[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 9 commits: Do newtype unwrapping in the canonicaliser and rewriter
Marge Bot (@marge-bot)
gitlab at gitlab.haskell.org
Fri Jan 27 01:41:33 UTC 2023
Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC
Commits:
3e827c3f by Richard Eisenberg at 2023-01-26T20:06:53-05:00
Do newtype unwrapping in the canonicaliser and rewriter
See Note [Unwrap newtypes first], which has the details.
Close #22519.
- - - - -
b3ef5c89 by doyougnu at 2023-01-26T20:07:48-05:00
tryFillBuffer: strictify
more speculative bangs
- - - - -
d0d7ba0f by Vladislav Zavialov at 2023-01-26T20:08:25-05:00
base: NoImplicitPrelude in Data.Void and Data.Kind
This change removes an unnecessary dependency on Prelude
from two modules in the base package.
- - - - -
fa1db923 by Matthew Pickering at 2023-01-26T20:09:00-05:00
ci: Add ubuntu18_04 nightly and release jobs
This adds release jobs for ubuntu18_04 which uses glibc 2.27 which is
older than the 2.28 which is used by Rocky8 bindists.
Ticket #22268
- - - - -
807310a1 by Matthew Pickering at 2023-01-26T20:09:00-05:00
rel-eng: Add missing rocky8 bindist
We intend to release rocky8 bindist so the fetching script needs to know
about them.
- - - - -
c7116b10 by Ben Gamari at 2023-01-26T20:09:35-05:00
base: Make changelog proposal references more consistent
Addresses #22773.
- - - - -
6932cfc7 by Sylvain Henry at 2023-01-26T20:10:27-05:00
Fix spurious change from !9568
- - - - -
e6e97f8e by Ben Gamari at 2023-01-26T20:41:11-05:00
rts: Use C11-compliant static assertion syntax
Previously we used `static_assert` which is only available in C23. By
contrast, C11 only provides `_Static_assert`.
Fixes #22777
- - - - -
26b820e5 by Andrei Borzenkov at 2023-01-26T20:41:15-05:00
Replace errors from badOrigBinding with new one (#22839)
Problem: in 02279a9c the type-level [] syntax was changed from a built-in name
to an alias for the GHC.Types.List constructor. badOrigBinding assumes that if
a name is not built-in then it must have come from TH quotation, but this is
not necessarily the case with [].
The outdated assumption in badOrigBinding leads to incorrect error messages.
This code:
data []
Fails with "Cannot redefine a Name retrieved by a Template Haskell quote: []"
Unfortunately, there is not enough information in RdrName to directly determine
if the name was constructed via TH or by the parser, so this patch changes the
error message instead.
It unifies TcRnIllegalBindingOfBuiltIn and TcRnNameByTemplateHaskellQuote
into a new error TcRnBindingOfExistingName and changes its wording to avoid
guessing the origin of the name.
- - - - -
28 changed files:
- .gitlab-ci.yml
- .gitlab/gen_ci.hs
- .gitlab/jobs.yaml
- .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Rename/Env.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Solver/Canonical.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/Solver/Rewrite.hs
- compiler/GHC/Tc/Types.hs
- compiler/GHC/Types/Error/Codes.hs
- hadrian/src/Settings/Builders/RunTest.hs
- libraries/base/Data/Kind.hs
- libraries/base/Data/Void.hs
- libraries/base/GHC/Foreign.hs
- libraries/base/changelog.md
- rts/include/Rts.h
- testsuite/tests/rename/should_fail/T14907b.stderr
- + testsuite/tests/rename/should_fail/T22839.hs
- + testsuite/tests/rename/should_fail/T22839.stderr
- testsuite/tests/rename/should_fail/all.T
- testsuite/tests/rename/should_fail/rnfail042.stderr
- testsuite/tests/th/T13968.stderr
- + testsuite/tests/typecheck/should_compile/T22519.hs
- testsuite/tests/typecheck/should_compile/all.T
Changes:
=====================================
.gitlab-ci.yml
=====================================
@@ -2,7 +2,7 @@ variables:
GIT_SSL_NO_VERIFY: "1"
# Commit of ghc/ci-images repository from which to pull Docker images
- DOCKER_REV: dd01591a50ea4e2aa3c106cf50ca54d38663f912
+ DOCKER_REV: 2d59d551647d102c4af44f257c520a94f04ea3f6
# Sequential version number of all cached things.
# Bump to invalidate GitLab CI cache.
=====================================
.gitlab/gen_ci.hs
=====================================
@@ -112,6 +112,7 @@ data LinuxDistro
= Debian11 | Debian10 | Debian9
| Fedora33
| Ubuntu2004
+ | Ubuntu1804
| Centos7
| Alpine
| Rocky8
@@ -270,6 +271,7 @@ distroName Debian11 = "deb11"
distroName Debian10 = "deb10"
distroName Debian9 = "deb9"
distroName Fedora33 = "fedora33"
+distroName Ubuntu1804 = "ubuntu18_04"
distroName Ubuntu2004 = "ubuntu20_04"
distroName Centos7 = "centos7"
distroName Alpine = "alpine3_12"
@@ -860,6 +862,7 @@ job_groups =
-- We still build Deb9 bindists for now due to Ubuntu 18 and Linux Mint 19
-- not being at EOL until April 2023 and they still need tinfo5.
, disableValidate (standardBuildsWithConfig Amd64 (Linux Debian9) (splitSectionsBroken vanilla))
+ , disableValidate (standardBuilds Amd64 (Linux Ubuntu1804))
, disableValidate (standardBuilds Amd64 (Linux Ubuntu2004))
, disableValidate (standardBuilds Amd64 (Linux Rocky8))
, disableValidate (standardBuildsWithConfig Amd64 (Linux Centos7) (splitSectionsBroken vanilla))
=====================================
.gitlab/jobs.yaml
=====================================
@@ -1872,6 +1872,65 @@
"XZ_OPT": "-9"
}
},
+ "nightly-x86_64-linux-ubuntu18_04-validate": {
+ "after_script": [
+ ".gitlab/ci.sh save_cache",
+ ".gitlab/ci.sh clean",
+ "cat ci_timings"
+ ],
+ "allow_failure": false,
+ "artifacts": {
+ "expire_in": "8 weeks",
+ "paths": [
+ "ghc-x86_64-linux-ubuntu18_04-validate.tar.xz",
+ "junit.xml"
+ ],
+ "reports": {
+ "junit": "junit.xml"
+ },
+ "when": "always"
+ },
+ "cache": {
+ "key": "x86_64-linux-ubuntu18_04-$CACHE_REV",
+ "paths": [
+ "cabal-cache",
+ "toolchain"
+ ]
+ },
+ "dependencies": [],
+ "image": "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-ubuntu18_04:$DOCKER_REV",
+ "needs": [
+ {
+ "artifacts": false,
+ "job": "hadrian-ghc-in-ghci"
+ }
+ ],
+ "rules": [
+ {
+ "if": "($CI_MERGE_REQUEST_LABELS !~ /.*fast-ci.*/) && ($RELEASE_JOB != \"yes\") && ($NIGHTLY) && (\"true\" == \"true\") && (\"true\" == \"true\") && (\"true\" == \"true\")",
+ "when": "on_success"
+ }
+ ],
+ "script": [
+ "sudo chown ghc:ghc -R .",
+ ".gitlab/ci.sh setup",
+ ".gitlab/ci.sh configure",
+ ".gitlab/ci.sh build_hadrian",
+ ".gitlab/ci.sh test_hadrian"
+ ],
+ "stage": "full-build",
+ "tags": [
+ "x86_64-linux"
+ ],
+ "variables": {
+ "BIGNUM_BACKEND": "gmp",
+ "BIN_DIST_NAME": "ghc-x86_64-linux-ubuntu18_04-validate",
+ "BUILD_FLAVOUR": "validate",
+ "CONFIGURE_ARGS": "",
+ "TEST_ENV": "x86_64-linux-ubuntu18_04-validate",
+ "XZ_OPT": "-9"
+ }
+ },
"nightly-x86_64-linux-ubuntu20_04-validate": {
"after_script": [
".gitlab/ci.sh save_cache",
@@ -3038,6 +3097,66 @@
"XZ_OPT": "-9"
}
},
+ "release-x86_64-linux-ubuntu18_04-release": {
+ "after_script": [
+ ".gitlab/ci.sh save_cache",
+ ".gitlab/ci.sh clean",
+ "cat ci_timings"
+ ],
+ "allow_failure": false,
+ "artifacts": {
+ "expire_in": "1 year",
+ "paths": [
+ "ghc-x86_64-linux-ubuntu18_04-release.tar.xz",
+ "junit.xml"
+ ],
+ "reports": {
+ "junit": "junit.xml"
+ },
+ "when": "always"
+ },
+ "cache": {
+ "key": "x86_64-linux-ubuntu18_04-$CACHE_REV",
+ "paths": [
+ "cabal-cache",
+ "toolchain"
+ ]
+ },
+ "dependencies": [],
+ "image": "registry.gitlab.haskell.org/ghc/ci-images/x86_64-linux-ubuntu18_04:$DOCKER_REV",
+ "needs": [
+ {
+ "artifacts": false,
+ "job": "hadrian-ghc-in-ghci"
+ }
+ ],
+ "rules": [
+ {
+ "if": "($CI_MERGE_REQUEST_LABELS !~ /.*fast-ci.*/) && ($RELEASE_JOB == \"yes\") && ($NIGHTLY == null) && (\"true\" == \"true\") && (\"true\" == \"true\") && (\"true\" == \"true\")",
+ "when": "on_success"
+ }
+ ],
+ "script": [
+ "sudo chown ghc:ghc -R .",
+ ".gitlab/ci.sh setup",
+ ".gitlab/ci.sh configure",
+ ".gitlab/ci.sh build_hadrian",
+ ".gitlab/ci.sh test_hadrian"
+ ],
+ "stage": "full-build",
+ "tags": [
+ "x86_64-linux"
+ ],
+ "variables": {
+ "BIGNUM_BACKEND": "gmp",
+ "BIN_DIST_NAME": "ghc-x86_64-linux-ubuntu18_04-release",
+ "BUILD_FLAVOUR": "release",
+ "CONFIGURE_ARGS": "",
+ "IGNORE_PERF_FAILURES": "all",
+ "TEST_ENV": "x86_64-linux-ubuntu18_04-release",
+ "XZ_OPT": "-9"
+ }
+ },
"release-x86_64-linux-ubuntu20_04-release": {
"after_script": [
".gitlab/ci.sh save_cache",
=====================================
.gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py
=====================================
@@ -16,7 +16,9 @@ def job_triple(job_name):
bindists = {
'release-x86_64-windows-release': 'x86_64-unknown-mingw32',
'release-x86_64-windows-int_native-release': 'x86_64-unknown-mingw32-int_native',
+ 'release-x86_64-rocky8-release': 'x86_64-rocky8-linux',
'release-x86_64-ubuntu20_04-release': 'x86_64-ubuntu20_04-linux',
+ 'release-x86_64-ubuntu18_04-release': 'x86_64-ubuntu18_04-linux',
'release-x86_64-linux-fedora33-release+debug_info': 'x86_64-fedora33-linux-dwarf',
'release-x86_64-linux-fedora33-release': 'x86_64-fedora33-linux',
'release-x86_64-linux-fedora27-release': 'x86_64-fedora27-linux',
=====================================
compiler/GHC/Core/Coercion.hs
=====================================
@@ -1791,7 +1791,7 @@ topNormaliseNewType_maybe :: Type -> Maybe (Coercion, Type)
--
-- > topNormaliseNewType_maybe rec_nts ty = Just (co, ty')
--
--- then (a) @co : ty ~ ty'@.
+-- then (a) @co : ty ~R ty'@.
-- (b) ty' is not a newtype.
--
-- The function returns @Nothing@ for non- at newtypes@,
=====================================
compiler/GHC/Rename/Env.hs
=====================================
@@ -187,7 +187,7 @@ newTopSrcBinder (L loc rdr_name)
if isExternalName name then
do { this_mod <- getModule
; unless (this_mod == nameModule name)
- (addErrAt (locA loc) (badOrigBinding rdr_name))
+ (addErrAt (locA loc) (TcRnBindingOfExistingName rdr_name))
; return name }
else -- See Note [Binders in Template Haskell] in "GHC.ThToHs"
do { this_mod <- getModule
@@ -196,7 +196,7 @@ newTopSrcBinder (L loc rdr_name)
| Just (rdr_mod, rdr_occ) <- isOrig_maybe rdr_name
= do { this_mod <- getModule
; unless (rdr_mod == this_mod || rdr_mod == rOOT_MAIN)
- (addErrAt (locA loc) (badOrigBinding rdr_name))
+ (addErrAt (locA loc) (TcRnBindingOfExistingName rdr_name))
-- When reading External Core we get Orig names as binders,
-- but they should agree with the module gotten from the monad
--
@@ -205,7 +205,7 @@ newTopSrcBinder (L loc rdr_name)
-- the constructor is parsed as a type, and then GHC.Parser.PostProcess.tyConToDataCon
-- uses setRdrNameSpace to make it into a data constructors. At that point
-- the nice Exact name for the TyCon gets swizzled to an Orig name.
- -- Hence the badOrigBinding error message.
+ -- Hence the TcRnBindingOfExistingName error message.
--
-- MP 2022: I suspect this code path is never called for `rOOT_MAIN` anymore
@@ -2118,13 +2118,3 @@ lookupQualifiedDoName ctxt std_name
= case qualifiedDoModuleName_maybe ctxt of
Nothing -> lookupSyntaxName std_name
Just modName -> lookupNameWithQualifier std_name modName
-
-
--- Error messages
-
-badOrigBinding :: RdrName -> TcRnMessage
-badOrigBinding name
- | Just _ <- isBuiltInOcc_maybe occ = TcRnIllegalBindingOfBuiltIn occ
- | otherwise = TcRnNameByTemplateHaskellQuote name
- where
- occ = rdrNameOcc $ filterCTuple name
=====================================
compiler/GHC/Tc/Errors/Ppr.hs
=====================================
@@ -25,7 +25,7 @@ module GHC.Tc.Errors.Ppr
import GHC.Prelude
import GHC.Builtin.Names
-import GHC.Builtin.Types ( boxedRepDataConTyCon, tYPETyCon )
+import GHC.Builtin.Types ( boxedRepDataConTyCon, tYPETyCon, filterCTuple )
import GHC.Core.Coercion
import GHC.Core.Unify ( tcMatchTys )
@@ -968,10 +968,6 @@ instance Diagnostic TcRnMessage where
-> mkSimpleDecorated $
text "You cannot SPECIALISE" <+> quotes (ppr name)
<+> text "because its definition is not visible in this module"
- TcRnNameByTemplateHaskellQuote name -> mkSimpleDecorated $
- text "Cannot redefine a Name retrieved by a Template Haskell quote:" <+> ppr name
- TcRnIllegalBindingOfBuiltIn name -> mkSimpleDecorated $
- text "Illegal binding of built-in syntax:" <+> ppr name
TcRnPragmaWarning {pragma_warning_occ, pragma_warning_msg, pragma_warning_import_mod, pragma_warning_defined_mod}
-> mkSimpleDecorated $
sep [ sep [ text "In the use of"
@@ -1238,6 +1234,8 @@ instance Diagnostic TcRnMessage where
Left gbl_names -> vcat (map (\name -> quotes (ppr $ grePrintableName name) <+> pprNameProvenance name) gbl_names)
Right lcl_name -> quotes (ppr lcl_name) <+> text "defined at"
<+> ppr (nameSrcLoc lcl_name)
+ TcRnBindingOfExistingName name -> mkSimpleDecorated $
+ text "Illegal binding of an existing name:" <+> ppr (filterCTuple name)
diagnosticReason = \case
TcRnUnknownMessage m
@@ -1552,10 +1550,6 @@ instance Diagnostic TcRnMessage where
-> WarningWithoutFlag
TcRnSpecialiseNotVisible{}
-> WarningWithoutFlag
- TcRnNameByTemplateHaskellQuote{}
- -> ErrorWithoutFlag
- TcRnIllegalBindingOfBuiltIn{}
- -> ErrorWithoutFlag
TcRnPragmaWarning{}
-> WarningWithFlag Opt_WarnWarningsDeprecations
TcRnIllegalHsigDefaultMethods{}
@@ -1646,6 +1640,8 @@ instance Diagnostic TcRnMessage where
-> ErrorWithoutFlag
TcRnCapturedTermName{}
-> WarningWithFlag Opt_WarnTermVariableCapture
+ TcRnBindingOfExistingName{}
+ -> ErrorWithoutFlag
diagnosticHints = \case
TcRnUnknownMessage m
@@ -1962,10 +1958,6 @@ instance Diagnostic TcRnMessage where
-> noHints
TcRnSpecialiseNotVisible name
-> [SuggestSpecialiseVisibilityHints name]
- TcRnNameByTemplateHaskellQuote{}
- -> noHints
- TcRnIllegalBindingOfBuiltIn{}
- -> noHints
TcRnPragmaWarning{}
-> noHints
TcRnIllegalHsigDefaultMethods{}
@@ -2059,6 +2051,8 @@ instance Diagnostic TcRnMessage where
-> [suggestExtension LangExt.TupleSections]
TcRnCapturedTermName{}
-> [SuggestRenameTypeVariable]
+ TcRnBindingOfExistingName{}
+ -> noHints
diagnosticCode = constructorCode
=====================================
compiler/GHC/Tc/Errors/Types.hs
=====================================
@@ -2193,32 +2193,6 @@ data TcRnMessage where
-}
TcRnSpecialiseNotVisible :: !Name -> TcRnMessage
- {- TcRnNameByTemplateHaskellQuote is an error that occurs when one tries
- to use a Template Haskell splice to define a top-level identifier with
- an already existing name.
-
- (See issue #13968 (closed) on GHC's issue tracker for more details)
-
- Example(s):
-
- $(pure [ValD (VarP 'succ) (NormalB (ConE 'True)) []])
-
- Test cases:
- T13968
- -}
- TcRnNameByTemplateHaskellQuote :: !RdrName -> TcRnMessage
-
- {- TcRnIllegalBindingOfBuiltIn is an error that occurs when one uses built-in
- syntax for data constructors or class names.
-
- Use an OccName here because we don't want to print Prelude.(,)
-
- Test cases:
- rename/should_fail/T14907b
- rename/should_fail/rnfail042
- -}
- TcRnIllegalBindingOfBuiltIn :: !OccName -> TcRnMessage
-
{- TcRnPragmaWarning is a warning that can happen when usage of something
is warned or deprecated by pragma.
@@ -2773,6 +2747,22 @@ data TcRnMessage where
-}
TcRnSectionWithoutParentheses :: HsExpr GhcPs -> TcRnMessage
+ {- TcRnBindingOfExistingName is an error triggered by an attempt to rebind
+ built-in syntax, punned list or tuple syntax, or a name quoted via Template Haskell.
+
+ Examples:
+
+ data []
+ data (->)
+ $(pure [ValD (VarP 'succ) (NormalB (ConE 'True)) []])
+
+ Test cases: rename/should_fail/T14907b
+ rename/should_fail/T22839
+ rename/should_fail/rnfail042
+ th/T13968
+ -}
+ TcRnBindingOfExistingName :: RdrName -> TcRnMessage
+
deriving Generic
-- | Things forbidden in @type data@ declarations.
=====================================
compiler/GHC/Tc/Instance/Family.hs
=====================================
@@ -519,16 +519,16 @@ tcLookupDataFamInst_maybe fam_inst_envs tc tc_args
= Nothing
-- | 'tcTopNormaliseNewTypeTF_maybe' gets rid of top-level newtypes,
--- potentially looking through newtype /instances/.
+-- potentially looking through newtype /instances/ and type synonyms.
--
-- It is only used by the type inference engine (specifically, when
-- solving representational equality), and hence it is careful to unwrap
-- only if the relevant data constructor is in scope. That's why
-- it gets a GlobalRdrEnv argument.
--
--- It is careful not to unwrap data/newtype instances if it can't
--- continue unwrapping. Such care is necessary for proper error
--- messages.
+-- It is careful not to unwrap data/newtype instances nor synonyms
+-- if it can't continue unwrapping. Such care is necessary for proper
+-- error messages.
--
-- It does not look through type families.
-- It does not normalise arguments to a tycon.
=====================================
compiler/GHC/Tc/Solver/Canonical.hs
=====================================
@@ -61,7 +61,6 @@ import GHC.Types.Basic
import qualified Data.Semigroup as S
import Data.Bifunctor ( bimap )
-import Data.Foldable ( traverse_ )
{-
************************************************************************
@@ -1085,7 +1084,7 @@ can_eq_nc' _rewritten _rdr_env _envs ev eq_rel
-- Decompose type constructor applications
-- NB: we have expanded type synonyms already
-can_eq_nc' _rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+can_eq_nc' rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
| Just (tc1, tys1) <- tcSplitTyConApp_maybe ty1
, Just (tc2, tys2) <- tcSplitTyConApp_maybe ty2
-- we want to catch e.g. Maybe Int ~ (Int -> Int) here for better
@@ -1093,7 +1092,7 @@ can_eq_nc' _rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
-- hence no direct match on TyConApp
, not (isTypeFamilyTyCon tc1)
, not (isTypeFamilyTyCon tc2)
- = canTyConApp ev eq_rel tc1 tys1 tc2 tys2
+ = canTyConApp rewritten ev eq_rel tc1 tys1 tc2 tys2
can_eq_nc' _rewritten _rdr_env _envs ev eq_rel
s1@(ForAllTy (Bndr _ vis1) _) _
@@ -1115,11 +1114,8 @@ can_eq_nc' True _rdr_env _envs ev NomEq ty1 _ ty2 _
-------------------
-- No similarity in type structure detected. Rewrite and try again.
-can_eq_nc' False rdr_env envs ev eq_rel _ ps_ty1 _ ps_ty2
- = do { (redn1@(Reduction _ xi1), rewriters1) <- rewrite ev ps_ty1
- ; (redn2@(Reduction _ xi2), rewriters2) <- rewrite ev ps_ty2
- ; new_ev <- rewriteEqEvidence (rewriters1 S.<> rewriters2) ev NotSwapped redn1 redn2
- ; can_eq_nc' True rdr_env envs new_ev eq_rel xi1 xi1 xi2 xi2 }
+can_eq_nc' False _rdr_env _envs ev eq_rel _ ps_ty1 _ ps_ty2
+ = rewrite_and_try_again ev eq_rel ps_ty1 ps_ty2
----------------------------
-- Look for a canonical LHS. See Note [Canonical LHS].
@@ -1157,6 +1153,16 @@ can_eq_nc' True _rdr_env _envs ev eq_rel _ ps_ty1 _ ps_ty2
-- No need to call canEqFailure/canEqHardFailure because they
-- rewrite, and the types involved here are already rewritten
+-- Rewrite the two types and try again
+rewrite_and_try_again :: CtEvidence -> EqRel -> TcType -> TcType -> TcS (StopOrContinue Ct)
+rewrite_and_try_again ev eq_rel ty1 ty2
+ = do { (redn1@(Reduction _ xi1), rewriters1) <- rewrite ev ty1
+ ; (redn2@(Reduction _ xi2), rewriters2) <- rewrite ev ty2
+ ; new_ev <- rewriteEqEvidence (rewriters1 S.<> rewriters2) ev NotSwapped redn1 redn2
+ ; rdr_env <- getGlobalRdrEnvTcS
+ ; envs <- getFamInstEnvs
+ ; can_eq_nc' True rdr_env envs new_ev eq_rel xi1 xi1 xi2 xi2 }
+
{- Note [Unsolved equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If we have an unsolved equality like
@@ -1379,45 +1385,84 @@ zonk_eq_types = go
combine_rev f (Right tys) (Left elt) = Left (f <$> elt <*> pure tys)
combine_rev f (Right tys) (Right ty) = Right (f ty tys)
-{- See Note [Unwrap newtypes first]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+{- Note [Unwrap newtypes first]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
See also Note [Decomposing newtype equalities]
Consider
newtype N m a = MkN (m a)
-Then N will get a conservative, Nominal role for its second parameter 'a',
+N will get a conservative, Nominal role for its second parameter 'a',
because it appears as an argument to the unknown 'm'. Now consider
[W] N Maybe a ~R# N Maybe b
-If we decompose, we'll get
+If we /decompose/, we'll get
[W] a ~N# b
-But if instead we unwrap we'll get
+But if instead we /unwrap/ we'll get
[W] Maybe a ~R# Maybe b
which in turn gives us
[W] a ~R# b
which is easier to satisfy.
-Bottom line: unwrap newtypes before decomposing them!
-c.f. #9123 comment:52,53 for a compelling example.
+Conclusion: we must unwrap newtypes before decomposing them. This happens
+in `can_eq_newtype_nc`
-Note [Newtypes can blow the stack]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
+But even this is challenging. Here are two cases to consider:
- newtype X = MkX (Int -> X)
- newtype Y = MkY (Int -> Y)
+Case 1:
+
+ newtype Age = MkAge Int
+ [G] c
+ [W] w1 :: IO Age ~R# IO Int
-and now wish to prove
+Case 2:
- [W] X ~R Y
+ newtype A = MkA [A]
+ [W] A ~R# [A]
-This Wanted will loop, expanding out the newtypes ever deeper looking
-for a solid match or a solid discrepancy. Indeed, there is something
-appropriate to this looping, because X and Y *do* have the same representation,
-in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
-coercion will ever witness it. This loop won't actually cause GHC to hang,
-though, because we check our depth when unwrapping newtypes.
+For Case 1, recall that IO is an abstract newtype. Then read Note
+[Decomposing newtype equalities]. According to that Note, we should not
+decompose w1, because we have an Irred Given. Yet we still want to solve
+the wanted! We can do so by unwrapping the (non-abstract) Age newtype
+underneath the IO, giving
+ [W] w2 :: IO Int ~R# IO Int
+ w1 = (IO unwrap-Age ; w2)
+where unwrap-Age :: Age ~R# Int. Now we case solve w2 by reflexivity;
+see Note [Eager reflexivity check].
+
+Conclusion: unwrap newtypes (deeply, inside types) in the rewriter:
+specifically in GHC.Tc.Solver.Rewrite.rewrite_newtype_app.
+
+Yet for Case 2, deep rewriting would be a disaster: we would loop.
+ [W] A ~R# [A] ---> {unwrap}
+ [W] [A] ~R# [[A]]
+ ---> {decompose}
+ [W] A ~R# [A]
+
+In this case, we just want to unwrap newtypes /at the top level/, allowing us
+to succeed via Note [Eager reflexivity check]:
+ [W] A ~R# [A] ---> {unwrap at top level only}
+ [W] [A] ~R# [A]
+ ---> {reflexivity} success
+
+Conclusion: to satisfy Case 1 and Case 2, we unwrap
+* /both/ at top level, in can_eq_nc'
+* /and/ deeply, in the rewriter, rewrite_newtype_app
+
+The former unwraps outer newtypes (when the data constructor is in scope).
+The latter unwraps deeply -- but it won't be invoked in Case 2, when we can
+recognize an equality between the types [A] and [A] before rewriting
+deeply.
+
+This "before" business is delicate -- there is still a real risk of a loop
+in the type checker with recursive newtypes -- but I think we're doomed to do
+*something* delicate, as we're really trying to solve for equirecursive
+type equality. Bottom line for users: recursive newtypes are dangerous.
+See also Section 5.3.1 and 5.3.4 of
+"Safe Zero-cost Coercions for Haskell" (JFP 2016).
+
+Another approach -- which we ultimately decided against -- is described in
+Note [Decomposing newtypes a bit more aggressively].
Note [Eager reflexivity check]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1462,28 +1507,22 @@ can_eq_newtype_nc ev swapped ty1 ((gres, co1), ty1') ty2 ps_ty2
= do { traceTcS "can_eq_newtype_nc" $
vcat [ ppr ev, ppr swapped, ppr co1, ppr gres, ppr ty1', ppr ty2 ]
- -- check for blowing our stack:
+ -- Check for blowing our stack, and increase the depth
-- See Note [Newtypes can blow the stack]
- ; checkReductionDepth (ctEvLoc ev) ty1
+ ; let loc = ctEvLoc ev
+ ev' = ev `setCtEvLoc` bumpCtLocDepth loc
+ ; checkReductionDepth loc ty1
-- Next, we record uses of newtype constructors, since coercing
-- through newtypes is tantamount to using their constructors.
- ; addUsedGREs gre_list
- -- If a newtype constructor was imported, don't warn about not
- -- importing it...
- ; traverse_ keepAlive $ map greMangledName gre_list
- -- ...and similarly, if a newtype constructor was defined in the same
- -- module, don't warn about it being unused.
- -- See Note [Tracking unused binding and imports] in GHC.Tc.Utils.
+ ; recordUsedGREs gres
; let redn1 = mkReduction co1 ty1'
- ; new_ev <- rewriteEqEvidence emptyRewriterSet ev swapped
+ ; new_ev <- rewriteEqEvidence emptyRewriterSet ev' swapped
redn1
(mkReflRedn Representational ps_ty2)
; can_eq_nc False new_ev ReprEq ty1' ty1' ty2 ps_ty2 }
- where
- gre_list = bagToList gres
---------
-- ^ Decompose a type application.
@@ -1559,7 +1598,8 @@ canEqCast rewritten ev eq_rel swapped ty1 co1 ty2 ps_ty2
role = eqRelRole eq_rel
------------------------
-canTyConApp :: CtEvidence -> EqRel
+canTyConApp :: Bool -- True <=> the types have been rewritten
+ -> CtEvidence -> EqRel
-> TyCon -> [TcType]
-> TyCon -> [TcType]
-> TcS (StopOrContinue Ct)
@@ -1567,13 +1607,17 @@ canTyConApp :: CtEvidence -> EqRel
-- See Note [Decomposing Dependent TyCons and Processing Wanted Equalities]
-- Neither tc1 nor tc2 is a saturated funTyCon, nor a type family
-- But they can be data families.
-canTyConApp ev eq_rel tc1 tys1 tc2 tys2
+canTyConApp rewritten ev eq_rel tc1 tys1 tc2 tys2
| tc1 == tc2
, tys1 `equalLength` tys2
= do { inerts <- getTcSInerts
; if can_decompose inerts
then canDecomposableTyConAppOK ev eq_rel tc1 tys1 tys2
- else canEqFailure ev eq_rel ty1 ty2 }
+ else if rewritten
+ then canEqFailure ev eq_rel ty1 ty2
+ else rewrite_and_try_again ev eq_rel ty1 ty2 }
+ -- Why rewrite and try again? See Case 1
+ -- of Note [Unwrap newtypes first]
-- See Note [Skolem abstract data] in GHC.Core.Tycon
| tyConSkolem tc1 || tyConSkolem tc2
@@ -1851,8 +1895,12 @@ only about /completeness/.
Note [Decomposing newtypes a bit more aggressively]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-c.f. https://github.com/ghc-proposals/ghc-proposals/pull/549,
-issue #22441, and discussion on !9282.
+IMPORTANT: the ideas in this Note are *not* implemented. Instead, the
+current approach is detailed in Note [Unwrap newtypes first].
+For more details about the ideas in this Note see
+ * GHC propoosal: https://github.com/ghc-proposals/ghc-proposals/pull/549
+ * issue #22441
+ * discussion on !9282.
Consider [G] c, [W] (IO Int) ~R (IO Age)
where IO is abstract, and
@@ -2091,8 +2139,8 @@ canEqHardFailure :: CtEvidence
-- See Note [Make sure that insolubles are fully rewritten]
canEqHardFailure ev ty1 ty2
= do { traceTcS "canEqHardFailure" (ppr ty1 $$ ppr ty2)
- ; (redn1, rewriters1) <- rewrite ev ty1
- ; (redn2, rewriters2) <- rewrite ev ty2
+ ; (redn1, rewriters1) <- rewriteForErrors ev ty1
+ ; (redn2, rewriters2) <- rewriteForErrors ev ty2
; new_ev <- rewriteEqEvidence (rewriters1 S.<> rewriters2) ev NotSwapped redn1 redn2
; continueWith (mkIrredCt ShapeMismatchReason new_ev) }
@@ -3203,12 +3251,12 @@ rewriteEqEvidence new_rewriters old_ev swapped (Reduction lhs_co nlhs) (Reductio
= do { let new_tm = evCoercion ( mkSymCo lhs_co
`mkTransCo` maybeSymCo swapped (mkCoVarCo old_evar)
`mkTransCo` rhs_co)
- ; newGivenEvVar loc' (new_pred, new_tm) }
+ ; newGivenEvVar loc (new_pred, new_tm) }
| CtWanted { ctev_dest = dest
, ctev_rewriters = rewriters } <- old_ev
, let rewriters' = rewriters S.<> new_rewriters
- = do { (new_ev, hole_co) <- newWantedEq loc' rewriters'
+ = do { (new_ev, hole_co) <- newWantedEq loc rewriters'
(ctEvRole old_ev) nlhs nrhs
; let co = maybeSymCo swapped $
lhs_co
@@ -3228,12 +3276,7 @@ rewriteEqEvidence new_rewriters old_ev swapped (Reduction lhs_co nlhs) (Reductio
#endif
where
new_pred = mkTcEqPredLikeEv old_ev nlhs nrhs
-
- -- equality is like a type class. Bumping the depth is necessary because
- -- of recursive newtypes, where "reducing" a newtype can actually make
- -- it bigger. See Note [Newtypes can blow the stack].
loc = ctEvLoc old_ev
- loc' = bumpCtLocDepth loc
{-
************************************************************************
=====================================
compiler/GHC/Tc/Solver/Monad.hs
=====================================
@@ -25,7 +25,7 @@ module GHC.Tc.Solver.Monad (
updWorkListTcS,
pushLevelNoWorkList,
- runTcPluginTcS, addUsedGRE, addUsedGREs, keepAlive,
+ runTcPluginTcS, recordUsedGREs,
matchGlobalInst, TcM.ClsInstResult(..),
QCInst(..),
@@ -151,7 +151,7 @@ import GHC.Core.TyCon
import GHC.Types.Error ( mkPlainError, noHints )
import GHC.Types.Name
import GHC.Types.TyThing
-import GHC.Types.Name.Reader ( GlobalRdrEnv, GlobalRdrElt )
+import GHC.Types.Name.Reader
import GHC.Unit.Module ( HasModule, getModule, extractModule )
import qualified GHC.Rename.Env as TcM
@@ -175,7 +175,8 @@ import Control.Monad
import GHC.Utils.Monad
import Data.IORef
import GHC.Exts (oneShot)
-import Data.List ( mapAccumL, partition, find )
+import Data.List ( mapAccumL, partition )
+import Data.Foldable
#if defined(DEBUG)
import GHC.Data.Graph.Directed
@@ -1373,17 +1374,22 @@ tcLookupClass c = wrapTcS $ TcM.tcLookupClass c
tcLookupId :: Name -> TcS Id
tcLookupId n = wrapTcS $ TcM.tcLookupId n
--- Setting names as used (used in the deriving of Coercible evidence)
--- Too hackish to expose it to TcS? In that case somehow extract the used
--- constructors from the result of solveInteract
-addUsedGREs :: [GlobalRdrElt] -> TcS ()
-addUsedGREs gres = wrapTcS $ TcM.addUsedGREs gres
+-- Any use of this function is a bit suspect, because it violates the
+-- pure veneer of TcS. But it's just about warnings around unused imports
+-- and local constructors (GHC will issue fewer warnings than it otherwise
+-- might), so it's not worth losing sleep over.
+recordUsedGREs :: Bag GlobalRdrElt -> TcS ()
+recordUsedGREs gres
+ = do { wrapTcS $ TcM.addUsedGREs gre_list
+ -- If a newtype constructor was imported, don't warn about not
+ -- importing it...
+ ; wrapTcS $ traverse_ (TcM.keepAlive . greMangledName) gre_list }
+ -- ...and similarly, if a newtype constructor was defined in the same
+ -- module, don't warn about it being unused.
+ -- See Note [Tracking unused binding and imports] in GHC.Tc.Utils.
-addUsedGRE :: Bool -> GlobalRdrElt -> TcS ()
-addUsedGRE warn_if_deprec gre = wrapTcS $ TcM.addUsedGRE warn_if_deprec gre
-
-keepAlive :: Name -> TcS ()
-keepAlive = wrapTcS . TcM.keepAlive
+ where
+ gre_list = bagToList gres
-- Various smaller utilities [TODO, maybe will be absorbed in the instance matcher]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
=====================================
compiler/GHC/Tc/Solver/Rewrite.hs
=====================================
@@ -3,7 +3,7 @@
{-# LANGUAGE DeriveFunctor #-}
module GHC.Tc.Solver.Rewrite(
- rewrite, rewriteArgsNom,
+ rewrite, rewriteForErrors, rewriteArgsNom,
rewriteType
) where
@@ -42,6 +42,7 @@ import GHC.Builtin.Types (tYPETyCon)
import Data.List ( find )
import GHC.Data.List.Infinite (Infinite)
import qualified GHC.Data.List.Infinite as Inf
+import GHC.Tc.Instance.Family (tcTopNormaliseNewTypeTF_maybe)
{-
************************************************************************
@@ -223,6 +224,22 @@ rewrite ev ty
; traceTcS "rewrite }" (ppr $ reductionReducedType redn)
; return result }
+-- | See Note [Rewriting]
+-- This variant of 'rewrite' rewrites w.r.t. nominal equality only,
+-- as this is better than full rewriting for error messages. Specifically,
+-- we want to avoid unwrapping newtypes, as doing so can end up causing
+-- an otherwise-unnecessary stack overflow.
+rewriteForErrors :: CtEvidence -> TcType
+ -> TcS (Reduction, RewriterSet)
+rewriteForErrors ev ty
+ = do { traceTcS "rewriteForErrors {" (ppr ty)
+ ; result@(redn, rewriters) <-
+ runRewrite (ctEvLoc ev) (ctEvFlavour ev) NomEq (rewrite_one ty)
+ ; traceTcS "rewriteForErrors }" (ppr $ reductionReducedType redn)
+ ; return $ case ctEvEqRel ev of
+ NomEq -> result
+ ReprEq -> (mkSubRedn redn, rewriters) }
+
-- See Note [Rewriting]
rewriteArgsNom :: CtEvidence -> TyCon -> [TcType]
-> TcS (Reductions, RewriterSet)
@@ -482,16 +499,27 @@ rewrite_one (TyVarTy tv)
rewrite_one (AppTy ty1 ty2)
= rewrite_app_tys ty1 [ty2]
-rewrite_one (TyConApp tc tys)
+rewrite_one ty@(TyConApp tc tys)
-- If it's a type family application, try to reduce it
| isTypeFamilyTyCon tc
= rewrite_fam_app tc tys
- -- For * a normal data type application
- -- * data family application
- -- we just recursively rewrite the arguments.
| otherwise
- = rewrite_ty_con_app tc tys
+ = do { eq_rel <- getEqRel
+ ; if eq_rel == ReprEq
+
+ then -- Rewriting w.r.t. representational equality requires
+ -- unwrapping newtypes; see GHC.Tc.Solver.Canonical.
+ -- Note [Unwrap newtypes first]
+ -- NB: try rewrite_newtype_app even when tc isn't a newtype;
+ -- the allows the possibility of having a newtype buried under
+ -- a synonym. Needed for e.g. T12067.
+ rewrite_newtype_app ty
+
+ else -- For * a normal data type application
+ -- * data family application
+ -- we just recursively rewrite the arguments.
+ rewrite_ty_con_app tc tys }
rewrite_one (FunTy { ft_af = vis, ft_mult = mult, ft_arg = ty1, ft_res = ty2 })
= do { arg_redn <- rewrite_one ty1
@@ -650,7 +678,43 @@ rewrite_vector ki roles tys
fvs = tyCoVarsOfType ki
{-# INLINE rewrite_vector #-}
-{-
+-- Rewrite a (potential) newtype application
+-- Precondition: the ambient EqRel is ReprEq
+-- Precondition: the type is a TyConApp
+-- See Note [Newtypes can blow the stack]
+rewrite_newtype_app :: TcType -> RewriteM Reduction
+rewrite_newtype_app ty@(TyConApp tc tys)
+ = do { rdr_env <- liftTcS getGlobalRdrEnvTcS
+ ; tf_envs <- liftTcS getFamInstEnvs
+ ; case (tcTopNormaliseNewTypeTF_maybe tf_envs rdr_env ty) of
+ Nothing -> -- Non-newtype or abstract newtype
+ rewrite_ty_con_app tc tys
+
+ Just ((used_ctors, co), ty') -- co :: ty ~ ty'
+ -> do { liftTcS $ recordUsedGREs used_ctors
+ ; checkStackDepth ty
+ ; rewrite_reduction (Reduction co ty') } }
+
+rewrite_newtype_app other_ty = pprPanic "rewrite_newtype_app" (ppr other_ty)
+
+{- Note [Newtypes can blow the stack]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Suppose we have
+
+ newtype X = MkX (Int -> X)
+ newtype Y = MkY (Int -> Y)
+
+and now wish to prove
+
+ [W] X ~R Y
+
+This Wanted will loop, expanding out the newtypes ever deeper looking
+for a solid match or a solid discrepancy. Indeed, there is something
+appropriate to this looping, because X and Y *do* have the same representation,
+in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
+coercion will ever witness it. This loop won't actually cause GHC to hang,
+though, because we check our depth when unwrapping newtypes.
+
Note [Rewriting synonyms]
~~~~~~~~~~~~~~~~~~~~~~~~~~
Not expanding synonyms aggressively improves error messages, and
=====================================
compiler/GHC/Tc/Types.hs
=====================================
@@ -294,6 +294,7 @@ data RewriteEnv
-- ^ At what role are we rewriting?
--
-- See Note [Rewriter EqRels] in GHC.Tc.Solver.Rewrite
+
, re_rewriters :: !(TcRef RewriterSet) -- ^ See Note [Wanteds rewrite Wanteds]
}
-- RewriteEnv is mostly used in @GHC.Tc.Solver.Rewrite@, but it is defined
=====================================
compiler/GHC/Types/Error/Codes.hs
=====================================
@@ -468,8 +468,6 @@ type family GhcDiagnosticCode c = n | n -> c where
GhcDiagnosticCode "TcRnNonOverloadedSpecialisePragma" = 35827
GhcDiagnosticCode "TcRnSpecialiseNotVisible" = 85337
GhcDiagnosticCode "TcRnIllegalTypeOperatorDecl" = 50649
- GhcDiagnosticCode "TcRnNameByTemplateHaskellQuote" = 40027
- GhcDiagnosticCode "TcRnIllegalBindingOfBuiltIn" = 69639
GhcDiagnosticCode "TcRnIllegalHsigDefaultMethods" = 93006
GhcDiagnosticCode "TcRnBadGenericMethod" = 59794
@@ -502,6 +500,7 @@ type family GhcDiagnosticCode c = n | n -> c where
GhcDiagnosticCode "TcRnBadFamInstDecl" = 06206
GhcDiagnosticCode "TcRnNotOpenFamily" = 06207
GhcDiagnosticCode "TcRnCapturedTermName" = 54201
+ GhcDiagnosticCode "TcRnBindingOfExistingName" = 58805
-- IllegalNewtypeReason
GhcDiagnosticCode "DoesNotHaveSingleField" = 23517
@@ -607,6 +606,8 @@ type family GhcDiagnosticCode c = n | n -> c where
-- no longer reports. These are collected below.
GhcDiagnosticCode "Example outdated error" = 00000
+ GhcDiagnosticCode "TcRnNameByTemplateHaskellQuote" = 40027
+ GhcDiagnosticCode "TcRnIllegalBindingOfBuiltIn" = 69639
{- *********************************************************************
* *
=====================================
hadrian/src/Settings/Builders/RunTest.hs
=====================================
@@ -145,7 +145,7 @@ outOfTreeCompilerArgs = do
withNativeCodeGen <- getBooleanSetting TestGhcWithNativeCodeGen
withInterpreter <- getBooleanSetting TestGhcWithInterpreter
unregisterised <- getBooleanSetting TestGhcUnregisterised
- tables_next_to_code <- getBooleanSetting TestGhcUnregisterised
+ tables_next_to_code <- getBooleanSetting TestGhcTablesNextToCode
targetWithSMP <- targetSupportsSMP
debugAssertions <- getBooleanSetting TestGhcDebugged
=====================================
libraries/base/Data/Kind.hs
=====================================
@@ -1,4 +1,5 @@
-{-# LANGUAGE Trustworthy, ExplicitNamespaces #-}
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE NoImplicitPrelude #-}
-----------------------------------------------------------------------------
-- |
=====================================
libraries/base/Data/Void.hs
=====================================
@@ -1,4 +1,5 @@
{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE NoImplicitPrelude #-}
-----------------------------------------------------------------------------
-- |
=====================================
libraries/base/GHC/Foreign.hs
=====================================
@@ -202,11 +202,11 @@ peekEncodedCString :: TextEncoding -- ^ Encoding of CString
peekEncodedCString (TextEncoding { mkTextDecoder = mk_decoder }) (p, sz_bytes)
= bracket mk_decoder close $ \decoder -> do
let chunk_size = sz_bytes `max` 1 -- Decode buffer chunk size in characters: one iteration only for ASCII
- from0 <- fmap (\fp -> bufferAdd sz_bytes (emptyBuffer fp sz_bytes ReadBuffer)) $ newForeignPtr_ (castPtr p)
- to <- newCharBuffer chunk_size WriteBuffer
+ !from0 <- fmap (\fp -> bufferAdd sz_bytes (emptyBuffer fp sz_bytes ReadBuffer)) $ newForeignPtr_ (castPtr p)
+ !to <- newCharBuffer chunk_size WriteBuffer
- let go !iteration from = do
- (why, from', to') <- encode decoder from to
+ let go !iteration !from = do
+ (why, from', !to') <- encode decoder from to
if isEmptyBuffer from'
then
-- No input remaining: @why@ will be InputUnderflow, but we don't care
@@ -281,11 +281,11 @@ newEncodedCString (TextEncoding { mkTextEncoder = mk_encoder }) null_terminate s
tryFillBuffer :: TextEncoder dstate -> Bool -> Buffer Char -> Ptr Word8 -> Int
-> IO (Maybe (Buffer Word8))
-tryFillBuffer encoder null_terminate from0 to_p to_sz_bytes = do
- to_fp <- newForeignPtr_ to_p
- go (0 :: Int) (from0, emptyBuffer to_fp to_sz_bytes WriteBuffer)
+tryFillBuffer encoder null_terminate from0 to_p !to_sz_bytes = do
+ !to_fp <- newForeignPtr_ to_p
+ go (0 :: Int) from0 (emptyBuffer to_fp to_sz_bytes WriteBuffer)
where
- go !iteration (from, to) = do
+ go !iteration !from !to = do
(why, from', to') <- encode encoder from to
putDebugMsg ("tryFillBufferAndCall: " ++ show iteration ++ " " ++ show why ++ " " ++ summaryBuffer from ++ " " ++ summaryBuffer from')
if isEmptyBuffer from'
@@ -293,8 +293,8 @@ tryFillBuffer encoder null_terminate from0 to_p to_sz_bytes = do
then return Nothing -- We had enough for the string but not the terminator: ask the caller for more buffer
else return (Just to')
else case why of -- We didn't consume all of the input
- InputUnderflow -> recover encoder from' to' >>= go (iteration + 1) -- These conditions are equally bad
- InvalidSequence -> recover encoder from' to' >>= go (iteration + 1) -- since the input was truncated/invalid
+ InputUnderflow -> recover encoder from' to' >>= \(a,b) -> go (iteration + 1) a b -- These conditions are equally bad
+ InvalidSequence -> recover encoder from' to' >>= \(a,b) -> go (iteration + 1) a b -- since the input was truncated/invalid
OutputUnderflow -> return Nothing -- Oops, out of buffer during decoding: ask the caller for more
{-
Note [Check *before* fill in withEncodedCString]
=====================================
libraries/base/changelog.md
=====================================
@@ -1,20 +1,23 @@
# Changelog for [`base` package](http://hackage.haskell.org/package/base)
## 4.18.0.0 *TBA*
- * Add `forall a. Functor (p a)` superclass for `Bifunctor p`.
- * Add Functor instances for `(,,,,) a b c d`, `(,,,,,) a b c d e` and
- `(,,,,,) a b c d e f`.
+ * Add `forall a. Functor (p a)` superclass for `Bifunctor p` ([CLC proposal #91](https://github.com/haskell/core-libraries-committee/issues/91))
+ * Add `Functor` instances for `(,,,,) a b c d`, `(,,,,,) a b c d e` and
+ `(,,,,,) a b c d e f`
* Exceptions thrown by weak pointer finalizers are now reported via a global
exception handler.
- * Add `GHC.Weak.Finalize.{get,set}FinalizerExceptionHandler` which the user to
- override the above-mentioned handler.
- * `Numeric.Natural` re-exports `GHC.Natural.minusNaturalMaybe`.
- * Add `Data.Foldable1` and `Data.Bifoldable1`.
- * Add `applyWhen` to `Data.Function`.
- * Add functions `mapAccumM` and `forAccumM` to `Data.Traversable`, per the
- [Core Libraries proposal](https://github.com/haskell/core-libraries-committee/issues/65).
+ * Add `GHC.Weak.Finalize.{get,set}FinalizerExceptionHandler` which allows the
+ user to override the above-mentioned handler.
+ * `Numeric.Natural` re-exports `GHC.Natural.minusNaturalMaybe`
+ ([CLC proposal #45](https://github.com/haskell/core-libraries-committee/issues/45))
+ * Add `Data.Foldable1` and `Data.Bifoldable1`
+ ([CLC proposal #9](https://github.com/haskell/core-libraries-committee/issues/9))
+ * Add `applyWhen` to `Data.Function`
+ ([CLC proposal #71](https://github.com/haskell/core-libraries-committee/issues/71))
+ * Add functions `mapAccumM` and `forAccumM` to `Data.Traversable`
+ ([CLC proposal #65](https://github.com/haskell/core-libraries-committee/issues/65))
* Add default implementation of `(<>)` in terms of `sconcat` and `mempty` in
- terms of `mconcat`.
+ terms of `mconcat` ([CLC proposal #61](https://github.com/haskell/core-libraries-committee/issues/61)).
* `GHC.Conc.Sync.listThreads` was added, allowing the user to list the threads
(both running and blocked) of the program.
* `GHC.Conc.Sync.labelThreadByteArray#` was added, allowing the user to specify
@@ -23,25 +26,24 @@
function.
* `GHC.Conc.Sync.threadLabel` was added, allowing the user to query the label
of a given `ThreadId`.
- * Add `inits1` and `tails1` to `Data.List.NonEmpty`.
+ * Add `inits1` and `tails1` to `Data.List.NonEmpty`
+ ([CLC proposal #67](https://github.com/haskell/core-libraries-committee/issues/67))
* Change default `Ord` implementation of `(>=)`, `(>)`, and `(<)` to use
- `(<=)` instead of `compare` per
- [Core Libraries proposal](https://github.com/haskell/core-libraries-committee/issues/24).
+ `(<=)` instead of `compare` ([CLC proposal #24](https://github.com/haskell/core-libraries-committee/issues/24)).
* Export `liftA2` from `Prelude`. This means that the entirety of `Applicative`
- is now exported from `Prelude`. See [CLC #50](https://github.com/haskell/core-libraries-committee/issues/50)
- for the related discussion,
- as well as [the migration guide](https://github.com/haskell/core-libraries-committee/blob/main/guides/export-lifta2-prelude.md)
+ is now exported from `Prelude`
+ ([CLC proposal #50](https://github.com/haskell/core-libraries-committee/issues/50),
+ [the migration
+ guide](https://github.com/haskell/core-libraries-committee/blob/main/guides/export-lifta2-prelude.md))
* Update to [Unicode 15.0.0](https://www.unicode.org/versions/Unicode15.0.0/).
* Add standard Unicode case predicates `isUpperCase` and `isLowerCase` to
`GHC.Unicode` and `Data.Char`. These predicates use the standard Unicode
- case properties and are more intuitive than `isUpper` and `isLower`. See
- [CLC proposal #90](https://github.com/haskell/core-libraries-committee/issues/90).
