Support SequenceExpression (i.e., comma operator)

[falsandtru]

code:

assert((-0, -1) === -0 + (-1));

expected:

  assert((-0, -1) + 1 === -0 + (-1))
         ||   |   |   |   |  |  |
         |0   -1  |   |   |  |  -1
         -1       |   |   0  -1
                  0   false

actual:

  assert((-0, -1) + 1 === -0 + -1)
                  |   |   |  | |
                  |   |   |  | -1
                  |   |   0  -1
                  0   false

[falsandtru]

ping @twada

[twada]

@falsandtru Thank you for reporting. I'll take a look.

[twada]

@falsandtru Sorry for the too late response, I've implemented SequenceExpression (i.e., comma operator) support this summer(!) so I close this issue now. Please feel free to reopen this issue if you have any problems.