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 foo

The 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 = bar

A 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)
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