[carnitine]

What does a standard programming language being unsound even imply? It’s not being used for theorem proving, so how is it of consequence?

[fabianhjr]

That it can produce contradictory results, if you have contradictions then at least one must be in error which means that following the language construction rules can produce erroneous results.

[UncleMeat]

You could imagine a semantics that produces different results depending on the order of inference rules.