Get rid of references to the refractored libsyntax crate (#598)

* Get rid of references to the refractored `libsyntax` crate

* Apply suggestions from code review

Co-authored-by: Yuki Okushi <huyuumi.dev@gmail.com>

Author: LeSeulArtichaut

src/appendix/code-index.md

@@ -8,24 +8,24 @@ Item            |  Kind    | Short description           | Chapter            |
 ----------------|----------|-----------------------------|--------------------|-------------------
 `BodyId` | struct | One of four types of HIR node identifiers | [Identifiers in the HIR] | [src/librustc_hir/hir.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/struct.BodyId.html)
 `Compiler` | struct | Represents a compiler session and can be used to drive a compilation. | [The Rustc Driver and Interface] | [src/librustc_interface/interface.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_interface/interface/struct.Compiler.html)
-`ast::Crate` | struct | A syntax-level representation of a parsed crate | [The parser] | [src/libsyntax/ast.rs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast/struct.Crate.html)
+`ast::Crate` | struct | A syntax-level representation of a parsed crate | [The parser] | [src/librustc_ast/ast.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/struct.Crate.html)
 `rustc_hir::Crate` | struct | A more abstract, compiler-friendly form of a crate's AST | [The Hir] | [src/librustc_hir/hir.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/struct.Crate.html)
 `DefId` | struct | One of four types of HIR node identifiers | [Identifiers in the HIR] | [src/librustc_hir/def_id.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/def_id/struct.DefId.html)
 `DiagnosticBuilder` | struct | A struct for building up compiler diagnostics, such as errors or lints | [Emitting Diagnostics] | [src/librustc_errors/diagnostic_builder.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/struct.DiagnosticBuilder.html)
 `DocContext` | struct | A state container used by rustdoc when crawling through a crate to gather its documentation | [Rustdoc] | [src/librustdoc/core.rs](https://github.com/rust-lang/rust/blob/master/src/librustdoc/core.rs)
 `HirId` | struct | One of four types of HIR node identifiers | [Identifiers in the HIR] | [src/librustc_hir/hir_id.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir_id/struct.HirId.html)
-`NodeId` | struct | One of four types of HIR node identifiers. Being phased out | [Identifiers in the HIR] | [src/libsyntax/ast.rs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/node_id/struct.NodeId.html)
-`P` | struct | An owned immutable smart pointer. By contrast, `&T` is not owned, and `Box<T>` is not immutable. | None | [src/syntax/ptr.rs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ptr/struct.P.html)
+`NodeId` | struct | One of four types of HIR node identifiers. Being phased out | [Identifiers in the HIR] | [src/librustc_ast/ast.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/node_id/struct.NodeId.html)
+`P` | struct | An owned immutable smart pointer. By contrast, `&T` is not owned, and `Box<T>` is not immutable. | None | [src/librustc_ast/ptr.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ptr/struct.P.html)
 `ParamEnv` | struct | Information about generic parameters or `Self`, useful for working with associated or generic items | [Parameter Environment] | [src/librustc/ty/mod.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/struct.ParamEnv.html)
-`ParseSess` | struct | This struct contains information about a parsing session | [The parser] | [src/libsyntax/parse/mod.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_session/parse/struct.ParseSess.html)
+`ParseSess` | struct | This struct contains information about a parsing session | [The parser] | [src/librustc_session/parse/parse.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_session/parse/struct.ParseSess.html)
 `Query` | struct | Represents the result of query to the `Compiler` interface and allows stealing, borrowing, and returning the results of compiler passes. | [The Rustc Driver and Interface] | [src/librustc_interface/queries.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_interface/queries/struct.Query.html)
 `Rib` | struct | Represents a single scope of names | [Name resolution] | [src/librustc_resolve/lib.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_resolve/late/struct.Rib.html)
 `Session` | struct | The data associated with a compilation session | [The parser], [The Rustc Driver and Interface] | [src/librustc/session/mod.html](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_session/struct.Session.html)
 `SourceFile` | struct | Part of the `SourceMap`. Maps AST nodes to their source code for a single source file. Was previously called FileMap | [The parser] | [src/librustc_span/lib.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/struct.SourceFile.html)
 `SourceMap` | struct | Maps AST nodes to their source code. It is composed of `SourceFile`s. Was previously called CodeMap | [The parser] | [src/librustc_span/source_map.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/source_map/struct.SourceMap.html)
 `Span` | struct  | A location in the user's source code, used for error reporting primarily | [Emitting Diagnostics] | [src/librustc_span/span_encoding.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/struct.Span.html)
 `StringReader` | struct | This is the lexer used during parsing. It consumes characters from the raw source code being compiled and produces a series of tokens for use by the rest of the parser | [The parser] |  [src/librustc_parse/lexer/mod.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_parse/lexer/struct.StringReader.html)
-`syntax::token_stream::TokenStream` | struct | An abstract sequence of tokens, organized into `TokenTree`s | [The parser], [Macro expansion] | [src/libsyntax/tokenstream.rs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/tokenstream/struct.TokenStream.html)
+`rustc_ast::token_stream::TokenStream` | struct | An abstract sequence of tokens, organized into `TokenTree`s | [The parser], [Macro expansion] | [src/librustc_ast/tokenstream.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/tokenstream/struct.TokenStream.html)
 `TraitDef` | struct | This struct contains a trait's definition with type information | [The `ty` modules] |  [src/librustc/ty/trait_def.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/trait_def/struct.TraitDef.html)
 `TraitRef` | struct | The combination of a trait and its input types (e.g. `P0: Trait<P1...Pn>`) | [Trait Solving: Goals and Clauses], [Trait Solving: Lowering impls]  |  [src/librustc/ty/sty.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/struct.TraitRef.html)
 `Ty<'tcx>` | struct | This is the internal representation of a type used for type checking | [Type checking] | [src/librustc/ty/mod.rs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/ty/type.Ty.html)

