Confused type checker with typed holes and a missing instance (also panic)
If your file contains a typed hole and a case where an instance is missing, the type checker will not find the missing instance and only report the hole. If -fdefer-typed-holes is set, this results in a panic. (Using ghci, the panic occurs when any definition of the module is being evaluated)
Minimal working example:
{-# OPTIONS_GHC -fdefer-typed-holes #-}
data Asd = Asd
someHole = _asd
missingInstance :: Asd -> Asd -> Bool
missingInstance x y = x == y
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.10.3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |