Add rustc_on_unimplemented for Index implementation on slice#31071

Closed

GuillaumeGomez wants to merge 2 commits intorust-lang:masterfrom

GuillaumeGomez:index_indication

Commits on Mar 10, 2016

Extend rustc_on_unimplemented flag: if a message is available at an impl, this message will be displayed instead
GuillaumeGomez
committed
Improve error message for Index trait on slices
GuillaumeGomez
committed