#15899: Testcase tcfail158 is broken -------------------------------------+------------------------------------- Reporter: RolandSenn | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Test Suite | Version: 8.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: | Blocking: Related Tickets: #12906 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Here is a somewhat simplified version of the issue: {{{#!hs module Bug where f, g :: Maybe f = Nothing g = undefined }}} In GHC 8.6.2, this simply errors with: {{{ $ ~/Software/haskell/ghc-8.6.2/bin/ghc Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:3:9: error: • Expecting one more argument to ‘Maybe’ Expected a type, but ‘Maybe’ has kind ‘* -> *’ • In the type signature: f :: Maybe | 3 | f, g :: Maybe | ^^^^^ }}} But in GHC HEAD (as of commit df570d920fa66db631f936fa377e598fe92bd2a1), we get many more errors: {{{ $ ghc/inplace/bin/ghc-stage2 Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:3:9: error: • Expecting one more argument to ‘Maybe’ Expected a type, but ‘Maybe’ has kind ‘* -> *’ • In the type signature: f :: Maybe | 3 | f, g :: Maybe | ^^^^^ Bug.hs:4:5: error: • Couldn't match expected type ‘Maybe’ with actual type ‘Maybe a1’ • In the expression: Nothing In an equation for ‘f’: f = Nothing | 4 | f = Nothing | ^^^^^^^ Bug.hs:5:5: error: • Couldn't match kind ‘* -> *’ with ‘*’ When matching types a0 :: * Maybe :: * -> * • In the expression: undefined In an equation for ‘g’: g = undefined | 5 | g = undefined | ^^^^^^^^^ }}} I'll try tracking down which commit introduced this regression when I get a chance. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15899#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler