#14265: kinded holes -------------------------------------+------------------------------------- Reporter: lspitzner | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.2.1 checker) | Keywords: Resolution: | PartialTypeSignatures Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * keywords: => PartialTypeSignatures * component: Compiler => Compiler (Type checker) Comment: You didn't give a concrete example of what you'd like to see, so I'm forced to guess. My shot-in-the-dark attempt is this program: {{{#!hs {-# LANGUAGE PolyKinds #-} f :: proxy _ -> () f _ = () }}} {{{ GHCi, version 8.2.1: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Main ( Bug.hs, interpreted ) Bug.hs:3:12: error: • Found type wildcard ‘_’ standing for ‘w’ Where: ‘w’ is a rigid type variable bound by the inferred type of f :: proxy w -> () at Bug.hs:4:1-8 ‘k’ is a rigid type variable bound by the inferred type of f :: proxy w -> () at Bug.hs:4:1-8 To use the inferred type, enable PartialTypeSignatures • In the type signature: f :: proxy _ -> () | 3 | f :: proxy _ -> () | ^ }}} This output is indeed pretty skeevy-looking¸ since it points out a kind variable `k` in a `Where:` clause, but `k` isn't used anywhere else! Perhaps you wanted to see something like this instead? {{{ • Found type wildcard ‘_’ standing for ‘w’ (of kind ‘k’) Where: ... }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14265#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler