reify never provides the declaration of variables
The information returned by reify when provided a variable Name is
VarI Name Type (Maybe Dec) FixityThe Dec part, due to be nested in Maybe, is clearly optional. In fact, according to Language.Haskell.TH.Syntax:
-- Nothing for lambda-bound variables, and
-- for anything else TH can't figure out
-- E.g. [| let x = 1 in $(do { d <- reify 'x; .. }) |]However, the typechecker (TcSplice module) always returns Nothing. So it's simply not implemented.
I suggest either implementing the feature or removing the Dec part of VarI. Either way, the type should be consistent with the features offered in TH.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.8.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Template Haskell |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | Unknown |
| Architecture | Unknown |