#11712: Very confusing error message with -fprint-explicit-kinds -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler (Type | Version: 7.10.3 checker) | Resolution: | Keywords: 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 goldfire): The reason for the inconsistency is because, without `-fprint-equality- relations`, all of `(~)`, `(~~)`, and `(~#)` render as `(~)`. In a program that doesn't mention equality (or mentions only `(~)`), any of these may appear. In order not to scare users with three equality relations, I taught GHC to print just one. But I'm very uncertain about this decision. I asked on devs a while ago, and the best suggestion there was to render the heterogeneous ones as heterogeneous when, in fact, the kinds on their sides differ -- but only then. Perhaps I'll implement that alongside the other suggestion here. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11712#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler