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Replaced "len" by "length", to match the given code example.

Replaced "len" by "length", to match the given code example.
bors added a commit that referenced this pull request Apr 23, 2014
Replaced "len" by "length", to match the given code example.
@bors bors closed this Apr 23, 2014
@bors bors merged commit f495723 into rust-lang:master Apr 23, 2014
@aochagavia aochagavia deleted the pr branch April 27, 2014 14:48
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 5, 2023
…=Veykril

Introduce macro sub-namespaces and `macro_use` prelude

This PR implements two mechanisms needed for correct macro name resolution: macro sub-namespace and `macro_use` prelude.

- [macro sub-namespaces][subns-ref]

  Macros have two sub-namespaces: one for function-like macro and the other for those in attributes (including custom derive macros). When we're resolving a macro name for function-like macro, we should ignore non-function-like macros, and vice versa.

  This helps resolve single-segment macro names because we can (and should, as rustc does) fallback to names in preludes when the name in the current module scope is in different sub-namespace.

- [`macro_use` prelude][prelude-ref]

  `#[macro_use]`'d extern crate declarations (including the standard library) bring their macros into scope, but they should not be prioritized over local macros (those defined in place and those explicitly imported).

  We have been bringing them into legacy (textual) macro scope, which has the highest precedence in name resolution. This PR introduces the `macro_use` prelude in crate-level `DefMap`s, whose precedence is lower than local macros but higher than the standard library prelude.

The first 3 commits are drive-by fixes/refactors.

Fixes rust-lang#8828 (prelude)
Fixes rust-lang#12505 (prelude)
Fixes rust-lang#12734 (prelude)
Fixes rust-lang#13683 (prelude)
Fixes rust-lang#13821 (prelude)
Fixes rust-lang#13974 (prelude)
Fixes rust-lang#14254 (namespace)

[subns-ref]: https://doc.rust-lang.org/reference/names/namespaces.html#sub-namespaces
[prelude-ref]: https://doc.rust-lang.org/reference/names/preludes.html#macro_use-prelude
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