#9173: Better type error messages -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: | TypeErrorMessages 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 j.waldmann): Interesting, but I think this is a separate issue (type error message for list literals). `['a', True]` gets translated to `'a' : (True : [])`, see language spec 3.7. https://www.haskell.org/onlinereport/haskell2010/haskellch3.html#x8-340003.7 So there is no special rule for typing list literals, as the compiler checks the translated code anyway. Or so I thought, but in fact there is: after stating the translation, the standard states that in `[e1, ..., ek]`, "the types of e1 ... ek must all be the same". Is this normative, or just a (redundant) explanation? I do think that compiler (error) messages should use wording from the standard. (So, looking up words in OED does not really help. The committee that wrote the standard already did this.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9173#comment:28 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler