I just 'wasted' some time on a quickfix problem, which might be related to others already posted in this forum:

Imagine a instance with a port map sporting a signal 'too much', i.e. missing in the port definition of entity and component.

The problem is flagged as 'could not find declaration of signal' and quickfix offers to 'generate signal declaration'. This should have made me suspicious, since the signal in question is in the port map's left column.
But I tried it anyway, with the result, that nothing happened (apparently).
So I went on adding the port manually, but the problem marker still did not disappear.

I found that the attempt to quickfix had created an incomplete signal declaration (which also created a problem marker that I overlooked) which conflicted with my manual update to the port definition. But as already posted by Simon, multiple declarations are reported as 'missing' instead of 'ambiguous', leading to my 'waste of time' :-)

But anyway, quickfix should update the port definition. Adding a signal is not the right fix in this case.

Regards,
Kurt.