Top rust issues

Doctests don't work in bin targets, non-public items

A-doctests C-enhancement T-rustdoc

Tracking issue for RFC 2141: Add support to Cargo for alternative registries

B-RFC-approved C-tracking-issue T-cargo

Tracking issue for #[cfg(target_has_atomic = ...)]

A-attributes B-unstable C-tracking-issue T-lang

compare compiler performance with `hashbrown`

I-compiletime P-medium T-compiler

Tracking issue for stmt_expr_attributes: Add attributes to expressions, etc.

A-grammar B-RFC-implemented B-unstable C-tracking-issue T-lang

Array lengths don't support generic parameters.

A-const-fn A-const-generics A-lazy-normalization C-bug D-confusing I-ICE T-compiler glacier

Use 'mut' as alias for 'let mut'

A-diagnostics A-suggestion-diagnostics C-enhancement D-newcomer-roadblock E-easy E-help-wanted E-mentor P-medium T-compiler

Tracking issue for RFC 1624: `break` with values for `loop`

B-RFC-approved B-unstable E-easy E-mentor T-lang final-comment-period

Mark &mut pointers as noalias once LLVM no longer miscompiles them

A-LLVM A-codegen C-enhancement I-slow

Tracking issue for `step_by` stabilization

B-unstable C-tracking-issue E-help-wanted E-mentor P-medium T-libs disposition-merge finished-final-comment-period