GitLab

I had a conversation with Richard about TyBinders
and VisibilityFlags.  This patch adds a lot of comments
to explain what is going on.  I feel much more secure now.

Richard please check.

In particular, this allows correct tracking of specified/invisible
for variables in Haskell98 data constructors and in pattern synonyms.
GADT-syntax constructors are harder, and are left until #11721.

This was all inspired by Simon's comments to my fix for #11512,
which this subsumes.

Test case: ghci/scripts/TypeAppData

[skip ci]  (The test case fails because of an unrelated problem
fixed in the next commit.)

See Note [TYPE] in TysPrim. There are still some outstanding
pieces in #11471 though, so this doesn't actually nail the bug.

This commit also contains a few performance improvements:

* Short-cut equality checking of nullary type syns

* Compare types before kinds in eqType

* INLINE coreViewOneStarKind

* Store tycon binders separately from kinds.

This resulted in a ~10% performance improvement in compiling
the Cabal package. No change in functionality other than
performance. (This affects the interface file format, though.)

This commit updates the haddock submodule.

This addresses point (2) from #11513.

This is the renaming that @simonpj requested:
```
· zipOpenTCvSubst  -> zipTvSubst   (It only deals with tyvars)

· zipOpenTCvSubstCoVars -> zipCvSubst   (it only deals with
covars)

· zipOpenTCvSubstBinders ->  zipTyBinderSubst  (it only deals
with TyBinders, not covars)
```
plus the `mk` variant.

Test Plan: ./validate

Reviewers: simonpj, goldfire, austin, bgamari

Subscribers: thomie, simonpj

Differential Revision: https://phabricator.haskell.org/D1853

GHC Trac Issues: #11371

Summary:
In the past the canonical way for constructing an SDoc string literal was the
composition `ptext . sLit`.  But for some time now we have function `text` that
does the same.  Plus it has some rules that optimize its runtime behaviour.
This patch takes all uses of `ptext . sLit` in the compiler and replaces them
with calls to `text`.  The main benefits of this patch are clener (shorter) code
and less dependencies between module, because many modules now do not need to
import `FastString`.  I don't expect any performance benefits - we mostly use
SDocs to report errors and it seems there is little to be gained here.

Test Plan: ./validate

Reviewers: bgamari, austin, goldfire, hvr, alanz

Subscribers: goldfire, thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D1784

This re-working of the typechecker algorithm is based on
the paper "Visible type application", by Richard Eisenberg,
Stephanie Weirich, and Hamidhasan Ahmed, to be published at
ESOP'16.

This patch introduces -XTypeApplications, which allows users
to say, for example `id @Int`, which has type `Int -> Int`. See
the changes to the user manual for details.

This patch addresses tickets #10619, #5296, #10589.

This implements the ideas originally put forward in
"System FC with Explicit Kind Equality" (ICFP'13).

There are several noteworthy changes with this patch:
 * We now have casts in types. These change the kind
   of a type. See new constructor `CastTy`.

 * All types and all constructors can be promoted.
   This includes GADT constructors. GADT pattern matches
   take place in type family equations. In Core,
   types can now be applied to coercions via the
   `CoercionTy` constructor.

 * Coercions can now be heterogeneous, relating types
   of different kinds. A coercion proving `t1 :: k1 ~ t2 :: k2`
   proves both that `t1` and `t2` are the same and also that
   `k1` and `k2` are the same.

 * The `Coercion` type has been significantly enhanced.
   The documentation in `docs/core-spec/core-spec.pdf` reflects
   the new reality.

 * The type of `*` is now `*`. No more `BOX`.

 * Users can write explicit kind variables in their code,
   anywhere they can write type variables. For backward compatibility,
   automatic inference of kind-variable binding is still permitted.

 * The new extension `TypeInType` turns on the new user-facing
   features.

 * Type families and synonyms are now promoted to kinds. This causes
   trouble with parsing `*`, leading to the somewhat awkward new
   `HsAppsTy` constructor for `HsType`. This is dispatched with in
   the renamer, where the kind `*` can be told apart from a
   type-level multiplication operator. Without `-XTypeInType` the
   old behavior persists. With `-XTypeInType`, you need to import
   `Data.Kind` to get `*`, also known as `Type`.

 * The kind-checking algorithms in TcHsType have been significantly
   rewritten to allow for enhanced kinds.

 * The new features are still quite experimental and may be in flux.

 * TODO: Several open tickets: #11195, #11196, #11197, #11198, #11203.

 * TODO: Update user manual.

Tickets addressed: #9017, #9173, #7961, #10524, #8566, #11142.
Updates Haddock submodule.

This is the second attempt at merging D757.

This patch implements the idea floated in Trac #9858, namely that we
should generate type-representation information at the data type
declaration site, rather than when solving a Typeable constraint.

However, this turned out quite a bit harder than I expected. I still
think it's the right thing to do, and it's done now, but it was quite
a struggle.

See particularly

 * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
 * Note [The overall promotion story] in DataCon (clarifies existing
stuff)

The most painful bit was that to generate Typeable instances (ie
TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
etc:

 * We need to have enough data types around to *define* a TyCon
 * Many of these types are wired-in

Also, to minimise the code generated for each data type, I wanted to
generate pure data, not CAFs with unpackCString# stuff floating about.

Performance
~~~~~~~~~~~
Three perf/compiler tests start to allocate quite a bit more. This isn't
surprising, because they all allocate zillions of data types, with
practically no other code, esp. T1969

 * T1969:    GHC allocates 19% more
 * T4801:    GHC allocates 13% more
 * T5321FD:  GHC allocates 13% more
 * T9675:    GHC allocates 11% more
 * T783:     GHC allocates 11% more
 * T5642:    GHC allocates 10% more

I'm treating this as acceptable. The payoff comes in Typeable-heavy
code.

Remaining to do
~~~~~~~~~~~~~~~

 * I think that "TyCon" and "Module" are over-generic names to use for
   the runtime type representations used in GHC.Typeable. Better might
be
   "TrTyCon" and "TrModule". But I have not yet done this

 * Add more info the the "TyCon" e.g. source location where it was
   defined

 * Use the new "Module" type to help with Trac Trac #10068

 * It would be possible to generate TyConRepName (ie Typeable
   instances) selectively rather than all the time. We'd need to persist
   the information in interface files. Lacking a motivating reason I
have
   not done this, but it would not be difficult.

Refactoring
~~~~~~~~~~~
As is so often the case, I ended up refactoring more than I intended.
In particular

 * In TyCon, a type *family* (whether type or data) is repesented by a
   FamilyTyCon
     * a algebraic data type (including data/newtype instances) is
       represented by AlgTyCon This wasn't true before; a data family
       was represented as an AlgTyCon. There are some corresponding
       changes in IfaceSyn.

     * Also get rid of the (unhelpfully named) tyConParent.

 * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
   optionally promoted; and use it elsewhere in GHC.

 * Cleanup handling of knownKeyNames

 * Each TyCon, including promoted TyCons, contains its TyConRepName, if
   it has one. This is, in effect, the name of its Typeable instance.

Updates haddock submodule

Test Plan: Let Harbormaster validate

Reviewers: austin, hvr, goldfire

Subscribers: goldfire, thomie

Differential Revision: https://phabricator.haskell.org/D1404

GHC Trac Issues: #9858

This reverts commit bef2f03e.

This merge was botched

Also reverts haddock submodule.

This patch implements the idea floated in Trac #9858, namely that we
should generate type-representation information at the data type
declaration site, rather than when solving a Typeable constraint.

However, this turned out quite a bit harder than I expected. I still
think it's the right thing to do, and it's done now, but it was quite
a struggle.

See particularly

 * Note [Grand plan for Typeable] in TcTypeable (which is a new module)
 * Note [The overall promotion story] in DataCon (clarifies existing stuff)

The most painful bit was that to generate Typeable instances (ie
TyConRepName bindings) for every TyCon is tricky for types in ghc-prim
etc:

 * We need to have enough data types around to *define* a TyCon
 * Many of these types are wired-in

Also, to minimise the code generated for each data type, I wanted to
generate pure data, not CAFs with unpackCString# stuff floating about.

Performance
~~~~~~~~~~~
Three perf/compiler tests start to allocate quite a bit more. This isn't
surprising, because they all allocate zillions of data types, with
practically no other code, esp. T1969

 * T3294:   GHC allocates 110% more (filed #11030 to track this)
 * T1969:   GHC allocates 30% more
 * T4801:   GHC allocates 14% more
 * T5321FD: GHC allocates 13% more
 * T783:    GHC allocates 12% more
 * T9675:   GHC allocates 12% more
 * T5642:   GHC allocates 10% more
 * T9961:   GHC allocates 6% more

 * T9203:   Program allocates 54% less

I'm treating this as acceptable. The payoff comes in Typeable-heavy
code.

Remaining to do
~~~~~~~~~~~~~~~

 * I think that "TyCon" and "Module" are over-generic names to use for
   the runtime type representations used in GHC.Typeable. Better might be
   "TrTyCon" and "TrModule". But I have not yet done this

 * Add more info the the "TyCon" e.g. source location where it was
   defined

 * Use the new "Module" type to help with Trac Trac #10068

 * It would be possible to generate TyConRepName (ie Typeable
   instances) selectively rather than all the time. We'd need to persist
   the information in interface files. Lacking a motivating reason I have
   not done this, but it would not be difficult.

Refactoring
~~~~~~~~~~~
As is so often the case, I ended up refactoring more than I intended.
In particular

 * In TyCon, a type *family* (whether type or data) is repesented by a
   FamilyTyCon
     * a algebraic data type (including data/newtype instances) is
       represented by AlgTyCon This wasn't true before; a data family
       was represented as an AlgTyCon. There are some corresponding
       changes in IfaceSyn.

     * Also get rid of the (unhelpfully named) tyConParent.

 * In TyCon define 'Promoted', isomorphic to Maybe, used when things are
   optionally promoted; and use it elsewhere in GHC.

 * Cleanup handling of knownKeyNames

 * Each TyCon, including promoted TyCons, contains its TyConRepName, if
   it has one. This is, in effect, the name of its Typeable instance.

Requires update of the haddock submodule.

Differential Revision: https://phabricator.haskell.org/D757

This implements DuplicateRecordFields, the first part of the
OverloadedRecordFields extension, as described at
https://ghc.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/DuplicateRecordFields

This includes fairly wide-ranging changes in order to allow multiple
records within the same module to use the same field names.  Note that
it does *not* allow record selector functions to be used if they are
ambiguous, and it does not have any form of type-based disambiguation
for selectors (but it does for updates). Subsequent parts will make
overloading selectors possible using orthogonal extensions, as
described on the wiki pages.  This part touches quite a lot of the
codebase, and requires changes to several GHC API datatypes in order
to distinguish between field labels (which may be overloaded) and
selector function names (which are always unique).

The Haddock submodule has been adapted to compile with the GHC API
changes, but it will need further work to properly support modules
that use the DuplicateRecordFields extension.

Test Plan: New tests added in testsuite/tests/overloadedrecflds; these
will be extended once the other parts are implemented.

Reviewers: goldfire, bgamari, simonpj, austin

Subscribers: sjcjoosten, haggholm, mpickering, bgamari, tibbe, thomie,
goldfire

Differential Revision: https://phabricator.haskell.org/D761

Comes with Haddock submodule update.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Updates haddock submodule.

Reviewers: tibbe, goldfire, simonpj, austin, bgamari

Reviewed By: simonpj, bgamari

Subscribers: goldfire, thomie, mpickering

Differential Revision: https://phabricator.haskell.org/D1069

This implements the `StrictData` language extension, which lets the
programmer default to strict data fields in datatype declarations on a
per-module basis.

Specification and motivation can be found at
https://ghc.haskell.org/trac/ghc/wiki/StrictPragma

This includes a tricky parser change due to conflicts regarding `~` in
the type level syntax: all ~'s are parsed as strictness annotations (see
`strict_mark` in Parser.y) and then turned into equality constraints at
the appropriate places using `RdrHsSyn.splitTilde`.

