This time, when completing the keyword (e.g. `fn` + whitespace).
The bug was actually a double-bug:
First, we did not resolve the impl in the macro-expanded file but in the real file, which of course cannot work.
Second, in analysis the whitespace was correlated with the `impl` and not the incomplete `fn`, which caused fake (where we insert an identifier after the whitespace) and real expansions to go out of sync, which failed analysis. The fix is to skip whitespaces in analysis.