src/appendix/glossary.md

@@ -7,7 +7,7 @@ them better.
 Term                    | Meaning
 ------------------------|--------
 arena/arena allocation  |  an _arena_ is a large memory buffer from which other memory allocations are made. This style of allocation is called _area allocation_. See [this chapter](../memory.md) for more info.
-AST                     |  the abstract syntax tree produced by the syntax crate; reflects user syntax very closely.
+AST                     |  the abstract syntax tree produced by the `rustc_ast` crate; reflects user syntax very closely.
 binder                  |  a "binder" is a place where a variable or type is declared; for example, the `<T>` is a binder for the generic type parameter `T` in `fn foo<T>(..)`, and \|`a`\|` ...` is a binder for the parameter `a`. See [the background chapter for more](./background.html#free-vs-bound)
 bound variable          |  a "bound variable" is one that is declared within an expression/term. For example, the variable `a` is bound within the closure expression \|`a`\|` a * 2`. See [the background chapter for more](./background.html#free-vs-bound)
 codegen                 |  the code to translate MIR into LLVM IR.

src/appendix/stupid-stats.md

@@ -61,7 +61,7 @@ Macros and syntax extensions are expanded, and `cfg` attributes will cause some
 code to disappear. The resulting AST won't have any macros or macro uses left
 in.
 
-The code for these first two phases is in [libsyntax](https://github.com/rust-lang/rust/tree/master/src/libsyntax).
+The code for these first two phases is in [librustc_ast](https://github.com/rust-lang/rust/tree/master/src/librustc_ast).
 
 After this phase, the compiler allocates ids to each node in the AST
 (technically not every node, but most of them). If we are writing out
@@ -356,7 +356,7 @@ struct StupidVisitor {
 
 The `StupidVisitor` struct just keeps track of the number of `println!`s it has
 seen and the count for each number of arguments. It implements
-`syntax::visit::Visitor` to walk the AST. Mostly we just use the default
+`rustc_ast::visit::Visitor` to walk the AST. Mostly we just use the default
 methods, these walk the AST taking no action. We override `visit_item` and
 `visit_mac` to implement custom behaviour when we walk into items (items include
 functions, modules, traits, structs, and so forth, we're only interested in

src/bug-fix-procedure.md

@@ -65,7 +65,7 @@ described in more detail below):
 1. Once the change has been in the wild for at least one cycle, we can
    **stabilize the change**, converting those warnings into errors.
 
-Finally, for changes to libsyntax that will affect plugins, the general policy
+Finally, for changes to `librustc_ast` that will affect plugins, the general policy
 is to batch these changes. That is discussed below in more detail.
 
 ### Tracking issue

src/diagnostics.md

@@ -322,12 +322,12 @@ like normal but invokes the lint with `buffer_lint`.
 
 #### Linting even earlier in the compiler
 
-The parser (`libsyntax`) is interesting in that it cannot have dependencies on
+The parser (`librustc_ast`) is interesting in that it cannot have dependencies on
 any of the other `librustc*` crates. In particular, it cannot depend on
 `librustc::lint` or `librustc_lint`, where all of the compiler linting
 infrastructure is defined. That's troublesome!
 
-To solve this, `libsyntax` defines its own buffered lint type, which
+To solve this, `librustc_ast` defines its own buffered lint type, which
 `ParseSess::buffer_lint` uses. After macro expansion, these buffered lints are
 then dumped into the `Session::buffered_lints` used by the rest of the compiler.
 
@@ -358,7 +358,7 @@ the structured JSON and see the "human" output (well, _sans_ colors)
 without having to compile everything twice.
 
 The "human" readable and the json format emitter can be found under
-librustc_errors, both were moved from the libsyntax crate to the
+librustc_errors, both were moved from the `librustc_ast` crate to the
 [librustc_errors crate](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_errors/index.html).
 
 The JSON emitter defines [its own `Diagnostic`

src/high-level-overview.md

@@ -7,7 +7,7 @@ there live many crates. These crates contain the sources for the
 standard library and the compiler.  This document, of course, focuses
 on the latter.
 
-Rustc consists of a number of crates, including `syntax`,
+Rustc consists of a number of crates, including `rustc_ast`,
 `rustc`, `rustc_target`, `rustc_codegen`, `rustc_driver`, and
 many more. The source for each crate can be found in a directory
 like `src/libXXX`, where `XXX` is the crate name.
@@ -33,7 +33,7 @@ rustc_codegen  rustc_borrowck   ...  rustc_metadata
                     rustc
                        |
                        v
-                    syntax
+                   rustc_ast
                     /    \
                   /       \
            rustc_span  rustc_builtin_macros
@@ -92,7 +92,7 @@ take:
 1. **Parsing input**
     - this processes the `.rs` files and produces the AST
       ("abstract syntax tree")
-    - the AST is defined in `src/libsyntax/ast.rs`. It is intended to match the lexical
+    - the AST is defined in `src/librustc_ast/ast.rs`. It is intended to match the lexical
       syntax of the Rust language quite closely.
 2. **Name resolution, macro expansion, and configuration**
     - once parsing is complete, we process the AST recursively, resolving

src/hir.md

@@ -100,7 +100,7 @@ sorts of identifiers in active use:
 [`DefId`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/def_id/struct.DefId.html
 [`HirId`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir_id/struct.HirId.html
 [`BodyId`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/struct.BodyId.html
-[`NodeId`]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/node_id/struct.NodeId.html
+[`NodeId`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/node_id/struct.NodeId.html
 
 We also have an internal map to go from `DefId` to what’s called "Def path". "Def path" is like a
 module path but a bit more rich. For example, it may be `crate::foo::MyStruct` that identifies

src/macro-expansion.md

@@ -1,6 +1,6 @@
 # Macro expansion
 
-> `libsyntax`, `librustc_expand`, and `librustc_builtin_macros` are all undergoing
+> `librustc_ast`, `librustc_expand`, and `librustc_builtin_macros` are all undergoing
 > refactoring, so some of the links in this chapter may be broken.
 
 Macro expansion happens during parsing. `rustc` has two parsers, in fact: the
@@ -361,24 +361,24 @@ be accessed from any Ident without any context) librustc_span/lib.rs - some
 secondary methods like macro backtrace using primary methods from hygiene.rs
 librustc_builtin_macros - implementations of built-in macros (including macro attributes
 and derives) and some other early code generation facilities like injection of
-standard library imports or generation of test harness.  libsyntax/config.rs -
+standard library imports or generation of test harness.  librustc_ast/config.rs -
 implementation of cfg/cfg_attr (they treated specially from other macros),
-should probably be moved into libsyntax/ext.  libsyntax/tokenstream.rs +
-libsyntax/parse/token.rs - structures for compiler-side tokens, token trees,
-and token streams.  libsyntax/ext - various expansion-related stuff
-libsyntax/ext/base.rs - basic structures used by expansion
-libsyntax/ext/expand.rs - some expansion structures and the bulk of expansion
+should probably be moved into librustc_ast/ext.  librustc_ast/tokenstream.rs +
+librustc_ast/parse/token.rs - structures for compiler-side tokens, token trees,
+and token streams.  librustc_ast/ext - various expansion-related stuff
+librustc_ast/ext/base.rs - basic structures used by expansion
+librustc_ast/ext/expand.rs - some expansion structures and the bulk of expansion
 infrastructure code - collecting macro invocations, calling into resolve for
 them, calling their expanding functions, and integrating the results back into
-AST libsyntax/ext/placeholder.rs - the part of expand.rs responsible for
+AST librustc_ast/ext/placeholder.rs - the part of expand.rs responsible for
 "integrating the results back into AST" basicallly, "placeholder" is a
 temporary AST node replaced with macro expansion result nodes
-libsyntax/ext/builer.rs - helper functions for building AST for built-in macros
+librustc_ast/ext/builer.rs - helper functions for building AST for built-in macros
 in librustc_builtin_macros (and user-defined syntactic plugins previously), can probably
-be moved into librustc_builtin_macros these days libsyntax/ext/proc_macro.rs +
-libsyntax/ext/proc_macro_server.rs - interfaces between the compiler and the
+be moved into librustc_builtin_macros these days librustc_ast/ext/proc_macro.rs +
+librustc_ast/ext/proc_macro_server.rs - interfaces between the compiler and the
 stable proc_macro library, converting tokens and token streams between the two
-representations and sending them through C ABI libsyntax/ext/tt -
+representations and sending them through C ABI librustc_ast/ext/tt -
 implementation of macro_rules, turns macro_rules DSL into something with
 signature Fn(TokenStream) -> TokenStream that can eat and produce tokens,
 @mark-i-m knows more about this librustc_resolve/macros.rs - resolving macro
@@ -408,8 +408,8 @@ piece of AST, etc), this is an enum that lists them
 ProcMacro/TTMacroExpander/AttrProcMacro/MultiItemModifier - traits representing
 the expander signatures (TODO: change and rename the signatures into something
 more consistent) trait Resolver - a trait used to break crate dependencies (so
-resolver services can be used in libsyntax, despite librustc_resolve and pretty
-much everything else depending on libsyntax) ExtCtxt/ExpansionData - various
+resolver services can be used in librustc_ast, despite librustc_resolve and pretty
+much everything else depending on librustc_ast) ExtCtxt/ExpansionData - various
 intermediate data kept and used by expansion infra in the process of its work
 AstFragment - a piece of AST that can be produced by a macro (may include
 multiple homogeneous AST nodes, like e.g. a list of items) Annotatable - a

