#8707: Kind inference fails in data instance definition -------------------------------------+------------------------------------ Reporter: goldfire | Owner: jstolarek Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by simonpj): I'm not sure of the problem here. It's true that, even with `-fprint- explicit-kinds` a promoted tuple data constructor is printed without its kind arguments, hence {{{ Data constructor ‛SFalse’ returns type ‛SingDF Bool k '('False, Ctor k)’ }}} Is that bad? When we pretty-print Core we print tuple terms without the type args, thus {{{ ('x', True) rather than (,) Char Bool 'x' True }}} Richard, re (2) why do you say that the error message is unhelpful compared to 7.6? Jan, how did you manage to get GHC to produce this? {{{ Data constructor `SFalse' returns type `SingDF Bool k ('(,) Bool (k -> *) 'False (Ctor k))' }}} That does look wrong. Can you explain how to reproduce it? Point (1) is another matter. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8707#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler