| typecheck/should_fail/T7368) Solution: track the provenance of | Derived constraints and refuse to float out a constraint that has | an insoluble Derived. For the record, that's not the solution that the patch implements. Instead we just don’t float heterogeneous equalities. I think Richard just forgot to update the commit message. Simon | -----Original Message----- | From: ghc-commits [mailto:ghc-commits-bounces@haskell.org] On Behalf | Of git@git.haskell.org | Sent: 27 July 2017 12:50 | To: ghc-commits@haskell.org | Subject: [commit: ghc] master: Improve error messages around kind | mismatches. (8e15e3d) | | Repository : ssh://git@git.haskell.org/ghc | | On branch : master | Link : | https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fghc.ha | skell.org%2Ftrac%2Fghc%2Fchangeset%2F8e15e3d370e9c253ae0dbb330e25b72cb | 00cdb76%2Fghc&data=02%7C01%7Csimonpj%40microsoft.com%7C9993301a429e467 | e29b008d4d4e6350f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6363675 | 32584262688&sdata=bY%2Bruj0hhXfC23hfMA1ivuAs2Av2%2BY4%2BJK2yyCoPzbA%3D | &reserved=0 | | >--------------------------------------------------------------- | | commit 8e15e3d370e9c253ae0dbb330e25b72cb00cdb76 | Author: Richard Eisenberg | Date: Thu Jun 1 17:27:14 2017 -0400 | | Improve error messages around kind mismatches. | | Previously, when canonicalizing (or unifying, in uType) a | heterogeneous equality, we emitted a kind equality and used the | resulting coercion to cast one side of the heterogeneous equality. | | While sound, this led to terrible error messages. (See the bugs | listed below.) The problem is that using the coercion built from | the emitted kind equality is a bit like a wanted rewriting a | wanted. | The solution is to keep heterogeneous equalities as irreducible. | | See Note [Equalities with incompatible kinds] in TcCanonical. | | This commit also removes a highly suspicious switch to | FM_SubstOnly | when flattening in the kinds of a type variable. I have no idea | why this was there, other than as a holdover from pre-TypeInType. | I've not left a Note because there is simply no reason I can | conceive | of that the FM_SubstOnly should be there. | | One challenge with this patch is that the emitted derived | equalities | might get emitted several times: when a heterogeneous equality is | in an implication and then gets floated out from the implication, | the Derived is present both in and out of the implication. This | causes a duplicate error message. (Test case: | typecheck/should_fail/T7368) Solution: track the provenance of | Derived constraints and refuse to float out a constraint that has | an insoluble Derived. | | Lastly, this labels one test (dependent/should_fail/RAE_T32a) | as expect_broken, because the problem is really #12919. The | different handling of constraints in this patch exposes the error. | | This fixes bugs #11198, #12373, #13530, and #13610. | | test cases: | typecheck/should_fail/{T8262,T8603,tcail122,T12373,T13530,T13610} | | | >--------------------------------------------------------------- | | 8e15e3d370e9c253ae0dbb330e25b72cb00cdb76 | compiler/typecheck/TcCanonical.hs | 296 | ++++++++++++--------- | compiler/typecheck/TcErrors.hs | 75 ++++-- | compiler/typecheck/TcEvidence.hs | 8 +- | compiler/typecheck/TcFlatten.hs | 31 ++- | compiler/typecheck/TcRnTypes.hs | 30 ++- | compiler/typecheck/TcSimplify.hs | 34 ++- | compiler/typecheck/TcType.hs | 10 +- | compiler/typecheck/TcUnify.hs | 28 +- | compiler/types/Type.hs | 4 +- | testsuite/tests/dependent/should_fail/T11471.hs | 2 +- | .../tests/dependent/should_fail/T11471.stderr | 11 +- | testsuite/tests/dependent/should_fail/all.T | 2 +- | testsuite/tests/gadt/gadt7.stderr | 6 +- | .../tests/ghci.debugger/scripts/break012.stdout | 14 +- | .../indexed-types/should_fail/ExtraTcsUntch.stderr | 6 +- | .../tests/indexed-types/should_fail/T5934.stderr | 13 - | testsuite/tests/polykinds/T12593.stderr | 56 ++++ | testsuite/tests/polykinds/T13555.stderr | 21 +- | testsuite/tests/polykinds/T7438.stderr | 6 +- | testsuite/tests/polykinds/T8566.stderr | 2 +- | testsuite/tests/polykinds/T9017.stderr | 10 +- | testsuite/tests/typecheck/should_fail/T12373.hs | 10 + | .../tests/typecheck/should_fail/T12373.stderr | 8 + | testsuite/tests/typecheck/should_fail/T13530.hs | 11 + | .../tests/typecheck/should_fail/T13530.stderr | 7 + | testsuite/tests/typecheck/should_fail/T13610.hs | 11 + | .../tests/typecheck/should_fail/T13610.stderr | 14 + | testsuite/tests/typecheck/should_fail/T5691.stderr | 10 +- | testsuite/tests/typecheck/should_fail/T7368.stderr | 6 +- | .../tests/typecheck/should_fail/T7368a.stderr | 2 +- | testsuite/tests/typecheck/should_fail/T7453.stderr | 48 +--- | testsuite/tests/typecheck/should_fail/T7696.stderr | 4 +- | testsuite/tests/typecheck/should_fail/T8262.stderr | 6 +- | testsuite/tests/typecheck/should_fail/T8603.hs | 4 + | testsuite/tests/typecheck/should_fail/T8603.stderr | 13 +- | testsuite/tests/typecheck/should_fail/all.T | 3 + | .../tests/typecheck/should_fail/tcfail090.stderr | 4 +- | .../tests/typecheck/should_fail/tcfail122.stderr | 8 +- | .../tests/typecheck/should_fail/tcfail123.stderr | 13 +- | .../tests/typecheck/should_fail/tcfail200.stderr | 6 +- | 40 files changed, 537 insertions(+), 316 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 | 8e15e3d370e9c253ae0dbb330e25b72cb00cdb76 | _______________________________________________ | ghc-commits mailing list | ghc-commits@haskell.org | https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.h | askell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc- | commits&data=02%7C01%7Csimonpj%40microsoft.com%7C9993301a429e467e29b00 | 8d4d4e6350f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6363675325842 | 62688&sdata=JkrPJNfzdjx2Rz%2FfcMq2HlIP%2BlsFIE%2FT68a%2FSUae%2Fzo%3D&r | eserved=0