src/name-resolution.md

@@ -20,7 +20,7 @@ namespaces and therefore can co-exist.
 The name resolution in Rust is a two-phase process. In the first phase, which runs
 during macro expansion, we build a tree of modules and resolve imports. Macro
 expansion and name resolution communicate with each other via the `Resolver`
-trait, defined in `libsyntax`.
+trait, defined in `librustc_ast`.
 
 The input to the second phase is the syntax tree, produced by parsing input
 files and expanding macros. This phase produces links from all the names in the

src/test-implementation.md

@@ -31,14 +31,14 @@ How does any sort of `main` function invoke these tests if they're not visible?
 What exactly is `rustc --test` doing?
 
 `#[test]` is implemented as a syntactic transformation inside the compiler's
-[`libsyntax` crate][libsyntax]. Essentially, it's a fancy macro, that
+[`librustc_ast` crate][librustc_ast]. Essentially, it's a fancy macro, that
 rewrites the crate in 3 steps:
 
 #### Step 1: Re-Exporting
 
 As mentioned earlier, tests can exist inside private modules, so we need a
 way of exposing them to the main function, without breaking any existing
-code. To that end, `libsyntax` will create local modules called
+code. To that end, `librustc_ast` will create local modules called
 `__test_reexports` that recursively reexport tests. This expansion translates
 the above example into:
 
@@ -78,7 +78,7 @@ hygiene.
 
 #### Step 2: Harness Generation
 Now that our tests are accessible from the root of our crate, we need to do
-something with them. `libsyntax` generates a module like so:
+something with them. `librustc_ast` generates a module like so:
 
 ```rust,ignore
 #[main]
@@ -115,7 +115,7 @@ fn foo() {
 This means our tests are more than just simple functions, they have
 configuration information as well. `test` encodes this configuration data
 into a struct called [`TestDesc`][TestDesc]. For each test function in a
-crate, `libsyntax` will parse its attributes and generate a `TestDesc`
+crate, `librustc_ast` will parse its attributes and generate a `TestDesc`
 instance. It then combines the `TestDesc` and test function into the
 predictably named `TestDescAndFn` struct, that `test_main_static` operates
 on. For a given test, the generated `TestDescAndFn` instance looks like so:
@@ -146,7 +146,7 @@ $ rustc my_mod.rs -Z unpretty=hir
 
 [test]: https://doc.rust-lang.org/test/index.html
 [TestDesc]: https://doc.rust-lang.org/test/struct.TestDesc.html
-[Symbol]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast/struct.Ident.html
-[Ident]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast/struct.Ident.html
+[Symbol]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/struct.Ident.html
+[Ident]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/struct.Ident.html
 [eRFC]: https://github.com/rust-lang/rfcs/blob/master/text/2318-custom-test-frameworks.md
-[libsyntax]: https://github.com/rust-lang/rust/tree/master/src/libsyntax
+[librustc_ast]: https://github.com/rust-lang/rust/tree/master/src/librustc_ast