Pick up changes from master to 2.065 branch

I hope this will become the last cherry-picking for dmd.

One regression fix:
[REG2.065a] Issue 12197 - 'invalid array operation' errror message with valid array operation

Two ICE fixes:
Issue 12161 - ICE with "with" and alias this
Issue 12201 - Crash on forward reference import within mixed in template