#12694: GHC HEAD no longer reports inaccessible code -------------------------------------+------------------------------------- Reporter: ezyang | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.1 checker) | Keywords: Resolution: | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #12466, #11066, | Differential Rev(s): #13766 | Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): It seems that GHC 8.2 and later report this as inaccessible code again: {{{ $ /opt/ghc/8.4.3/bin/ghc Bug.hs [1 of 1] Compiling A ( Bug.hs, Bug.o ) Bug.hs:4:7: error: • Could not deduce: a ~ b from the context: Bool ~ Int bound by the type signature for: f :: forall a b. (Bool ~ Int) => a -> b at Bug.hs:3:1-25 ‘a’ is a rigid type variable bound by the type signature for: f :: forall a b. (Bool ~ Int) => a -> b at Bug.hs:3:1-25 ‘b’ is a rigid type variable bound by the type signature for: f :: forall a b. (Bool ~ Int) => a -> b at Bug.hs:3:1-25 • In the expression: x In an equation for ‘f’: f x = x • Relevant bindings include x :: a (bound at Bug.hs:4:3) f :: a -> b (bound at Bug.hs:4:1) | 4 | f x = x | ^ }}} Perhaps this can be closed, then? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12694#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler