Summary:
`nlHsFunTy` wasn't parenthesizing its arguments at all,
which led to `-ddump-deriv` producing incorrectly parenthesized
types (since it uses `nlHsFunTy` to construct those types), as
demonstrated in #15307. Fix this by changing `nlHsFunTy` to add
parentheses à la `ppr_ty`: always parenthesizing the argument type
with function precedence, and recursively processing the result type,
adding parentheses for each function type it encounters.

Test Plan: make test TEST=T14578

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #15307

Differential Revision: https://phabricator.haskell.org/D4890

There are several changes here.

* TcInteract has gotten too big, so I moved all the class-instance
  matching out of TcInteract into a new module ClsInst. It parallels
  the FamInst module.

  The main export of ClsInst is matchGlobalInst.
  This now works in TcM not TcS.

* A big reason to make matchGlobalInst work in TcM is that we can
  then use it from TcValidity.checkSimplifiableClassConstraint.
  That extends checkSimplifiableClassConstraint to work uniformly
  for built-in instances, which means that we now get a warning
  if we have givens (Typeable x, KnownNat n); see Trac #15322.

* This change also made me refactor LookupInstResult, in particular
  by adding the InstanceWhat field.  I also changed the name of the
  type to ClsInstResult.

  Then instead of matchGlobalInst reporting a staging error (which is
  inappropriate for the call from TcValidity), we can do so in
  TcInteract.checkInstanceOK.

* In TcValidity, we now check quantified constraints for termination.
  For example, this signature should be rejected:
     f :: (forall a. Eq (m a) => Eq (m a)) => blah
  as discussed in Trac #15316.   The main change here is that
  TcValidity.check_pred_help now uses classifyPredType, and has a
  case for ForAllPred which it didn't before.

  This had knock-on refactoring effects in TcValidity.

See Note [Typeable for Nat and Symbol] in TcInteract,
which I added after discussion on Trac #15322

This reverts commit 6bb0c5db.

See discussion in D4905.

Matthías Páll Gissurarson authored 6 years ago and Ömer Sinan Ağacan committed 6 years ago

This is a one line fix (and a note) that fixes four tickets, #15007,
 #15321 and #15202, #15314

The issue was that errors caused by illegal candidates (according to GHC
stage or being internal names) were leaking to the user, causing
bewildering error messages. If a candidate causes the type checker to
error, it is not a valid hole fit, and should be discarded.

As mentioned in #15321, this can cause a pattern of omissions, which
might be hard to discover. A better approach would be to gather the
error messages, and ask users to report them as GHC bugs. This will be
implemented in a subsequent change.

Reviewers: bgamari, simonpj

Reviewed By: simonpj

Subscribers: simonpj, rwbarton, thomie, carter

GHC Trac Issues: #15007, #15321, #15202, #15314

Differential Revision: https://phabricator.haskell.org/D4909

`extractSubTerms` (which is extracting pointer and non-pointer fields of a
closure) was computing the alignment incorrectly when aligning a 64-bit value
(e.g. a Double) on i386 by aligning it to 64-bits instead of to word size
(32-bits). This is documented in `mkVirtHeapOffsetsWithPadding`:

> Align the start offset (eg, 2-byte value should be 2-byte aligned).
> But not more than to a word.

Fixes #15061

Test Plan:
Validated on both 32-bit and 64-bit. 32-bit fails with various unrelated stat
failures, but no actual test failures.

Reviewers: hvr, bgamari

Reviewed By: bgamari

Subscribers: simonpj, rwbarton, thomie, carter

GHC Trac Issues: #15061

Differential Revision: https://phabricator.haskell.org/D4906

Details are not documented, only the high-level functions

Reviewers: simonpj, hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4911

A GADT declaration surrounded in parens does not det the con_forall
field correctly.

e.g.

data MaybeDefault v where
    TestParens  :: (forall v . (Eq v) => MaybeDefault v)

Closes #15323

It shouldn't be necessary to lock the `MVar` closure on `tryReadMVar`, since it
just reads one field of the structure and doesn't make any modifications. So
let's not.

Reviewers: bgamari, erikd, simonmar, fryguybob, osa1

Reviewed By: osa1

Subscribers: osa1, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4905

Reviewers: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4903

Reviewers: simonmar, bgamari, erikd

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4893

Comments only: [ci skip]

Remove unsafeCoerce introduced by a54c94f0

Reviewers: simonmar, bgamari

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4901

Reviewers: simonmar, bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4892

...provoked by Trac #15308

The level numbers we were getting simply didn't obey the
invariant (ImplicInv) in TcType
   Note [TcLevel and untouchable type variables]

That leads to chaos. Easy to fix.  I improved the documentation.

I also added an assertion in TcSimplify that checks that
level numbers go up by 1 as we dive inside implications, so
that we catch the problem at source rather than than through
its obscure consequences.

That in turn showed up that TcRules was also generating
constraints that didn't obey (ImplicInv), so I fixed that too.
I have no idea what consequences were lurking behing that
bug, but anyway now it's fixed.  Hooray.

Make sure the original annotations are still accessible for a promoted
type.

Closes #15303

I wondered if some transformations (ticks) might be "innocuous",
in the sense that they do not unlock a later transformation that
does not occur in the same pass.  If so, we could refrain from
bumping the overall tick-count for such innocuous transformations,
and perhaps terminate the simplifier one pass earlier.

BUt alas I found that virtually nothing was innocuous!  This
commit just adds a Note to record what I learned, in case
anyone wants to try again.

... plus, reorder equations in toIfaceVar to improve
legibility.  No change in behaviour.

See Trac #15205

The refactoring here is driven by the ghastly mess described in
comment:24 of Trac #1520.  The overall goal is to simplify the
kind-checking of typev-variable binders, and in particular to narrow
the use of the "in-scope tyvar binder" stuff,
which is needed only for associated types: see the new
Note [Kind-checking tyvar binders for associated types] in TcHsType.

Now

* The "in-scope tyvar binder" stuff is done only in
     - kcLHsQTyVars, which is used for the LHsQTyVars of a
       data/newtype, or type family declaration.

     - tcFamTyPats, which is used for associated family instances;
       it now calls tcImplicitQTKBndrs, which in turn usese
       newFlexiKindedQTyVar

* tcExpicitTKBndrs (which is used only for function signatures,
  data con signatures, pattern synonym signatures, and expression
  type signatures) now does not go via the "in-scope tyvar binder"
  stuff at all.

While I'm still not happy with all this code, the code is generally
simpler, and I think this is a useful step forward. It does cure
the problem too.

(It's hard to trigger the problem in vanilla Haskell code, because
the renamer would normally use different names for nested binders,
so I can't offer a test.)

As Trac #15289 showed, we were carrying on after a type error
in a pattern synonym, and then crashing.  This patch improves
error handling for pattern synonyms.

I also moved a bit of code from TcBinds into TcPatSyn, which
helpfully narrows the API.

Test Plan: "ghc -Wamp XXX.hs"  should give "unrecognised warning flag"

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #11477

Differential Revision: https://phabricator.haskell.org/D4785

protect mmaped addresses from writes after being initially manipulated

Test Plan: ./validate

Reviewers: bgamari, erikd, simonmar

Reviewed By: bgamari

Subscribers: angerman, carlostome, rwbarton, thomie, carter

GHC Trac Issues: #14069

Differential Revision: https://phabricator.haskell.org/D4817

Ben Gamari authored 6 years ago and Ben Gamari committed 6 years ago

Currently we belch some output to stderr but fail to abort, resulting in
a busy loop. Fixes #15292.

Test Plan:
 * Validate
 * try running program under environment without timerfd capabilities;
ensure we don't busy-loop

Reviewers: simonmar, erikd

Reviewed By: simonmar

Subscribers: rwbarton, thomie, carter

GHC Trac Issues: #15929

Differential Revision: https://phabricator.haskell.org/D4875

Previously, the `make clean` (as well as `make dist-clean`) doesn't work
for ghc-heap and libiserv, due to these two libraries are not presented
in the "packages" file.

Test Plan: [skip ci]

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4878

We just update the docs to reflect the state of affairs.

opt-cmm is run by the NCG backend so not always run.
ddump-cmm-verbose only dumps passes of the cmm
pipeline so it's not included there. [skip-ci]

Test Plan: doc change

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4879