I want to see yellow squiggles under logic errors. That will keep the programmers busy for a while.

Blue rather than yellow colored squiggles, but ReSharper (and I expect JetBrains IDEs in general) kind of does this.

It can point out things like unreachable code, redundant if predicates, suspicious casts and countless other things through realtime semantic analysis of code.

Of course there are infinitely more kinds of logic errors that simple static analysis like this can’t pick up, but an LLM “analysis” might.