Return Option rather than fail for shift_ref, mut_shift_ref, pop_ref, mut_pop_ref, and mut_last#11944

Merged

bors merged 3 commits intorust-lang:masterfrom

nathanielherman:vec_opt

Feb 1, 2014

Commits on Jan 30, 2014

Make shift_ref and mut_shift_ref return Option instead of failing
nathanielherman
committed
Make pop_ref and mut_pop_ref return Option instead of failing on empty vectors
nathanielherman
committed
Make mut_last return Option instead of failing on empty vector (and add a test for mut_last)
nathanielherman
committed