Standalone deriving using template haskell
Currently, there seems to be no support for standalone deriving in TemplateHaskell:
Prelude Data.Typeable Language.Haskell.TH> :set -XStandaloneDeriving
Prelude Data.Typeable Language.Haskell.TH> data Weird a (b :: * -> * -> *) c = Weird
Prelude Data.Typeable Language.Haskell.TH> runQ $ [d| deriving instance Typeable Weird |]
[]Use case:
The library typeable-th can already generate Typeable instances using TH for GHC 7.4 and 7.6. To add support for GHC 7.8 in a way that the user doesn't have to care about the version, there has to be a way to make Typeable instances via TH in GHC 7.8. This is currently impossible, but with StandaloneDeriving support for TH, it would be possible.
Trac metadata
| Trac field | Value |
|---|---|
| Version | |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Template Haskell |
| Test case | |
| Differential revisions | |
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