they did not add
the corresponding fixities! Currently, we have that both `div` and
`mod` (at the value level) are `infixl 7`, so we should adopt the
same fixities for the type-level `Div` and `Mod` as well.

Test Plan: It compiles

Reviewers: hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #14640

Differential Revision: https://phabricator.haskell.org/D4291

(cherry picked from commit 303106d5)

Commit 714bebff removed
a check in the bytecode compiler that caught illegal uses of unboxed
tuples (and now sums) in case alternatives, which causes the program
in #14608 to panic. This restores the check (using modern,
levity-polymorphic vocabulary).

Test Plan: make test TEST=T14608

Reviewers: hvr, bgamari, dfeuer, simonpj

Reviewed By: dfeuer, simonpj

Subscribers: simonpj, rwbarton, thomie, carter

GHC Trac Issues: #14608

Differential Revision: https://phabricator.haskell.org/D4276

(cherry picked from commit ecff651f)

This calls out to the Win32 API `GetTempFileName` to generate
a temporary file. Using `uUnique = 0` guarantees that the file
we get back is unique and the file is "reserved" by creating it.

Test Plan:
./validate

I can't think of any sensible tests that shouldn't run for a while
to verify. So the example in #10731 was ran for a while and no
collisions in new code

Reviewers: hvr, bgamari, erikd

Reviewed By: bgamari

Subscribers: RyanGlScott, rwbarton, thomie, carter

GHC Trac Issues: #10731

Differential Revision: https://phabricator.haskell.org/D4278

(cherry picked from commit 46287af0)

Previously, we were inexplicably not applying an instantiating
substitution to arguments in non-prenex types. It's amazing this
has been around for so long! I guess there aren't a lot of non-prenex
types around.

test case: typecheck/should_fail/T14618

(cherry picked from commit 722a6584)

(cherry picked from commit e237e1f1)

Split-sections unfortunately isn't yet working.

Prior to 8.0.2 MultiWayIf syntax required that the -> token be indented relative
to the guard. See #10807.

[skip ci]

(cherry picked from commit 4d99a665)

[skip ci]

(cherry picked from commit 00565677)