“Not optimized: Bad value context for arguments value”

Adding a property to one function, but not all functions, causes Not optimized flag on function containing Function.prototype.apply.

Cause

“V8 only recognizes monomorphic .apply call-sites” - @mraleph

Example

See example.js

Fixes

• Don’t attach properties to functions
• Copy arguments to an array. See https://github.com/GoogleChrome/devtools-docs/issues/53#issuecomment-51941358
• Provide a monomorphic .apply call-site (see fix.js)

Test in node

node --trace_opt --trace_deopt example.js | grep "failed to optimize dispatch"

Test in browser

jspm install
http-server  # open http://localhost:8080/