Type roles in GHCi
This works:
λ> data A a; type role A nominal
λ> :i A
type role A nominal
data A a
This doesn't:
λ> data A a
λ> type role A nominal
λ> :i A
type role A phantom
data A a
Accepting role annotations after the definition probably leads to problems when intermediate definitions relied on the earlier role; so I think the second situation should give an error. In fact, in the second snippet GHC does not even require -XRoleAnnotations.
Trac metadata
Trac field | Value |
---|---|
Version | 7.7 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | goldfire |
Operating system | |
Architecture |