Updates haddock submodule.

Test Plan: Validate through Harbormaster.

Reviewers: goldfire, austin, hvr, simonpj, tibbe, bgamari

Reviewed By: simonpj, tibbe, bgamari

Subscribers: lelf, simonpj, alanz, goldfire, thomie, bgamari, mpickering

Differential Revision: https://phabricator.haskell.org/D1033

GHC Trac Issues: #8347

In dataConCannotMatch we were using a GADT data con without
properly instantiating the existential type variables.
The fix is easy, and the code is tighter.

The other one is MkId.hs.

Make tuple constraints be handled by a perfectly ordinary
type class, with the component constraints being the
superclasses:
    class (c1, c2) => (c2, c2)

This change was provoked by

  #10359  inability to re-use a given tuple
          constraint as a whole

  #9858   confusion between term tuples
          and constraint tuples

but it's generally a very nice simplification. We get rid of
 -  In Type, the TuplePred constructor of PredTree,
    and all the code that dealt with TuplePreds
 -  In TcEvidence, the constructors EvTupleMk, EvTupleSel

See Note [How tuples work] in TysWiredIn.

Of course, nothing is ever entirely simple. This one
proved quite fiddly.

- I did quite a bit of renaming, which makes this patch
  touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.

- I made constraint tuples known-key rather than wired-in.
  This is different to boxed/unboxed tuples, but it proved
  awkward to have all the superclass selectors wired-in.
  Easier just to use the standard mechanims.

- While I was fiddling with known-key names, I split the TH Name
  definitions out of DsMeta into a new module THNames.  That meant
  that the known-key names can all be gathered in PrelInfo, without
  causing module loops.

- I found that the parser was parsing an import item like
      T( .. )
  as a *data constructor* T, and then using setRdrNameSpace to
  fix it.  Stupid!  So I changed the parser to parse a *type
  constructor* T, which means less use of setRdrNameSpace.

  I also improved setRdrNameSpace to behave better on Exact Names.
  Largely on priciple; I don't think it matters a lot.

- When compiling a data type declaration for a wired-in thing like
  tuples (,), or lists, we don't really need to look at the
  declaration.  We have the wired-in thing!  And not doing so avoids
  having to line up the uniques for data constructor workers etc.
  See Note [Declarations for wired-in things]

- I found that FunDeps.oclose wasn't taking superclasses into
  account; easily fixed.

- Some error message refactoring for invalid constraints in TcValidity

- Haddock needs to absorb the change too; so there is a submodule update

This reverts multiple commits from Simon:

  - 04a484ea Test Trac #10359
  - a9ccd37a Test Trac #10403
  - c0aae6f6 Test Trac #10248
  - eb6ca851 Make the "matchable-given" check happen first
  - ca173aa3 Add a case to checkValidTyCon
  - 51cbad15 Update haddock submodule
  - 6e1174da Separate transCloVarSet from fixVarSet
  - a8493e03 Fix imports in HscMain (stage2)
  - a154944b Two wibbles to fix the build
  - 5910a1bc Change in capitalisation of error msg
  - 130e93aa Refactor tuple constraints
  - 8da785d5 Delete commented-out line

These break the build by causing Haddock to fail mysteriously when
trying to examine GHC.Prim it seems.

Make tuple constraints be handled by a perfectly ordinary
type class, with the component constraints being the
superclasses:
    class (c1, c2) => (c2, c2)

This change was provoked by

  #10359  inability to re-use a given tuple
          constraint as a whole

  #9858   confusion between term tuples
          and constraint tuples

but it's generally a very nice simplification. We get rid of
 -  In Type, the TuplePred constructor of PredTree,
    and all the code that dealt with TuplePreds
 -  In TcEvidence, the constructors EvTupleMk, EvTupleSel

See Note [How tuples work] in TysWiredIn.

Of course, nothing is ever entirely simple. This one
proved quite fiddly.

