Auto merge of #59256 - petrochenkov:derval2, r=Zoxc

2019-03-25T12:21:46+00:00

Make meta-item API compatible with `LocalInternedString::get` soundness fix r? @Zoxc

Remove methods is_struct/is_tuple/is_unit from VariantData

2019-03-24T09:10:16+00:00

Make meta-item API compatible with `LocalInternedString::get` soundness fix

2019-03-17T14:04:58+00:00

syntax: Do not accidentally treat multi-segment meta-items as single-segment

2019-03-16T20:13:15+00:00

rustc: doc comments

2019-02-10T23:42:32+00:00

Support const generics in derive

2019-02-07T14:02:16+00:00

Co-Authored-By: Gabriel Smith

Rollup merge of #58133 - taiki-e:libsyntax_ext-2018, r=Centril

2019-02-07T05:57:40+00:00

libsyntax_ext => 2018 Transitions `libsyntax_ext` to Rust 2018; cc #58099 r? @Centril

Overhaul `syntax::fold::Folder`.

2019-02-05T22:06:27+00:00

This commit changes `syntax::fold::Folder` from a functional style (where most methods take a `T` and produce a new `T`) to a more imperative style (where most methods take and modify a `&mut T`), and renames it `syntax::mut_visit::MutVisitor`. The first benefit is speed. The functional style does not require any reallocations, due to the use of `P::map` and `MoveMap::move_{,flat_}map`. However, every field in the AST must be overwritten; even those fields that are unchanged are overwritten with the same value. This causes a lot of unnecessary memory writes. The imperative style reduces instruction counts by 1--3% across a wide range of workloads, particularly incremental workloads. The second benefit is conciseness; the imperative style is usually more concise. E.g. compare the old functional style: ``` fn fold_abc(&mut self, abc: ABC) { ABC { a: fold_a(abc.a), b: fold_b(abc.b), c: abc.c, } } ``` with the imperative style: ``` fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) { visit_a(a); visit_b(b); } ``` (The reductions get larger in more complex examples.) Overall, the patch removes over 200 lines of code -- even though the new code has more comments -- and a lot of the remaining lines have fewer characters. Some notes: - The old style used methods called `fold_*`. The new style mostly uses methods called `visit_*`, but there are a few methods that map a `T` to something other than a `T`, which are called `flat_map_*` (`T` maps to multiple `T`s) or `filter_map_*` (`T` maps to 0 or 1 `T`s). - `move_map.rs`/`MoveMap`/`move_map`/`move_flat_map` are renamed `map_in_place.rs`/`MapInPlace`/`map_in_place`/`flat_map_in_place` to reflect their slightly changed signatures. - Although this commit renames the `fold` module as `mut_visit`, it keeps it in the `fold.rs` file, so as not to confuse git. The next commit will rename the file.

libsyntax_ext => 2018

2019-02-04T12:49:54+00:00

Remove licenses

2018-12-26T04:08:33+00:00

rust/src/libsyntax_ext/deriving/generic/mod.rs, branch 1.35.0