#16137: unhelpful parse error message: Unexpected do block in function application -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Not a bug, as ghc correctly rejects an invalid program. But I have the impression that the error message is getting less precise (for reason and location) from 8.4 to 8.6: {{{ foo = do let x = case y of Nothing -> True bar }}} 8.6.3 says {{{ P.hs:1:7: error: Unexpected do block in function application: do let x = ... You could write it with parentheses Or perhaps you meant to enable BlockArguments? | 1 | foo = do | ^^... }}} I am not seeing what application ghc thinks of. 8.4.4 had the more useful {{{ P.hs:3:5: error: parse error on input ‘Nothing’ | 3 | Nothing -> True | ^^^^^^^ }}} More useful, since in the actual code, from which I distilled the above, there were a dozen lines between the locations that were reported by 8.6.3 and 8.4.4. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16137 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler