Also, reword :print description.
Signed-off-by: Austin Seipp <austin@well-typed.com>

This also updates the `transformers` submodule to the just
released `transformers-0.4.2.0` package version.

See #9664 for more details

Reviewed By: austin, ekmett

Differential Revision: https://phabricator.haskell.org/D313

Control.Applicative previously imported `(.)` and `id` from `Control.Arrow`,
but then only applied them to functions.

Reviewed By: ekmett, hvr

Differential Revision: https://phabricator.haskell.org/D462

This is a follow-up commit to df3b1d43

This requires ensuring the continuations have arguments by adding a dummy
Void# argument when needed. This is so that matching on a pattern synonym
is lazy even when the result is unboxed, e.g.

    pattern P = ()
    f P = 0#

In this case, without dummy arguments, the generated matcher's type would be

   $mP :: forall (r :: ?). () -> r -> r -> r

which is called in `f` at type `() -> Int# -> Int# -> Int#`,
so it would be strict, in particular, in the failure continuation
of `patError`.

We work around this by making sure both continuations have arguments:

  $mP :: forall (r :: ?). () -> (Void# -> r) -> (Void# -> r) -> r

Of course, if `P` (and thus, the success continuation) has any arguments,
we are only adding the extra dummy argument to the failure continuation.

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

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

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

This makes nub and nubBy behave as specified in the Haskell 98 Report.

This reverts 0ad9def5, and
fixes #3280, #7913 and #2528 (properly).

Before this change, the output of `T2528` was (4x wrong):
```
[A,B]
[1,2]
False
False
```

Reviewed By: dfeuer, ekmett, austin, hvr

Differential Revision: https://phabricator.haskell.org/D238

This commit mostly converts literate comments into ordinary
Haskell comments or sometimes even Haddock comments, while also
removing literate comments in a few cases where they don't make
much sense anymore.

Moreover, in a few cases trailing whitespaces were removed as well.

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D456

This should have gone in with the update in testlib.py to split
off stat test failures into a separate category in the summary.

Reviewers: austin

Reviewed By: austin

Subscribers: thomie, carter

Differential Revision: https://phabricator.haskell.org/D451

Summary: There was a comment about that. Seems like a better behaviour.

Reviewers: austin

Reviewed By: austin

Subscribers: thomie, carter, simonmar

Differential Revision: https://phabricator.haskell.org/D419

Summary: Some of the links in user's guide were broken, I've found the files they used to link and updated urls.

Reviewers: austin

Reviewed By: austin

Subscribers: thomie, carter, simonmar

Differential Revision: https://phabricator.haskell.org/D418

Summary:
The last three '#define ...' macros were removed from Parser.y.pp and this file was renamed to Parser.y.
This basically got rid of a CPP step in the build.

Also converted two modules in compiler/parser/ from .lhs to .hs.

Test Plan: Does it build? Yes, I performed a full build here and things are looking good.

Reviewers: austin

Reviewed By: austin

Subscribers: adamse, thomie, carter, simonmar

Differential Revision: https://phabricator.haskell.org/D411

Summary:
My previous attempt to fix the new coercion bug introduced by my fix actually
just reverted back to the *old* bug. This time it should properly handle all
three size scenarios.
Signed-off-by: Merijn Verstraaten <merijn@inconsistent.nl>

Test Plan: validate

Reviewers: dfeuer, austin, hvr

Reviewed By: austin, hvr

Subscribers: thomie, carter, simonmar

Differential Revision: https://phabricator.haskell.org/D407

GHC Trac Issues: #8089

Signed-off-by: Austin Seipp <austin@well-typed.com>

It's prettier that way, and there's less risk of anything
going sideways.

Reviewed By: hvr, simonpj

Differential Revision: https://phabricator.haskell.org/D450

Generally clean up things relating to Applicative and Monad in `GHC.Base`
and `Control.Applicative` to make `Applicative` feel like a bit more of a
first-class citizen rather than just playing second fiddle to `Monad`. Use
`coerce` and GND to improve performance and clarity.

Change the default definition of `(*>)` to use `(<$)`, in case the
`Functor` instance optimizes that.

Moreover, some manually written instances are made into compiler-derived
instances.

Finally, this also adds a few AMP-related laws to the `Applicative` docstring.

NOTE: These changes result in a 13% decrease in allocation for T9020

Reviewed By: ekmett, hvr

Differential Revision: https://phabricator.haskell.org/D432

-XIncoherentInstances turned on.

Haskell.

The main description is in Note [Preventing recursive dictionaries]
in TcRnTypes, which applies only to Coercible dictionaries.

But it was a bit of a mess:
 - It wasn't applied consistently
 - It was being applied to non-Coercible dictionaries in some places

This patch tidies it up.

This hack will largely go away when Richard starts treating Coercible
constraints more like equalities than like dictionaries.

See Note [Propagate solved dictionaries] in TcSMonad.  This
can signficantly reduce the number of solver steps.

See Note [Lazy flattening] in TcFlatten.

Lazy flattening was an apparently good idea which actually made
the type inference engine go a LOTS slower in T3064.  So I switched
it off again.

A little refactoring

This improves error messages when there is a type error,
fixing Trac #9774

Add doctest examples for every data type and function in `Data.Either`

Differential Revision: https://phabricator.haskell.org/D443