I modified the code so that Union-related Analyzers, which had been terminated, would now perform analysis.
As for the bug, red underlines don't appear in the source code (I wonder what caused this - I feel like I've encountered this before but can't remember at all).
However, since errors are still displayed in the error list when building, I suppose this is within acceptable limits.

Additionally, when SuppressSourceGeneration=true, I made it not parse the fields.
While there is a side effect that the Analyzer doesn't check all fields, I think it's fine to consider execution permission as almost equivalent.
Whether it's Visual Studio that's the problem, or if it's the v3 architecture that combines Source Generator and Analyzer - there are quite puzzling behaviors when it comes to error reporting.