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The warning for reference:
```
rts/RaiseAsync.c: In function ‘throwToMsg’:

rts/SMPClosureOps.h:65:0: error:
     error: inlining failed in call to ‘lockClosure’: call is unlikely
and code size would grow

rts/RaiseAsync.c:305:0: error:  error: called from here

rts/SMPClosureOps.h:65:0: error:
     error: inlining failed in call to ‘lockClosure’: call is unlikely
and code size would grow
```

This warning triggers on `gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-16)`
and it doesn't trigger with new GCCs.

Test Plan: build ghc/rts

Reviewers: bgamari, simonmar, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2353

Provoked by Trac #11948, this patch adds a new warning to GHC

  -Wsimplifiable-class-constraints

It warns if you write a class constraint in a type signature that
can be simplified by an existing instance declaration.  Almost always
this means you should simplify it right now; type inference is very
fragile without it, as #11948 shows.

I've put the warning as on-by-default, but I suppose that if there are
howls of protest we can move it out (as happened for -Wredundant-constraints.

It actually found an example of an over-complicated context in CmmNode.

Quite a few tests use these weird contexts to trigger something else,
so I had to suppress the warning in those.

The 'haskeline' library has a few occurrences of the warning (which
I think should be fixed), so I switched it off for that library in
warnings.mk.

The warning itself is done in TcValidity.check_class_pred.

HOWEVER, when type inference fails we get a type error; and the error
suppresses the (informative) warning.  So as things stand, the warning
only happens when it doesn't cause a problem.  Not sure what to do
about this, but this patch takes us forward, I think.

Most notably, this update pulls in documentation improvements
and several INLINE pragmas for significant performance gains[1].

 [1]: https://groups.google.com/d/msg/haskell-cafe/SUKtkDI84EE/fXMBd-jNDQAJ

Makes the needed changes to make RemoteGHCi work on Windows.
The approach passes OS Handles areound instead of the Posix Fd
as on Linux.

The reason is that I could not find any real documentation about
the behaviour of Windows w.r.t inheritance and Posix FDs.

The implementation with Fd did not seem to be able to find the Fd
in the child process. Instead I'm using the much better documented
approach of passing inheriting handles.

This requires a small modification to the `process` library.
https://github.com/haskell/process/pull/52

Test Plan: ./validate On Windows x86_64

Reviewers: thomie, erikd, bgamari, simonmar, austin, hvr

Reviewed By: simonmar

Subscribers: #ghc_windows_task_force

Differential Revision: https://phabricator.haskell.org/D1836

GHC Trac Issues: #11100

Also, `binary` now is almost warning free
(except for inlinePerformIO deprecation warnings)

/cc @kolmodin

This is the designated release to go with GHC 8.0.1

/cc @AshleyYakeley

So far only `time` (fixed upstream already though) and `xhtml` still require
`-Wno-tabs`, so let's apply that warning suppression flag only there.

This also updates the haskeline submodule to pull in a tab-fix

This is the designated release to go with GHC 8.0.1

This release doesn't need any warning-suppression flags anymore, so
remove those from mk/warnings.mk

/cc @foxik

And fix a redundant constraint warning in a test that requires
primitive.

Cabal is currently warning free. So let's drop the `-w`-flags.

/cc @dcoutts

This replaces some occurences of `-f(no-)warn` with the new `-W`-aliases
introduced via 2206fa8c / #11218, in cases which are guaranteed
to be invoked with recent enough GHC (i.e. the stage1+ GHC).

After this commit, mostly the compiler and the testsuite remain using
`-f(wo-)warn...` because the compiler needs to be bootstrappable with
older GHCs, while for the testsuite it's convenient to be able to quickly
compare the behavior to older GHCs (which may not support the new flags yet).

The compiler-part can be updated to use the new flags once GHC 8.3 development
starts.

Reviewed By: quchen

Differential Revision: https://phabricator.haskell.org/D1637

This makes use of the new facility introduced via
14d0f7f1 which allows
to have certain flags passed only to the non-bootstrapping
GHC. This is needed because sometimes we can't assume the
existence of a certain flag in the bootstrapping compiler
which was only added recently to GHC HEAD.

This also updates the haddock submodule to fix a few
remaining noncanonical instance definitions.

Differential Revision: https://phabricator.haskell.org/D1571

* Add stage specific versions of SRC_HC_OPTS. These are currently only
  used for -Werror. The previous combination of GhcStage2HcOpts and
  GhcLibHcOpts didn't apply to utils/*.

* Add stage specific versions of SRC_HC_WARNING_OPTS. These will later be
  used for new warning supression flags that should not be passed to the
  bootstrap compiler.

* Move -Wall (and -Werror) related code back to mk/warnings.mk, where it
  was before 987d5427. Now all warning related code is nicely together.
  Include mk/warnings.mk after mk/custom-settings.mk to make this work.

