This is minor stuff triggered by Trac #10103.

* Fix outdated comments on tcView/coreView (we should really combine
  them with a new name, but I'll leave that slightly-disruptive change
  for now)

* Combine tcExpandTyCon_maybe and coreExpandTyCon_maybe (which were identical)
  into expandSynTyCon_maybe

* A few more comment fixups

by giving a sufficient general example to explain what happens when the
rows are not of the same lengths. Thanks to Doug McIlroy for the
suggestoin. Fixes #10128.

This fixes the compilation failure

  libraries\process\System\Process\Internals.hs:36:5:
      Not in scope: `stopDelegateControlC'
      ...

(however, GHC HEAD skipped process-1.2.2 which has that issue)

Summary:
FinderCache is now keyed by a module, ModuleNames in the home package are
turned into Modules using thisPackage in the dynamic flags.  Simplifies some
code!

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

Test Plan: validate

Reviewers: simonpj, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D634

The following operations are only (officially) available starting with
GMP 5.0:

- `mpn_and_n`
- `mpn_andn_n`
- `mpn_ior_n`
- `mpn_xor_n`

In order to properly support GMP 4.x, we simply emulate those operation
in terms of `mpz_*` operations available in GMP 4.x (unless GMP>=5.x
available, obviously) while incurring some overhead. Ideally, GMP 4.x
environments will reach their EOL in the foreseeable future...

This fixes #10003

Reviewed By: austin

Differential Revision: https://phabricator.haskell.org/D675

Summary: New flags:

 -fwarn-unused-top-binds
 -fwarn-unused-local-binds
 -fwarn-unused-pattern-binds

Test Plan: `tests/rename/should_compile/T17` tests

Correct other tests

Reviewers: austin, rwbarton

Reviewed By: austin, rwbarton

Subscribers: rwbarton, carter, thomie

Differential Revision: https://phabricator.haskell.org/D591

GHC Trac Issues: #17

and reference to long-removed note in CallArity.hs

Instead of using double quotes (which are used to link to modules), use
single quotes (that are used to link, among others, to link to types,
which C.E.Exception is).

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

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

Summary:
The current implementation of the Read Integer instance has quadratic
complexity and thus performs badly on large inputs. This patch provides a
rather simple sub-quadratic algorithm. For small inputs, we use the old
algorithm (there is a small penalty for that). The gains for large
inputs can be dramatic: on my system, the time to perform
    read (take 1000000 $ cycle "1234567890") :: Integer
drops from 65 seconds to less than a second.

Note that we already provide an ad-hoc instance for Show Integer, so this
patch essentially does the same thing for Read Integer.

Test Plan: Check that read :: String -> Integer returns correct results for inputs of various sizes.

Reviewers: austin, hvr

Reviewed By: austin, hvr

Subscribers: ekmett, thomie

Differential Revision: https://phabricator.haskell.org/D645

GHC Trac Issues: #10067

See the extensive discussion in #8539

.

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

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

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

There's no reason to have two files, and this is one step towards a
cleaner root directory.

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

This gives a very quick rundown on installation for end-users (HACKING
etc is for developers/possible contributors).

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

Test Plan: deriving/should_run/T10104

Reviewers: austin, jstolarek

Reviewed By: austin, jstolarek

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D672

GHC Trac Issues: #10104

Summary: Currently the linker tries to see if it understands/knows every section in the PE file before it continues. If it encounters a section it doesn't know about it errors out. Every time there's a change in MinGW compiler that adds a new section to the PE file this will break the ghc linker. The new sections don't need to be understood by `ghc` to continue so instead of erroring out the section is just ignored. When running with `-debug` the sections that are ignored will be printed.

Test Plan:
See the file `ghcilinkerbug.zip` in #9907.

 1) unzip file content.
 2) open examplecpp.cabal and change base <4.8 to <4.9.
 3) execute cabal file with cabal repl.

Applying the patch makes `cabal repl` in step 3) work.

Note that the file will fail on a `___mingw_vprintf` not being found. This is because of the `cc-options` specifying `-std=c++0x`, which will also require `libmingwex.a` to be linked in but wasn't specified in the cabal file. To fix this, remove the `cc-options` which defaults to c99.

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D671

GHC Trac Issues: #9907, #7103, #10051, #7056, #8546

Summary:
Given:
  a Makefile with a non-PHONY target called `target`
If:
  after running `make target`, a file exists with the same name as `target`
  (it was either already there, or it was created by running `make target`)
And:
  `target` has no dependencies, such as `clean`, that modify or delete that
  file
Then:
  subsequent invocations of `make target` will not have any effect.