+ case properties and are more intuitive than `isUpper` and `isLower`
+ ([CLC proposal #90](https://github.com/haskell/core-libraries-committee/issues/90))
* Add `Eq` and `Ord` instances for `Generically1`.
* Relax instances for Functor combinators; put superclass on Class1 and Class2
- to make non-breaking. See [CLC
- #10](https://github.com/haskell/core-libraries-committee/issues/10) for the
- related discussion, as well as [the migration
- guide](https://github.com/haskell/core-libraries-committee/blob/main/guides/functor-combinator-instances-and-class1s.md).
+ to make non-breaking ([CLC proposal #10](https://github.com/haskell/core-libraries-committee/issues/10),
+ [migration guide](https://github.com/haskell/core-libraries-committee/blob/main/guides/functor-combinator-instances-and-class1s.md))
* Add `gcdetails_block_fragmentation_bytes` to `GHC.Stats.GCDetails` to track heap fragmentation.
* `GHC.TypeLits` and `GHC.TypeNats` now export the `natSing`, `symbolSing`,
and `charSing` methods of `KnownNat`, `KnownSymbol`, and `KnownChar`,
@@ -50,16 +52,16 @@
types, per
[CLC proposal #85](https://github.com/haskell/core-libraries-committee/issues/85).
* The `Enum` instance of `Down a` now enumerates values in the opposite
- order as the `Enum a` instance, per
- [CLC proposal #51](https://github.com/haskell/core-libraries-committee/issues/51).
+ order as the `Enum a` instance ([CLC proposal #51](https://github.com/haskell/core-libraries-committee/issues/51))
* `Foreign.Marshal.Pool` now uses the RTS internal arena instead of libc
`malloc` for allocation. It avoids the O(n) overhead of maintaining a list
of individually allocated pointers as well as freeing each one of them when
- freeing a `Pool`. (#14762) (#18338)
+ freeing a `Pool` (#14762, #18338)
* `Type.Reflection.Unsafe` is now marked as unsafe.
- * Add `Data.Typeable.heqT`, a kind-heterogeneous version of `Data.Typeable.eqT`.
- * Add `Data.List.!?` per
- [CLC proposal #110](https://github.com/haskell/core-libraries-committee/issues/110).
+ * Add `Data.Typeable.heqT`, a kind-heterogeneous version of
+ `Data.Typeable.eqT`
+ ([CLC proposal #99](https://github.com/haskell/core-libraries-committee/issues/99))
+ * Add `Data.List.!?` ([CLC proposal #110](https://github.com/haskell/core-libraries-committee/issues/110))
* `maximumBy`/`minimumBy` are now marked as `INLINE` improving performance for unpackable
types significantly.
=====================================
rts/include/Rts.h
=====================================
@@ -167,7 +167,10 @@ void _warnFail(const char *filename, unsigned int linenum);
#endif /* DEBUG */
#if __STDC_VERSION__ >= 201112L
-#define GHC_STATIC_ASSERT(x, msg) static_assert((x), msg)
+// `_Static_assert` is provided by C11 but is deprecated and replaced by
+// `static_assert` in C23. Perhaps some day we should instead use the latter.
+// See #22777.
+#define GHC_STATIC_ASSERT(x, msg) _Static_assert((x), msg)
#else
#define GHC_STATIC_ASSERT(x, msg)
#endif
=====================================
testsuite/tests/rename/should_fail/T14907b.stderr
=====================================
@@ -1,9 +1,9 @@
-T14907b.hs:5:1: error: [GHC-69639]
- Illegal binding of built-in syntax: ()
+T14907b.hs:5:1: error: [GHC-58805]
+ Illegal binding of an existing name: ()
-T14907b.hs:6:1: error: [GHC-69639]
- Illegal binding of built-in syntax: (,)
+T14907b.hs:6:1: error: [GHC-58805]
+ Illegal binding of an existing name: (,)
-T14907b.hs:7:1: error: [GHC-69639]
- Illegal binding of built-in syntax: (,,)
+T14907b.hs:7:1: error: [GHC-58805]
+ Illegal binding of an existing name: (,,)
=====================================
testsuite/tests/rename/should_fail/T22839.hs
=====================================
@@ -0,0 +1,5 @@
+module T22839 where
+
+data []
+
+data (->)
=====================================
testsuite/tests/rename/should_fail/T22839.stderr
=====================================
@@ -0,0 +1,6 @@
+
+T22839.hs:3:1: error: [GHC-58805]
+ Illegal binding of an existing name: []
+
+T22839.hs:5:1: error: [GHC-58805]
+ Illegal binding of an existing name: ->
=====================================
testsuite/tests/rename/should_fail/all.T
=====================================
@@ -183,3 +183,4 @@ test('T21605a', normal, compile_fail, [''])
test('T21605b', normal, compile_fail, [''])
test('T21605c', normal, compile_fail, [''])
test('T21605d', normal, compile_fail, [''])
+test('T22839', normal, compile_fail, [''])
=====================================
testsuite/tests/rename/should_fail/rnfail042.stderr
=====================================
@@ -1,12 +1,12 @@
-rnfail042.hs:5:11: error: [GHC-69639]
- Illegal binding of built-in syntax: ()
+rnfail042.hs:5:11: error: [GHC-58805]
+ Illegal binding of an existing name: ()
-rnfail042.hs:6:10: error: [GHC-69639]
- Illegal binding of built-in syntax: (,,,)
+rnfail042.hs:6:10: error: [GHC-58805]
+ Illegal binding of an existing name: (,,,)
-rnfail042.hs:7:12: error: [GHC-69639]
- Illegal binding of built-in syntax: []
+rnfail042.hs:7:12: error: [GHC-58805]
+ Illegal binding of an existing name: []
-rnfail042.hs:8:13: error: [GHC-69639]
- Illegal binding of built-in syntax: :
+rnfail042.hs:8:13: error: [GHC-58805]
+ Illegal binding of an existing name: :
=====================================
testsuite/tests/th/T13968.stderr
=====================================
@@ -1,3 +1,3 @@
-T13968.hs:6:2: error: [GHC-40027]
- Cannot redefine a Name retrieved by a Template Haskell quote: succ
+T13968.hs:6:2: error: [GHC-58805]
+ Illegal binding of an existing name: succ
=====================================
testsuite/tests/typecheck/should_compile/T22519.hs
=====================================
@@ -0,0 +1,21 @@
+{-# LANGUAGE Haskell2010 #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
+module Bug where
+
+import Data.Coerce (coerce)
+import Data.Kind (Type)
+import GHC.TypeNats (Nat, type (<=))
+
+f :: (1 <= w)
+ => IO (SymBV' sym w)
+ -> IO (SymBV sym w)
+f = coerce
+
+----
+
+data BaseType = BaseBVType Nat
+type family SymExpr (sym :: Type) :: BaseType -> Type
+type SymBV sym n = SymExpr sym (BaseBVType n)
+newtype SymBV' sym w = MkSymBV' (SymBV sym w)
=====================================
testsuite/tests/typecheck/should_compile/all.T
=====================================
@@ -457,6 +457,7 @@ test('T10335', normal, compile, [''])
test('Improvement', normal, compile, [''])
test('T10009', normal, compile, [''])
test('T10390', normal, compile, [''])
+test('T22519', normal, compile, [''])
test('T8555', normal, compile, [''])
test('T8799', normal, compile, [''])
test('T10432', normal, compile, [''])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2ee2bad566665877d69af4cef02b25a77c561287...26b820e5150e87b245816b50385e148bdccbb82b
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/2ee2bad566665877d69af4cef02b25a77c561287...26b820e5150e87b245816b50385e148bdccbb82b
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