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| author | sheaf <sam.derbyshire@gmail.com> | 2021-10-06 18:22:28 +0200 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-10-09 04:46:05 -0400 |
| commit | 31983ab4c65204ad0fd14aac4c00648f5fa6ad6b (patch) | |
| tree | 6bff70ce40f4d295ce084358ebe4b977e68bb43f /testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr | |
| parent | a76409c758d8c7bd837dcc6c0b58f8cce656b4f1 (diff) | |
| download | haskell-31983ab4c65204ad0fd14aac4c00648f5fa6ad6b.tar.gz | |
Reject GADT pattern matches in arrow notation
Tickets #20469 and #20470 showed that the current
implementation of arrows is not at all up to the task
of supporting GADTs: GHC produces ill-scoped Core programs
because it doesn't propagate the evidence introduced by a GADT
pattern match.
For the time being, we reject GADT pattern matches in arrow notation.
Hopefully we are able to add proper support for GADTs in arrows
in the future.
Diffstat (limited to 'testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr')
| -rw-r--r-- | testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr b/testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr new file mode 100644 index 0000000000..0241dc9739 --- /dev/null +++ b/testsuite/tests/arrows/gadt/ArrowGADTKappa.stderr @@ -0,0 +1,6 @@ + +ArrowGADTKappa.hs:17:26: error: + • Proc patterns cannot use existential or GADT data constructors + • In the pattern: MkG g + In an arrow kappa abstraction: (MkG g) -> show -< g + In the command: (id -< x) `handleG` (MkG g) -> show -< g |