Problem with merge when renaming

Hi,

I think I found a problem when you move a file into a directory of the
same name.  Here's what I did.

In a repository I created a directory with a file in it.  Commit it.
Then I move the file into a tmp name, make a directory with that name,
and move it into the directory.
git-mv dir/foo dir/foo.bin
mkdir dir/foo
git-mv dir/foo.bin dir/foo/foo.bin

Then in another branch I make a completely unrelated change.  I create
a file in another directory.

If I try to merge in the changes from the other branch or if the other
branch tries to merge in these changes I get this error:

dir/foo/foo.bin: unmerged (257cc5642cb1a054f08cc83f2d943e56fd3ebe99)
fatal: git-write-tree: error building trees
Merge with strategy recursive failed.

This is the script I've been using
#!/bin/bash
#

# Make sure it's all clean
rm -rf git-repo

mkdir git-repo
pushd git-repo
git-init
mkdir dir
git-add dir
pushd dir
echo foo > foo
git-add foo
popd
git-commit -a -m "one"
popd

# Developer A moves file into dir of same name
pushd git-repo
git-checkout -b branch-a
git-mv dir/foo dir/foo.bin
mkdir dir/foo
git-mv dir/foo.bin dir/foo/foo.bin
git-commit -a -m "File renamed"
git-checkout master
popd

# Developer B makes completely unrelated changes.
pushd git-repo
git-checkout -b branch-b
echo baz > foo.txt
echo bar > bar.txt
git-add bar.txt
git-add foo.txt
git-commit -a -m "unrelated changes"
git-checkout master
popd

# Developer A wants to merge changes from B
pushd git-repo
#git-merge branch-a
echo
#git-merge branch-b
#popd