Spurious type variable scope error report
A spurious error message about a variable being out of scope can be triggered by a kind error. The kind error and scope error need not occur in the same function.
This code reproduces the error:
data Val v sm = Val
foo :: forall v sm. Val v sm
foo = undefined
where foo1 :: Val v sm
foo1 = bar
-- Correct type signature: bar :: forall v sm. Val v sm
bar :: forall v. Val v
bar = undefined fooThe reported error looks like this:
GHC internal error: `v' is not in scope
In the type signature: foo1 :: Val v sm
In the definition of `foo':
foo = undefined
where
foo1 :: Val v sm
foo1 = barA kind error is also reported for the type signature of bar.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.4.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |