Incorrect imported module not used warning
A test case, with 3 files in.
-- AAA.hs
module AAA where
data Foo = Foo
-- AA.hs
module AA(Foo) where
import AAA
-- A.hs
module A where
import qualified AA
import AAA
type Bar = AA.Foo
Trying it out gives:
$ ghc --make
[3 of 3] Compiling A ( A.hs, A.o )
A.hs:2:0:
Warning: Module `AA' is imported, but nothing from it is used,
except perhaps instances visible in `AA'
To suppress this warning, use: import AA()
Foo
comes from AAA
, but is used with the import from AA
, so it should be saying {{{AAA} is imported but not used. It seems the import warnings are based on final fully resolved names, but this doesn't deal with re-exports or qualification correctly.
I came accross this test case while tracking down a much more complex example which gave a case where an unqualified module was reported as being redundant - despite the fact that it was required - so it seems there are several bugs around this area.
Trac metadata
Trac field | Value |
---|---|
Version | 6.9 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |