http://www.ecma-international.org/ecma-262/6.0/#sec-keywords

Some throw correctly: for, implements, ...

• Some don't: enum, await
• Some are supposed to be usable in script mode (non-strict) but don't: let (need to test other envs if this is true)

This list is probably not complete.