[GHC] #9803: Poor error message for unbound variable in pattern synonym
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: hour) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- When I say {{{ pattern OneElt = [x] }}} I get {{{ Right-hand side of bidirectional pattern synonym cannot be used as an expression [x] }}} I have two complaints with this error message: 1. It's very unclear what's actually wrong with the pattern -- `[x]` looks like a perfectly fine expression, until I realize that `x` is unbound. 2. The herald of the error is more than 80 characters (if you count the indentation) and wraps on my 80-character terminal. GHC tends to avoid this elsewhere, and so the wrapping is suboptimal. I would easily say that issue (1) is more important than issue (2). Perhaps this would be better: {{{ Variable `x' is unbound in the bidirectional pattern synonym `OneElt': [x] }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.9 checker) | Keywords: Resolution: | Architecture: Operating System: Unknown/Multiple | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #8841 | Differential Revisions: -------------------------------------+------------------------------------- Changes (by thomie): * cc: cactus (added) * component: Compiler => Compiler (Type checker) * related: => #8841 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.9 checker) | Keywords: Resolution: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by thomie): * keywords: => PatternSynonyms * failure: None/Unknown => Incorrect warning at compile-time * cc: cactus (removed) * cc: mpickering (added) * related: #8841 => -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: mpickering Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.9 checker) | Keywords: Resolution: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * owner: => mpickering Comment: I will do this. I should wait for Simon to finish on #11224. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: mpickering Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.9 checker) | Keywords: Resolution: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): OK Matthew, you're all set to look at this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#9803: Poor error message for unbound variable in pattern synonym -------------------------------------+------------------------------------- Reporter: goldfire | Owner: mpickering Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler (Type | Version: 7.9 checker) | Keywords: Resolution: fixed | PatternSynonyms Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * status: new => closed * resolution: => fixed Comment: Simon got to this whilst doing some other cleanup. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9803#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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