The initial implementation of PEP 709 didn't bother to clear comprehension locals after an inlined comprehension, if the name was a global outside the comprehension. This was purely an optimization to save a couple extra instructions in this case; it didn't seem necessary to clear the comprehension value, since outer references to the name would use LOAD_GLOBAL anyway and not see the value in fastlocals.

But it is necessary to clear the comprehension local even in this case, because otherwise it will still show up in locals(), or in debugger usage, outside of the comprehension.

• Issue: PEP 709: Comprehension iteration variable leaks into outer locals() #104619