Template Haskell cannot represent type wildcards
There does not appear to be a way for Template Haskell code to generate partial type signature wildcards. The type quasiquote [t|_|] results in Wildcard not allowed, and use in an expression quasiquote like [|() :: _|] results in Exotic form of type not (yet) handled by Template Haskell _.
It would be useful if TH code could partially constrain the type of the expressions it was generating, without needing to determine the type completely.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.10.1-rc1 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Template Haskell |
| Test case | |
| Differential revisions | |
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