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Optimise LiteralType.__eq__ and __hash__#20423
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If I'm doing it right, this should be 2% on a profile I'm looking at
According tomypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
| ifself._hash==-1: | ||
| self._hash=hash((self.value,self.fallback)) | ||
| returnself._hash | ||
| returnhash(self.value) |
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Is this part actually safe? This will makeLiteral["foo"] andLiteral[b"foo"] have same hash (I don't remember why, but we always store the literal bytes value as a string).
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There's alsoLiteral[0] vsLiteral[False], both 0 and False hash to zero IIRC
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It's fine for hashes to collide and doesn't affect correctness. You just don't want too many values to collide because then some of your constant time operations become linear.
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Only correctness requirement is that values that compare equal have the same hash
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If I'm doing it right, this should be 1-2% on a profile I'm looking at