[GHC] #14045: Data family instances must list all patterns of family, despite documentation's claims to the contrary
GHC
ghc-devs at haskell.org
Mon Jul 31 12:34:12 UTC 2017
#14045: Data family instances must list all patterns of family, despite
documentation's claims to the contrary
-------------------------------------+-------------------------------------
Reporter: RyanGlScott | Owner: (none)
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler (Type | Version: 8.3
checker) |
Resolution: | Keywords: TypeFamilies
Operating System: Unknown/Multiple | Architecture:
| Unknown/Multiple
Type of failure: GHC rejects | Test Case: indexed-
valid program | types/should_compile/T14045,
| indexed-types/should_fail/T14045a
Blocked By: | Blocking:
Related Tickets: #12369 | Differential Rev(s): Phab:D3804
Wiki Page: |
-------------------------------------+-------------------------------------
Comment (by goldfire):
Does that do it? It's all in `Note [Arity of data families]` in
FamInstEnv.
Also, the skipped arity check in the previous patch is in `tc_fam_ty_pats`
in TcTyClsDecls.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14045#comment:10>
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