If early error is deferred then it's no longer early... that's all I meant by skipped. It still is a semantic change that's unrelated to a binary AST.

Indeed it's a semantic change. Are you saying you'd like that change to be proposed separately? That can't be done for the text format for the obvious compat reasons. It also has very little value on its own, as it is only one of many things that prevents actually skipping inner functions during parsing.