Solution: make `target` PHONY.

BAD:
  ```
  foo:
          ...
          ./foo
  ```

BETTER:
  ```
  foo:
          ...
          ./foo
  .PHONY: foo
  ```

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D670

Summary:
The user package database was already ignored for systems that
`have_subprocess`.

To [wiki:Debugging/InstallingPackagesInplace install] a package inplace:
`cabal install
  --with-compiler=<inplace-ghc>
  --with-package-db=<inplace-package-db>`
  <package>

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D668

Summary:
Remove unused variable that appeared through the fix for ticket #10078

Merge branch 'master' of git://git.haskell.org/ghc

Added comment with bug ID.

Reviewers: adamgundry, gridaphobe, austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D667

GHC Trac Issues: #10078

Summary:
If curses is installed into some non-standard path, we currently have
to say something like the following in mk/build.mk:

  libraries/terminfo_CONFIGURE_OPTS += \
      --configure-option=--with-curses-includes=/somewhere/include \
      --configure-option=--with-curses-libraries=/somewhere/lib

This is because the top-level configure does not accept nor propagate
--with-curses-{includes,libraries} to libraries while it does so for
iconv, gmp and libffi. It would be nice if curses were handled in the
same manner.

Test Plan: Install curses into some non-standard path. Then run the top-level "configure" script with options "--with-curses-includes=/path/to/curses/include" and "--with-curses-libraries=/path/to/curses/lib".

Reviewers: austin

Reviewed By: austin

Subscribers: thomie, PHO

Differential Revision: https://phabricator.haskell.org/D665

GHC Trac Issues: #10096

Summary:
GHC does 2 validation checks for module `Main`:
* does `main` exist
* is `main` exported (#414)

The second check is done in ghc as well as in ghci (and runghc and ghc -e).
The first check however is currently not done in ghci, to prevent "'main' is
not in scope" errors when loading simple scripts. See commit d28ba8c8 for
more information.

This commit tightens the special case for ghci. When the file does not contain
a main function, but does contain an explicit module header (i.e. "module Main
where"), then /do/ raise an error in ghci (and runghc and ghc -e) as well

Test Plan:
module/T7765: a module Main with an explicit module header but without a
main function should be an error for all Ways.

Additionaly: delete test module/mod174. It was added in commit 5a54c38e, but it
is a duplicate of module/T414.

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D649

GHC Trac Issues: #7765

Reviewers: austin, simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D657

These instances were missed when the identity functor was added to
the `base` package (re #9664).

Reviewed By: ekmett

Differential Revision: https://phabricator.haskell.org/D674

David Feuer managed to tickle a corner case in the
code generator. See Note [Scrutinising VoidRep]
in StgCmmExpr.

I rejigged the comments in that area of the code generator
  Note [Dodgy unsafeCoerce 1]
  Note [Dodgy unsafeCoerce 2]
but I can't say I fully understand them, alas.

More subtlety due to functional dependencies.
Note [Redundant constraints in instance decls] in TcErrors.

Fixes Trac #10100.

Summary:
SPJ's solution is to only bring the `TcId` (which includes the type) of a
binder into scope when it had a non-partial type signature.

Take care of this by only storing the `TcId` in `TcSigInfo` of non-partial
type signatures, hence the change to `sig_poly_id :: Maybe TcId`. Only in case
of a `Just` will we bring the `TcId` in scope. We still need to know the name
of the binder, even when it has a partial type signature, so add a `sig_name
:: Name` field. The field `sig_partial :: Bool` is no longer necessary, so
reimplement `isPartialSig` in terms of `sig_poly_id`.

Note that the new test case fails, but not because of a panic, but because the
`Num a` constraint is missing. Adding an extra-constraints wildcard to
`copy`'s signature would fix it.

Test Plan: validate

Reviewers: simonpj, austin

Reviewed By: simonpj

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D646

GHC Trac Issues: #10045

Summary:
* Delete dead code in ghc-pkg (not_yet ready since 2004)
* remove --auto-ghc-libs
Commit 78185538 (2011) mentions:
"Deprecate the ghc-pkg --auto-ghci-libs flag
It was never a universal solution. It only worked with the GNU linker.
It has not been used by Cabal for ages. GHCi can now load .a files so it will
not be needed in future."
"Warning: --auto-ghci-libs is deprecated and will be removed in GHC 7.4"

Reviewers: austin

Reviewed By: austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D666