Reviewed By: bgamari, hvr

Differential Revision: https://phabricator.haskell.org/D1536

Problem: 'SRC_HC_OPTS += -Wall' in 'mk/warnings.mk' was getting
overwritten by 'SRC_HC_OPTS = ...' in 'mk/flavours/*.mk'.

It didn't affect the compiler or most other libraries, because most
.cabal files define 'ghc-options: -Wall'.

Bug introduced in commit
2c24fd70, when moving validate settings
from 'mk/validate-settings.mk' to 'mk/flavours/validate.mk'.

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D1425

Test Plan: using remote validate

Reviewers: austin, hvr, simonpj, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1117

This patch suppresses them until they are fixed

libraries/parallel/Control/Parallel/Strategies.hs:513:2: warning:
    Rule "parList/rseq" may never fire
      because ‘rseq’ might inline first
    Probable fix: add an INLINE[n] or NOINLINE[n] pragma for ‘rseq’

libraries/parallel/Control/Parallel/Strategies.hs:582:1: warning:
    Rule "evalBuffer/rseq" may never fire
      because ‘rseq’ might inline first
    Probable fix: add an INLINE[n] or NOINLINE[n] pragma for ‘rseq’

libraries/parallel/Control/Parallel/Strategies.hs:583:1: warning:
    Rule "parBuffer/rseq" may never fire
      because ‘rseq’ might inline first
    Probable fix: add an INLINE[n] or NOINLINE[n] pragma for ‘rseq’

GHC now warns if rules compete, so that it's not predicatable
which will work and which will not. E.g.

{-# RULES
  f (g x) = ...
  g True  = ...
  #-}

If we had (f (g True)) it's not clear which rule would fire.

This showed up fraility in the libraries.

* Suppress warnigns in Control.Arrow, Control.Category for class
  methods. At the moment we simply don't have a good way to write a
  RULE with a class method in the LHS.  See Trac #1595.  Arrow and
  Category attempt to do so; I have silenced the complaints with
  -fno-warn-inline-rule-shadowing, but it's not a great solution.

* Adjust the NOINLINE pragma on 'GHC.Base.map' to account for the
  map/coerce rule

* Adjust the rewrite rules in Enum, especially for the "literal 1"
  case.  See Note [Enum Integer rules for literal 1].

* Suppress warnings for 'bytestring' e.g.
   libraries/bytestring/Data/ByteString.hs:895:1: warning:
      Rule "ByteString specialise break (x==)" may never fire
        because rule "Class op ==" for ‘==’ might fire first
      Probable fix: add phase [n] or [~n] to the competing rule

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate on 7.6

Reviewers: austin, goldfire

Subscribers: bgamari, thomie

Differential Revision: https://phabricator.haskell.org/D885

Summary:
This commit adds stage 1 support for Template Haskell
quoting, e.g. [| ... expr ... |], which is useful
for authors of quasiquoter libraries that do not actually
need splices.  The TemplateHaskell extension now does not
unconditionally fail; it only fails if the renamer encounters
a splice that it can't run.

In order to make sure the referenced data structures
are consistent, template-haskell is now a boot library.
There are some minor BC changes to template-haskell to make it boot
on GHC 7.8.

Note for reviewer: big diff changes are simply code
being moved out of an ifdef; there was no other substantive
change to that code.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, goldfire

Subscribers: bgamari, thomie

Differential Revision: https://phabricator.haskell.org/D876

GHC Trac Issues: #10382

Revert "Quick fix: drop base bound on template-haskell."

This reverts commit 3c70ae03.

Revert "Always do polymorphic typed quote check, c.f. #10384"

This reverts commit 9a43b2c1.

Revert "RnSplice's staging test should be applied for quotes in stage1."

This reverts commit eb0ed403.

Revert "Split off quotes/ from th/ for tests that can be done on stage1 compiler."

This reverts commit 21c72e7d.

Revert "Support stage 1 Template Haskell (non-quasi) quotes, fixes #10382."

This reverts commit 28257cae.

Summary:
This commit adds stage 1 support for Template Haskell
quoting, e.g. [| ... expr ... |], which is useful
for authors of quasiquoter libraries that do not actually
need splices.  The TemplateHaskell extension now does not
unconditionally fail; it only fails if the renamer encounters
a splice that it can't run.

In order to make sure the referenced data structures
are consistent, template-haskell is now a boot library.

In the following patches, there are:

    - A few extra safety checks which should be enabled
      in stage1
    - Separation of the th/ testsuite into quotes/ which
      can be run on stage1

Note for reviewer: big diff changes are simply code
being moved out of an ifdef; there was no other substantive
change to that code.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, austin, goldfire

Subscribers: bgamari, thomie

Differential Revision: https://phabricator.haskell.org/D876

GHC Trac Issues: #10382

The default validate settings currently disable some warnings in the
libraries. This patch moves those settings to a new file called
`mk/warnings.mk`, and applies them also to normal builds.

