id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
4424	Dynamically set -hide-all-packages is being ignored.	nominolo	simonmar	"Consider the following two alternative ways of specifying dynflags:
{{{
./inplace/bin/ghc-stage2 --interactive -hide-all-packages -package base
GHCi, version 7.1.20101013: http://www.haskell.org/ghc/  :? for help
[...]
Prelude> import Control.Monad.State.Strict

<no location info>:
    Could not find module `Control.Monad.State.Strict':
      It is a member of the hidden package `monads-fd-0.1.0.2'.
      It is a member of the hidden package `mtl-1.1.1.0'.
      Use -v to see a list of the files searched for.
}}}

Now, instead of specifying the flags on startup we set them after startup:
{{{
./inplace/bin/ghc-stage2 --interactive
GHCi, version 7.1.20101013: http://www.haskell.org/ghc/  :? for help
[...]
Prelude> import Control.Monad.State.Strict

<no location info>:
    Ambiguous module name `Control.Monad.State.Strict':
      it was found in multiple packages: monads-fd-0.1.0.2 mtl-1.1.1.0
Prelude> :set -hide-all-packages
Prelude> import Control.Monad.State.Strict

<no location info>:
    Ambiguous module name `Control.Monad.State.Strict':
      it was found in multiple packages: monads-fd-0.1.0.2 mtl-1.1.1.0
}}}

The interactive call to `:set -hide-all-packages` is ignored.  The same happens inside the GHC API (which is causing me problems).

You need to have both `mtl` and `monads-fd` installed to get the above error.
"	bug	closed	normal		Compiler	6.13	fixed			Unknown/Multiple	Unknown/Multiple	None/Unknown