bpo-18374: fix wrong col_offset of some ast.BinOp instances (GH-14607)


Nested BinOp instances (e.g. a+b+c) had a wrong col_offset for the
second BinOp (e.g. 2 instead of 0 in the example). Fix it by using the
correct st node to copy the line and col_offset from in ast.c.
(cherry picked from commit 110a47c4f42cf4db88edc1876899fff8f05190fb)

Co-authored-by: Carl Friedrich Bolz-Tereick <cfbolz@gmx.de>
4 files changed