#8264: Canonical way to prevent manual instances --------------------------------------------+------------------------------ Reporter: nomeata | Owner: Type: task | Status: closed Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.6.3 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Changes (by nomeata): * status: new => closed * resolution: => fixed Comment: This was introduced in 17a868afa169c52d8525a95cbed87b2fc12044c6, (`abstractClasses`, used in `checkValidInstHead`) for `Coercible` only so far. This position is, however, unsuitable for classes that are being derived, as these also have to pass through `checkValidInstHead`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8264#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler