[Python-Dev] Can Python implementations reject semantically invalid expressions?

[Steven D'Aprano]

This question was inspired by something asked on #python today. Consider 
it a hypothetical, not a serious proposal.

We know that many semantic errors in Python lead to runtime errors, e.g. 
1 + "1". If an implementation rejected them at compile time, would it 
still be Python? E.g. if the keyhole optimizer raised SyntaxError (or 
some other exception) on seeing this:

def f():
    return 1 + "1"

instead of compiling something which can't fail to raise an exception, 
would that still be a legal Python implementation?


-- 
Steven D'Aprano