Build warning: issue_5723_bootstrap

[treeman]

A clear build produces a couple of errors like:

rust/src/libsyntax/lib.rs:28:12: 28:32 warning: feature has added to rust, directive not necessary
rust/src/libsyntax/lib.rs:28 #![feature(issue_5723_bootstrap)]
...

The relevant issue #5723 was closed in favor of #16462 which has been closed, but the warnings remain.

[treeman]

Simply removing the directives does not seem to work:

rust/src/librustc/metadata/encoder.rs:1795:32: 1795:34 error: region bounds require `issue_5723_bootstrap`
rust/src/librustc/metadata/encoder.rs:1795 struct ImplVisitor<'a,'b:'a,'c:'a> {
...

[alexcrichton]

What version of rustc were you building? All these versions have been removed on master.

[treeman]

Oops, my mistake, I was using an older version.