id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
4047	Incorrect unused-import warning in ghci	Berengal		"Try to load the following in ghci with -fwarn-unused-imports:

{{{
import Prelude hiding (zip)

zip :: [a] -> [b] -> [(a,b)]
zip _ _ = []
}}}

It spits out the usual warning for unused imports:
{{{
    Warning: The import of `Prelude' is redundant
               except perhaps to import instances from `Prelude'
             To import instances alone, use: import Prelude()
}}}

When compiled with `ghc --make -fwarn-unused-imports` no warning is printed. Also, the following does not generate a warning in ghci:

{{{
import Prelude hiding (zip)

zip :: [a] -> [b] -> [(a,b)]
zip _ _ = undefined
}}}

I expect ghci and ghc to agree on the warnings unless there's a good reason not to, and I do not expect warnings about declarations to depend on their implementation."	bug	closed	normal		GHCi	6.12.1	worksforme			Unknown/Multiple	Unknown/Multiple	Incorrect warning at compile-time