Minor proper subtype check optimization #12536
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Mypyc is bad at compiling nested functions. In one use case we were spending 7% of the mypy runtime just creating closure objects for `check_argument`. Here I manually inline the nested function to avoid this overhead. Work on #12526.
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mypy/subtypes.py
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| elif variance == CONTRAVARIANT: | ||
| nominal = nominal and self._is_proper_subtype(ra, ta) | ||
| else: | ||
| nominal = nominal and mypy.sametypes.is_same_type(ta, ra) | ||
| else: | ||
| nominal = nominal and mypy.sametypes.is_same_type(ta, ra) |
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What about adding if nominal: break here? Looks like we're needlessly rerunning the loop if a previous iteration already set nominal = True
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We are doing nominal and ... so a further iteration could still make it false?
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Ah true, I misread. But then we can break immediately if anything sets it to False, right?
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That seems to be the case. I'll update this.
Co-authored-by: Jelle Zijlstra <[email protected]>
JelleZijlstra
approved these changes
Apr 7, 2022
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According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
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Mypyc is bad at compiling nested functions. In one use case
we were spending 7% of the mypy runtime just creating closure
objects for
check_argument. Here I manually inline the nestedfunction to avoid this overhead.
Work on #12526.