#15458: Misleading error message on mising BangPatterns extension -------------------------------------+------------------------------------- Reporter: sergv | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Poor/confusing (amd64) | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- For following program I'm getting an unexpected error message. {{{#!hs foo :: Int -> Int foo = bar where bar :: Int -> Int bar !i = i }}} {{{ $ ghc -o Test Test.hs [1 of 1] Compiling Main ( Test.hs, Test.o ) Test.hs:4:5: error: The type signature for ‘bar’ lacks an accompanying binding | 4 | bar :: Int -> Int | ^^^ }}} Enabling `-XBangPatterns` fixes the issue but I wanted the compiler to suggest me to enable it: {{{ $ ghc -XBangPatterns -o Test Test.hs [1 of 1] Compiling Main ( Test.hs, Test.o ) Test.hs:1:1: error: The IO action ‘main’ is not defined in module ‘Main’ | 1 | foo :: Int -> Int | ^ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15458 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler