GHC hangs during type-checking
GHC 8.0.2 doesn't terminate when type checking this file:
import Control.Lens
import Data.Functor.Compose
traverseCompose :: (a -> f b) -> g a -> f (h _)
traverseCompose = _Wrapping Compose . traverseThis is the smallest type signature I could find that still causes the problem. GHCi infers the type without issue, and when I annotate it with the correct type signature, the file is successfully compiled.
Using base-4.9.1.0, lens-4.14.1, and transformers-0.5.2.0
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.0.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
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| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |