[commit: ghc] wip/ppc-reg-alloc: Treat kind/type variables identically, demolish FKTV (5bc195b)
git at git.haskell.org
git at git.haskell.org
Thu Feb 28 02:14:42 UTC 2019
Repository : ssh://git@git.haskell.org/ghc
On branch : wip/ppc-reg-alloc
Link : http://ghc.haskell.org/trac/ghc/changeset/5bc195b1fe788e9a900a15fbe473967850517c3e/ghc
>---------------------------------------------------------------
commit 5bc195b1fe788e9a900a15fbe473967850517c3e
Author: Vladislav Zavialov <vlad.z.4096 at gmail.com>
Date: Wed Feb 13 17:15:49 2019 +0300
Treat kind/type variables identically, demolish FKTV
Implements GHC Proposal #24: .../ghc-proposals/blob/master/proposals/0024-no-kind-vars.rst
Fixes Trac #16334, Trac #16315
With this patch, scoping rules for type and kind variables have been
unified: kind variables no longer receieve special treatment. This
simplifies both the language and the implementation.
User-facing changes
-------------------
* Kind variables are no longer implicitly quantified when an explicit
forall is used:
p :: Proxy (a :: k) -- still accepted
p :: forall k a. Proxy (a :: k) -- still accepted
p :: forall a. Proxy (a :: k) -- no longer accepted
In other words, now we adhere to the "forall-or-nothing" rule more
strictly.
Related function: RnTypes.rnImplicitBndrs
* The -Wimplicit-kind-vars warning has been deprecated.
* Kind variables are no longer implicitly quantified in constructor
declarations:
data T a = T1 (S (a :: k) | forall (b::k). T2 (S b) -- no longer accepted
data T (a :: k) = T1 (S (a :: k) | forall (b::k). T2 (S b) -- still accepted
Related function: RnTypes.extractRdrKindSigVars
* Implicitly quantified kind variables are no longer put in front of
other variables:
f :: Proxy (a :: k) -> Proxy (b :: j)
f :: forall k j (a :: k) (b :: j). Proxy a -> Proxy b -- old order
f :: forall k (a :: k) j (b :: j). Proxy a -> Proxy b -- new order
This is a breaking change for users of TypeApplications. Note that
we still respect the dpendency order: 'k' before 'a', 'j' before 'b'.
See "Ordering of specified variables" in the User's Guide.
Related function: RnTypes.rnImplicitBndrs
* In type synonyms and type family equations, free variables on the RHS
are no longer implicitly quantified unless used in an outermost kind
annotation:
type T = Just (Nothing :: Maybe a) -- no longer accepted
type T = Just Nothing :: Maybe (Maybe a) -- still accepted
The latter form is a workaround due to temporary lack of an explicit
quantification method. Ideally, we would write something along these
lines:
type T @a = Just (Nothing :: Maybe a)
Related function: RnTypes.extractHsTyRdrTyVarsKindVars
* Named wildcards in kinds are fixed (Trac #16334):
x :: (Int :: _t) -- this compiles, infers (_t ~ Type)
Related function: RnTypes.partition_nwcs
Implementation notes
--------------------
* One of the key changes is the removal of FKTV in RnTypes:
- data FreeKiTyVars = FKTV { fktv_kis :: [Located RdrName]
- , fktv_tys :: [Located RdrName] }
+ type FreeKiTyVars = [Located RdrName]
We used to keep track of type and kind variables separately, but
now that they are on equal footing when it comes to scoping, we
can put them in the same list.
* extract_lty and family are no longer parametrized by TypeOrKind,
as we now do not distinguish kind variables from type variables.
* PatSynExPE and the related Note [Pattern synonym existentials do not scope]
have been removed (Trac #16315). With no implicit kind quantification,
we can no longer trigger the error.
* reportFloatingKvs and the related Note [Free-floating kind vars]
have been removed. With no implicit kind quantification,
we can no longer trigger the error.
>---------------------------------------------------------------
5bc195b1fe788e9a900a15fbe473967850517c3e
compiler/main/DynFlags.hs | 4 +-
compiler/rename/RnSource.hs | 16 +-
compiler/rename/RnTypes.hs | 480 +++++++++------------
compiler/typecheck/TcHsType.hs | 116 -----
compiler/typecheck/TcPatSyn.hs | 51 ---
compiler/typecheck/TcRnTypes.hs | 5 -
compiler/typecheck/TcSplice.hs | 2 +-
compiler/typecheck/TcTyClsDecls.hs | 13 +-
docs/users_guide/8.10.1-notes.rst | 28 ++
docs/users_guide/glasgow_exts.rst | 112 +++--
docs/users_guide/using-warnings.rst | 53 ---
testsuite/tests/codeGen/should_fail/T13233.hs | 4 +-
.../tests/dependent/should_compile/T15264.stderr | 10 -
testsuite/tests/dependent/should_compile/all.T | 1 -
.../tests/dependent/should_fail/BadTelescope2.hs | 2 +-
.../dependent/should_fail/BadTelescope2.stderr | 6 +-
.../{should_compile => should_fail}/T15264.hs | 1 -
.../tests/dependent/should_fail/T15264.stderr | 6 +
testsuite/tests/dependent/should_fail/T15825.hs | 4 +-
.../tests/dependent/should_fail/T15825.stderr | 2 +-
testsuite/tests/dependent/should_fail/all.T | 1 +
testsuite/tests/ghci/scripts/T7873.stderr | 8 +-
testsuite/tests/ghci/scripts/T9293.stdout | 4 -
testsuite/tests/ghci/scripts/ghci024.stdout | 1 -
testsuite/tests/ghci/scripts/ghci057.stdout | 4 -
.../should_compile/ExplicitForAllFams1.hs | 2 +-
.../parser/should_compile/DumpRenamedAst.stderr | 4 +-
.../partial-sigs/should_compile/T15039a.stderr | 2 +-
.../partial-sigs/should_compile/T15039b.stderr | 2 +-
.../partial-sigs/should_compile/T15039c.stderr | 2 +-
.../partial-sigs/should_compile/T15039d.stderr | 2 +-
.../tests/partial-sigs/should_compile/T16334.hs | 6 +
.../partial-sigs/should_compile/T16334.stderr | 4 +
testsuite/tests/partial-sigs/should_compile/all.T | 1 +
.../{should_fail => should_compile}/T14498.hs | 4 +-
testsuite/tests/patsyn/should_compile/all.T | 1 +
testsuite/tests/patsyn/should_fail/T14507.hs | 2 +-
testsuite/tests/patsyn/should_fail/all.T | 1 -
testsuite/tests/polykinds/BadKindVar.hs | 2 +-
testsuite/tests/polykinds/BadKindVar.stderr | 2 +-
testsuite/tests/polykinds/KindVarOrder.script | 9 +
testsuite/tests/polykinds/KindVarOrder.stdout | 5 +
testsuite/tests/polykinds/T10503.hs | 2 +-
testsuite/tests/polykinds/T10503.stderr | 6 +-
testsuite/tests/polykinds/T13985.stderr | 28 +-
testsuite/tests/polykinds/T14561.hs | 2 +-
testsuite/tests/polykinds/T14563.hs | 2 +-
testsuite/tests/polykinds/T14846.stderr | 12 +-
testsuite/tests/polykinds/T14887a.hs | 8 +-
testsuite/tests/polykinds/T8616.hs | 4 +-
testsuite/tests/polykinds/T8616.stderr | 2 +-
testsuite/tests/polykinds/T9144.hs | 2 +-
testsuite/tests/polykinds/all.T | 1 +
testsuite/tests/typecheck/should_compile/T13343.hs | 2 +-
testsuite/tests/typecheck/should_fail/T12973.hs | 2 +-
.../tests/typecheck/should_fail/T13983.stderr | 8 +-
testsuite/tests/typecheck/should_fail/T15629.hs | 2 +-
.../tests/typecheck/should_fail/T15629.stderr | 10 +-
testsuite/tests/typecheck/should_fail/T15797.hs | 2 +-
59 files changed, 399 insertions(+), 681 deletions(-)
Diff suppressed because of size. To see it, use:
git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc 5bc195b1fe788e9a900a15fbe473967850517c3e
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