#10347: Spurious "unused constructor" warning with Coercible -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 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 Revisions: -------------------------------------+------------------------------------- Comment (by goldfire): Good point. Here's a revised test case: {{{ module T10347 (N, mkN) where import Data.Coerce newtype N a = MkN Int mkN :: Int -> N a mkN = coerce }}} Now you ''can'' make an `N a`, but the warning still appears. This is actually much simpler than the original test case. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10347#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler