Fix validity period of derived SingleDenotations #19983
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smarter
added
the
backport:nominated
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test performance please |
1 similar comment
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test performance please |
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performance test scheduled: 148 job(s) in queue, 1 running. |
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Performance test finished successfully: Visit https://dotty-bench.epfl.ch/19983/ to see the changes. Benchmarks is based on merging with main (a36849f) |
When running:
val f: ( => Int) => Int = i => i ; f(1)
twice in the REPL, the second time crashed with a ClassCastException.
The difference is that in the second run, the denotation for `f.apply` is
created from the SymDenotation for `Function1#apply` which already exists and is
known to be valid in every phase, but that doesn't mean that the derived
denotation for `f.apply` has the same validity: unlike the SymDenotation it
needs to be transformed (in particular to run the `ElimByName` transformer).
It turns out that there were multiple places in the compiler where we created a
new denotation with a validity based on the existing one when this was not
legitimate. I've gone through all these places and replaced them by
`currentStablePeriod`.
Fixes scala#18756.
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Performance test finished successfully: Visit https://dotty-bench.epfl.ch/19983/ to see the changes. Benchmarks is based on merging with main (301c977) |
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Performance seems to be neutral or better. |
odersky
approved these changes
Mar 29, 2024
WojciechMazur
removed
the
backport:nominated
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When running:
twice in the REPL, the second time crashed with a ClassCastException.
The difference is that in the second run, the denotation for
f.applyis created from the SymDenotation forFunction1#applywhich already exists and is known to be valid in every phase, but that doesn't mean that the derived denotation forf.applyhas the same validity: unlike the SymDenotation it needs to be transformed (in particular to run theElimByNametransformer).It turns out that there were multiple places in the compiler where we created a new denotation with a validity based on the existing one when this was not legitimate. I've gone through all these places and replaced them by
currentStablePeriod.Fixes #18756.