w3c/web-platform-tests — pull request #974 by caitp (2014-05-08 19:55:08+00:00)
Title: Test should be for compliance with actual spec

Though the specification may change in the future, the current literature says to throw a SyntaxError here.

Since these tests verify that a user agent complies with the actual literature, and not a proposed future literature, it is appropriate to assert that the thrown assertion is a SyntaxError rather than a TypeError, for the time being.