- I did quite a bit of renaming, which makes this patch
  touch a lot of modules. In partiuclar tupleCon -> tupleDataCon.

- I made constraint tuples known-key rather than wired-in.
  This is different to boxed/unboxed tuples, but it proved
  awkward to have all the superclass selectors wired-in.
  Easier just to use the standard mechanims.

- While I was fiddling with known-key names, I split the TH Name
  definitions out of DsMeta into a new module THNames.  That meant
  that the known-key names can all be gathered in PrelInfo, without
  causing module loops.

- I found that the parser was parsing an import item like
      T( .. )
  as a *data constructor* T, and then using setRdrNameSpace to
  fix it.  Stupid!  So I changed the parser to parse a *type
  constructor* T, which means less use of setRdrNameSpace.

  I also improved setRdrNameSpace to behave better on Exact Names.
  Largely on priciple; I don't think it matters a lot.

- When compiling a data type declaration for a wired-in thing like
  tuples (,), or lists, we don't really need to look at the
  declaration.  We have the wired-in thing!  And not doing so avoids
  having to line up the uniques for data constructor workers etc.
  See Note [Declarations for wired-in things]

- I found that FunDeps.oclose wasn't taking superclasses into
  account; easily fixed.

- Some error message refactoring for invalid constraints in TcValidity

Beofre this commit we never unboxed GADT, even if they
are perfectly civilised products.

This patch liberalises unboxing slightly.
See Note [Product types] in TyCon.

Still to come
 - for strictness, we could maybe deal with existentials too
 - todo: unboxing constructor arguments

Summary: It looks like during .lhs -> .hs switch the comments were not updated. So doing exactly that.

Reviewers: austin, jstolarek, hvr, goldfire

Reviewed By: austin, jstolarek

Subscribers: thomie, goldfire

Differential Revision: https://phabricator.haskell.org/D621

GHC Trac Issues: #9986

Summary:
Add a reference note to each AnnKeywordId haddock comment so GHC
developers will have an idea why they are there.

Add a new test to ghc-api/annotations to serve as a template for other
GHC developers when they need to update the parser. It provides output
which checks that each SrcSpan that an annotation is attached to
actually appears in the `ParsedSource`, and lists the individual
annotations. The idea is that a developer writes a version of this
which parses a sample file using whatever syntax is changed in
Parser.y, and can then check that all the annotations come through.

Depends on D538

Test Plan: ./validate

Reviewers: simonpj, hvr, austin

Reviewed By: austin

Subscribers: thomie, jstolarek

Differential Revision: https://phabricator.haskell.org/D620

Summary:
HsTyLit now has SourceText

Update documentation of HsSyn to reflect which annotations are attached to which element.

Ensure that the parser always keeps HsSCC and HsTickPragma values, to
be ignored in the desugar phase if not needed

Bringing in SourceText for pragmas

Add Location in NPlusKPat

Add Location in FunDep

Make RecCon payload Located

Explicitly add AnnVal to RdrName where it is compound

Add Location in IPBind

Add Location to name in IEThingAbs

Add Maybe (Located id,Bool) to Match to track fun_id,infix
  This includes converting Match into a record and adding a note about why
  the fun_id needs to be replicated in the Match.

Add Location in KindedTyVar

Sort out semi-colons for parsing

  - import statements
  - stmts
  - decls
  - decls_cls
  - decls_inst

This updates the haddock submodule.

Test Plan: ./validate

Reviewers: hvr, austin, goldfire, simonpj

Reviewed By: simonpj

Subscribers: thomie, carter

Differential Revision: https://phabricator.haskell.org/D538

In particular about the dcSrcBangs field of an imported DataCon

This fixes Trac #9969, a new crash in T7562 that I somehow missed when
fiddling with HsBang

Provoked by questions from Johan

 - Improve comments, fix misleading stuff
 - Add commented synonyms for HsSrcBang, HsImplBang, and use them throughout
 - Rename HsUserBang to HsSrcBang
 - Rename dataConStrictMarks to dataConSrcBangs
          dataConRepBangs    to dataConImplBangs

This renaming affects Haddock in a trivial way, hence submodule update

Summary:
This is a rewrite of the algorithm to solve for Coercible "instances".

