mozilla/rhino — pull request #66 by anba (2012-07-27 09:47:39+00:00)
Title: Patch for bug 637811:

LabeledStatement uses EXPR_VOID as its type, that means AstNode#hasSideEffects() uses the default case (=> it returns false). So every labelled statement gets the "code has no side effects" warning, which is clearly wrong.