sympy/sympy — pull request #8705 by dqnykamp (2014-12-27 14:41:33+00:00)
Title: In parse_expr with implicit multiplication, check if parentheses match.

Fixes problem that

parse_expr("(1,2),(3,4]", transformations=standard_transformations + (implicit_multiplication,))

does not raise exception but returns ((1,2),)