mozilla/app-validator — pull request #36 by bnjbvr (2014-10-10 15:29:54+00:00)
Title: Take inherited contexts into accounts for closure functions (bug 1081134)

This prevents test_function_scope_block to fail, when run with Spidermonkey. The IIFE doesn't inherit the context from its outer function expression, so x is actually never found. Somehow, this was triggered for !expr but not for other kinds of expr.