Re: [GHC] #10890: Incorrect redundant import warning for type classes

#10890: Incorrect redundant import warning for type classes -------------------------------------+------------------------------------- Reporter: quchen | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | warnings/should_compile/T10890, | T10890_1, T10890_2 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1257 Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * testcase: => warnings/should_compile/T10890, T10890_1, T10890_2 Comment: I followed up with this {{{ commit 3e94842d4d1258fbd6a1202bf74d41ce1d01c753 Author: Simon Peyton Jones Date: Fri Oct 30 09:41:47 2015 +0000 Record usage information using GlobalRdrElt This patch implements an improvment that I've wanted to do for ages, but never gotten around to. Unused imports are computed based on how imported entities occur (qualified, unqualified). This info was accumulated in tcg_used_rdrnames :: Set RdrName. But that was a huge pain, and it got worse when we introduced duplicate record fields. The Right Thing is to record tcg_used_gres :: [GlobalRdrElt], which records the GRE *after* filtering with pickGREs. See Note [GRE filtering] in RdrName. This is much, much bette. This patch deletes quite a bit of code, and is conceptually much easier to follow. Hooray. There should be no change in functionality. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10890#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler