Fix BinExport's "tight loop" feature extraction.

[larchchen]

idx.target_edges_by_basic_block_index[basic_block_index] is of type List[Edges]. The index basic_block_index was definitely not an element.

Checklist

• [x] No CHANGELOG update needed
• [x] No new tests needed
• [x] No documentation update needed

[mr-tz]

thanks!

[mr-tz]

something seems off here, investigating that this reports functions like this as having a tight loop:

[williballenthin]

bummer that mypy didn't catch this, oh well

[williballenthin]

After some investigating, mypy correct determines that the list contains edge instances and the index is an int, but doesn't complain that "an int will never be found in a list of edges". Perhaps that sort of lint has too many false positives (since objects might overload their __in__ methods???) or something. Too bad.

[williballenthin]

something seems off here, investigating that this reports functions like this as having a tight loop:

There was a bug in the second line of the patch, it should be:

target_edges contains a list of all edges that terminate at the given basic block. So we need to inspect the list for edges that also source from that block.

I've pushed a fix to the branch.