#3371: Spurious "Defined but not used" when using record wildcards
--------------------------------------------+-------------------------------
Reporter: Baughn | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 6.10.3
Severity: minor | Resolution: fixed
Keywords: | Difficulty: Unknown
Testcase: rename/should_compile/T3371 | Os: Unknown/Multiple
Architecture: Unknown/Multiple |
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Changes (by simonpj):
* testcase: => rename/should_compile/T3371
* difficulty: => Unknown
* status: new => closed
* resolution: => fixed
Comment:
Good point. I fixed this, and some related stuff concerning named fields,
with this patch:
{{{
Thu Aug 20 13:34:43 BST 2009 [email protected]
* Improvements to record puns, wildcards
* Make C { A.a } work with punning, expanding to C { A.a = a }
* Make it so that, with -fwarn-unused-matches,
f (C {..}) = x
does not complain about the bindings introduced by the "..".
* Make -XRecordWildCards implies -XDisambiguateRecordFields.
* Overall refactoring of RnPat, which had become very crufty.
In particular, there is now a monad, CpsRn, private to RnPat,
which deals with the cps-style plumbing. This is why so many
lines of RnPat have changed.
* Refactor the treatment of renaming of record fields into two passes
- rnHsRecFields1, used both for patterns and expressions,
which expands puns, wild-cards
- a local renamer in RnPat for fields in patterns
- a local renamer in RnExpr for fields in construction and update
This make it all MUCH easier to understand
* Improve documentation of record puns, wildcards, and disambiguation
M ./compiler/basicTypes/RdrName.lhs -5 +9
M ./compiler/main/DynFlags.hs +6
M ./compiler/parser/RdrHsSyn.lhs -11 +4
M ./compiler/rename/RnBinds.lhs -6 +7
M ./compiler/rename/RnEnv.lhs -139 +124
M ./compiler/rename/RnExpr.lhs -6 +27
M ./compiler/rename/RnPat.lhs -384 +394
M ./compiler/rename/RnSource.lhs -5 +4
M ./compiler/rename/RnTypes.lhs -2 +2
M ./compiler/typecheck/TcEnv.lhs -2 +2
M ./compiler/typecheck/TcPat.lhs -1 +1
M ./docs/users_guide/glasgow_exts.xml -22 +92
}}}
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3371#comment:1>
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