[mypyc] Fix evaluation of iterable in list comprehension twice #10599
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This could result in a crash if the second evaluation results in a shorter list, such as in this example (besides being incorrect overall): ``` a = [s for s in f.readlines()] ``` `f.readlines()` was called twice, resulting in an empty list on the second call. This caused the list object to have a NULL item, which is invalid. This should fix `mypy --install-types` in compiled mode.
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This could result in a crash if the second evaluation results
in a shorter list, such as in this example (besides being incorrect
overall):
f.readlines()was called twice, resulting in an empty list onthe second call. This caused the list object constructed in the
comprehension to have a NULL item, which is invalid.
This fixes
mypy --install-typesin compiled mode.Fixes #10596.