http://ecma-international.org/ecma-262/6.0/#sec-for-statement-static-semantics-early-errors for (let v = 42;;) { var v = 44; } should throw SyntaxError http://ecma-international.org/ecma-262/6.0/#sec-try-statement-static-semantics-early-errors try { } catch (error) { let error = 42; } should throw SyntaxError try { } catch (error) { var error = 42; } should throw SyntaxError