Through uncommenting a line in build.mk, developers can now build with
-Werror.

-Werror is not the default, because:
* We can not guarantee that the build is warning free on platforms we
  don't run regularly run validate (as part of continuous integration
  systems), and we still want the build to go through on those
  platforms.
* quoting rwbarton on irc > "I think -Werror by default has come up in
  the past and the argument was that it is too annoying when you are
  doing nontrivial development"

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D785

This patch affects libraries, and requires a submodule update.

Some other libraries, maintained by others, have redundant constraints,
namely:
           containers
           haskeline
           transformers
           binary

I have suppressed the redundant-constraint warnings by settings in
           validate-settings.mk
(in this commit)

This drops a couple of `-fno-warn-*` which seem to have become obsolete
by now.

Moreover, with the cleaned up settings `./validate` passes with GHC
7.10.1 as bootstrap compiler.

This redoes part of 475dd93e which was reversed in 452d6aa9 after
breaking validate on windows.

updated to handle `-fwarn-trustworthy-safe`.

This pulls in the new `Generic`-based `-XDefaultSignature`-based default
implementation for `rnf`[1], and will be interesting to use in combination
with the soon to be merged `-XDeriveAnyClass` extension.

This requires updating several other submodules as well in order
to relax the upper bound on `deepseq` and/or in a few cases to
avoid relying on the default method implementation of `rnf`:

 - `Cabal`
 - `bytestring`
 - `containers`
 - `parallel`
 - `process`
 - `time`

 [1]: http://permalink.gmane.org/gmane.comp.lang.haskell.libraries/23031

Update submodule haskell2010, haskell98, hoop, hpc and stm to fix new
warnings.

Summary:
The option is not needed (it was only intended to override Debian's default)
and causes an error if the host ghc's mingw is too old (which the script
does not detect).

Fixes T9727

Reviewers: austin

Reviewed By: austin

Subscribers: thomie, carter, simonmar

Differential Revision: https://phabricator.haskell.org/D373

GHC Trac Issues: #9727

Summary:
This revision enables -fwarn-tabs by default and add a suppression
flag, so that GHC compilation won't fail when some files contain tab
characters.

Test Plan: Additional test case, T9230, was added to cover that change.

Reviewers: austin

Reviewed By: austin

Subscribers: simonmar, ezyang, carter, thomie, mlen

Differential Revision: https://phabricator.haskell.org/D255

GHC Trac Issues: #9230

Conflicts:
	testsuite/driver/testlib.py

This finally exposes also the methods of these 3 classes in the Prelude
in order to allow to define basic class instances w/o needing imports.

This almost completes the primary goal of #9586

NOTE: `fold`, `foldl'`, `foldr'`, and `toList` are not exposed yet,
      as they require upstream fixes for at least `containers` and
      `bytestring`, and are not required for defining basic instances.

Reviewed By: ekmett, austin

Differential Revision: https://phabricator.haskell.org/D236

Summary:
This includes pretty much all the changes needed to make `Applicative`
a superclass of `Monad` finally. There's mostly reshuffling in the
interests of avoid orphans and boot files, but luckily we can resolve
all of them, pretty much. The only catch was that
Alternative/MonadPlus also had to go into Prelude to avoid this.

As a result, we must update the hsc2hs and haddock submodules.
Signed-off-by: Austin Seipp <austin@well-typed.com>

Test Plan: Build things, they might not explode horribly.

Reviewers: hvr, simonmar

Subscribers: simonmar

Differential Revision: https://phabricator.haskell.org/D13

The original proposal text can be found at

  http://www.haskell.org/pipermail/libraries/2014-August/023491.html

The proposal passed with a clear majority, and was additionally
confirmed by the core libraries committee.

*Compatibility Note*

Only code that imports `Data.Word` for the sole purpose of using `Word`
*and* requires to be `-Werror`-clean (due to `-fwarn-unused-imports`)
is affected by this change.

In order to write warning-free forward/backward compatible against `base`,
a variant of the following CPP-based snippet can be used:

  -- Starting with base>4.7.0 or GHC>7.8 Prelude re-exports 'Word'
  -- The following is needed, if 'Word' is the *only* entity needed from Data.Word
  #ifdef MIN_VERSION_base
  # if !MIN_VERSION_base(4,7,1)
  import Data.Word (Word)
  # endif
  -- no cabal_macros.h -- fallback to __GLASGOW_HASKELL__
  #elif __GLASGOW_HASKELL__ < 709
  import Data.Word (Word)
  #endif

This also updates the haddock submodule in order to avoid a compile warning

This was missed when we added binary to the list of boot packages.
But note: the warnings binary are *legitimate* and really should be fixed!
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

GHC should now fully compliant with respect to the Applicative Monad
proposal (including all upstream libraries), and does not need to
suppress this warning anymore.
Signed-off-by: Austin Seipp <austin@well-typed.com>