Bug! Git merge also fails with a wrong error message

I have updates to this issue.

After asking several people who didn't believe me, after all I could pass all checks to ensure that the file in question really is tracked, despite the error message telling it is not. (The file has a history, it is part of the branch, git status behaves as expected when I rename it, and so on.)

I had found a workaround hack to access my data again: I have cloned the repo into another directory, then switched to the branch in there (it actually worked) and used BeyondCompare to manually(!) switch my original repo and working directory by copying some (not all) files in .git and all differences in the working directory.

That worked fine at first, I could commit to that branch.

Today I wanted to merge that branch into master again. Switching to master was fine, but merging from the form-refactoring branch now fails for the very same "reason":

----- git.exe merge --no-commit form-refactoring

error: The following untracked working tree files would be overwritten by merge: Form1.Designer.cs Please move or remove them before you can merge. Aborting -----

Again, that file is NOT untracked. Git just fails processing its own data. I cannot move that file because it is part of the other branch and must be merged now.

Am I now supposed to checkout both branches and do the merge somehow on my own?

Maybe it's not a good idea to use branching and then rename, create and delete files on that branch, as switching and merging fail completely afterwards. And in the end, maybe Git isn't all that good and some of the alternatives with real file tracking should be preferred.

I, for one, have lost a great amount of trust in Git in the last two days.

(Sorry for the formatting mess, but the stupid Gmane post editor forced me to do that or it wouldn't accept my message... Don't you have a real mailing list, if there's no web forum??)