A preliminary form of these ideas is at
https://ghc.haskell.org/trac/ghc/wiki/Design/NewCoercibleSolver

The basic idea here is that the `EqPred` constructor of `PredTree`
now is parameterised by a new type `EqRel` (where
`data EqRel = NomEq | ReprEq`). Thus, every equality constraint can
now talk about nominal equality (the usual case) or representational
equality (the `Coercible` case).

This is a change from the previous
behavior where `Coercible` was just considered a regular class with
a special case in `matchClassInst`.

Because of this change, representational equalities are now
canonicalized just like nominal ones, allowing more equalities
to be solved -- in particular, the case at the top of #9117.

A knock-on effect is that the flattener must be aware of the
choice of equality relation, because the inert set now stores
both representational inert equalities alongside the nominal
inert equalities. Of course, we can use representational equalities
to rewrite only within another representational equality --
thus the parameterization of the flattener.

A nice side effect of this change is that I've introduced a new
type `CtFlavour`, which tracks G vs. W vs. D, removing some ugliness
in the flattener.

This commit includes some refactoring as discussed on D546.
It also removes the ability of Deriveds to rewrite Deriveds.

This fixes bugs #9117 and #8984.

Reviewers: simonpj, austin, nomeata

Subscribers: carter, thomie

Differential Revision: https://phabricator.haskell.org/D546

GHC Trac Issues: #9117, #8984

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

Summary:
The final design and discussion is captured at
https://ghc.haskell.org/trac/ghc/wiki/GhcAstAnnotations

This is a proof of concept implementation of a completely
separate annotation structure, populated in the parser,and tied to the
AST by means of a virtual "node-key" comprising the surrounding
SrcSpan and a value derived from the specific constructor used for the
node.

The key parts of the design are the following.

== The Annotations ==

In `hsSyn/ApiAnnotation.hs`

```lang=haskell
type ApiAnns = (Map.Map ApiAnnKey SrcSpan, Map.Map SrcSpan [Located Token])

type ApiAnnKey = (SrcSpan,AnnKeywordId)

-- ---------------------------------------------------------------------

-- | Retrieve an annotation based on the @SrcSpan@ of the annotated AST
-- element, and the known type of the annotation.
getAnnotation :: ApiAnns -> SrcSpan -> AnnKeywordId -> Maybe SrcSpan
getAnnotation (anns,_) span ann = Map.lookup (span,ann) anns

-- |Retrieve the comments allocated to the current @SrcSpan@
getAnnotationComments :: ApiAnns -> SrcSpan -> [Located Token]
getAnnotationComments (_,anns) span =
  case Map.lookup span anns of
    Just cs -> cs
    Nothing -> []

-- | Note: in general the names of these are taken from the
-- corresponding token, unless otherwise noted
data AnnKeywordId
         = AnnAs
         | AnnBang
         | AnnClass
         | AnnClose -- ^ } or ] or ) or #) etc
         | AnnComma
         | AnnDarrow
         | AnnData
         | AnnDcolon
         ....
```

== Capturing in the lexer/parser ==

The annotations are captured in the lexer / parser by extending PState to include a field

In `parser/Lexer.x`

```lang=haskell
data PState = PState {
        ....
        annotations :: [(ApiAnnKey,SrcSpan)]
        -- Annotations giving the locations of 'noise' tokens in the
        -- source, so that users of the GHC API can do source to
        -- source conversions.
     }
```

The lexer exposes a helper function to add an annotation

```lang=haskell
addAnnotation :: SrcSpan -> Ann -> SrcSpan -> P ()
addAnnotation l a v = P $ \s -> POk s {
  annotations = ((AK l a), v) : annotations s
  } ()

```

The parser also has some helper functions of the form

```lang=haskell
type MaybeAnn = Maybe (SrcSpan -> P ())

gl = getLoc
gj x = Just (gl x)

ams :: Located a -> [MaybeAnn] -> P (Located a)
ams a@(L l _) bs = (mapM_ (\a -> a l) $ catMaybes bs) >> return a
```

This allows annotations to be captured in the parser by means of

```
ctypedoc :: { LHsType RdrName }
        : 'forall' tv_bndrs '.' ctypedoc {% hintExplicitForall (getLoc $1) >>
                                            ams (LL $ mkExplicitHsForAllTy $2 (noLoc []) $4)
                                                [mj AnnForall $1,mj AnnDot $3] }
        | context '=>' ctypedoc         {% ams (LL $ mkQualifiedHsForAllTy   $1 $3)
                                               [mj AnnDarrow $2] }
        | ipvar '::' type               {% ams (LL (HsIParamTy (unLoc $1) $3))
                                               [mj AnnDcolon $2] }
        | typedoc                       { $1 }
```

== Parse result ==

```lang-haskell
data HsParsedModule = HsParsedModule {
    hpm_module    :: Located (HsModule RdrName),
    hpm_src_files :: [FilePath],
       -- ^ extra source files (e.g. from #includes).  The lexer collects
       -- these from '# <file> <line>' pragmas, which the C preprocessor
       -- leaves behind.  These files and their timestamps are stored in
       -- the .hi file, so that we can force recompilation if any of
       -- them change (#3589)
    hpm_annotations :: ApiAnns
  }

-- | The result of successful parsing.
data ParsedModule =
  ParsedModule { pm_mod_summary   :: ModSummary
               , pm_parsed_source :: ParsedSource
               , pm_extra_src_files :: [FilePath]
               , pm_annotations :: ApiAnns }
```

This diff depends on D426

Test Plan: sh ./validate

Reviewers: austin, simonpj, Mikolaj

Reviewed By: simonpj, Mikolaj

Subscribers: Mikolaj, goldfire, thomie, carter

Differential Revision: https://phabricator.haskell.org/D438

GHC Trac Issues: #9628

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

Summary:
Previously, both Cabal and GHC defined the type PackageId, and we expected
them to be roughly equivalent (but represented differently).  This refactoring
separates these two notions.

A package ID is a user-visible identifier; it's the thing you write in a
Cabal file, e.g. containers-0.9.  The components of this ID are semantically
meaningful, and decompose into a package name and a package vrsion.

A package key is an opaque identifier used by GHC to generate linking symbols.
Presently, it just consists of a package name and a package version, but
pursuant to #9265 we are planning to extend it to record other information.
Within a single executable, it uniquely identifies a package.  It is *not* an
InstalledPackageId, as the choice of a package key affects the ABI of a package
(whereas an InstalledPackageId is computed after compilation.)  Cabal computes
a package key for the package and passes it to GHC using -package-name (now
*extremely* misnamed).

As an added bonus, we don't have to worry about shadowing anymore.

As a follow on, we should introduce -current-package-key having the same role as
-package-name, and deprecate the old flag.  This commit is just renaming.

The haddock submodule needed to be updated.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, simonmar, hvr, austin

Subscribers: simonmar, relrod, carter

Differential Revision: https://phabricator.haskell.org/D79

Conflicts:
	compiler/main/HscTypes.lhs
	compiler/main/Packages.lhs
	utils/haddock

In some cases, the layout of the LANGUAGE/OPTIONS_GHC lines has been
reorganized, while following the convention, to

- place `{-# LANGUAGE #-}` pragmas at the top of the source file, before
  any `{-# OPTIONS_GHC #-}`-lines.

- Moreover, if the list of language extensions fit into a single
  `{-# LANGUAGE ... -#}`-line (shorter than 80 characters), keep it on one
  line. Otherwise split into `{-# LANGUAGE ... -#}`-lines for each
  individual language extension. In both cases, try to keep the
  enumeration alphabetically ordered.
  (The latter layout is preferable as it's more diff-friendly)

While at it, this also replaces obsolete `{-# OPTIONS ... #-}` pragma
occurences by `{-# OPTIONS_GHC ... #-}` pragmas.