[Harmony proxies] "if a trap is missing"
bruant.d at gmail.com
Tue Dec 6 14:13:42 PST 2011
"All traps are optional. If missing (more precisely, if
handler[trapName] returns undefined), the proxy defaults to forwarding
the intercepted operation to its target object." 
In this case, the description says that the operation is forwarded. I
would prefer a TypeError to be thrown in this case.
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