[bpshaver]

Hard to conceive of a case where that would occur. Can you think of one?

The implication of what you're saying seems to be that if you're concerned about some kind of correctness you should be writing unit tests anyway and not being so fussed about type checking in a language like Python. I suppose if you are strictly following TDD that might work, but in all other cases type checks give you feedback much more quickly than unit tests ever can. I guess I don't understand.

[igouy]

Any old math with consistent types and incorrect calculation? (If only we'd diff'd the output with some known result.)

No doubt we're at cross purposes.

I'm a little surprised that you haven't mentioned — "Program testing can be used to show the presence of bugs, but never to show their absence!" (or existential versus universal quantification).

[bpshaver]

I'm afraid you lost me.