Issue 4450 fix

[ashishdawale20]

This PR should fix issue #4450

[manfred-brands]

Thanks @ashishdawale20 for this PR.
This makes the error message for collections of strings much clearer.

[stevenaw]

@OsirisTerje @manfred-brands
I've noticed a few of the appveyor status checks stalling across PRs. I haven't looked into it myself yet, but is this a known issue or something that needs investigation?

[manfred-brands]

I had noticed it as well and had sent @OsirisTerje an email. It prevents me from merging otherwise approved PRs.

[OsirisTerje]

We should just remove the appveyor build. I have been just ignoring them. You can still merge even if the appveyor build stops.

[manfred-brands]

We should just remove the appveyor build. I have been just ignoring them. You can still merge even if the appveyor build stops.

I can't, it says Required statuses must pass before merging

[OsirisTerje]

Ok, then we just remove appveyor asap. Raised issue #4504

[OsirisTerje]

I have also removed the appveyor builds from the branch protection rules, so it should work now.