calc-errors.html test at line 68

At line 68 of the test above, there is a calc() function with 128 nested parentheses. Firefox is able to support 128 pairs of nested parentheses. Blink supports 32 nested pairs of parentheses and then fails when trying 33 nested pairs of parentheses:

trac-webkit-calc-errors.html with 33 nested pairs of parentheses

128 nested pairs of parentheses seems outrageously extreme but there seems nothing in the CSS3 spec and CSS4 spec that indicate ceiling limit for nested parentheses.

Proposal: CSS4 spec explicitly state a limit (ceiling) of support to 32 nested pairs of parentheses in calc() function.

Then the test calc-errors.html should be adjusted accordingly before submitted to wpt.