move syntax::parse -> librustc_parse

also move MACRO_ARGUMENTS -> librustc_parse

67 files changed, 480 insertions, 424 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0f770f3eadb..7e51f96cfb8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3504,6 +3504,7 @@ dependencies = [
  "rustc_lint",
  "rustc_metadata",
  "rustc_mir",
+ "rustc_parse",
  "rustc_plugin",
  "rustc_plugin_impl",
  "rustc_save_analysis",
@@ -3571,6 +3572,7 @@ dependencies = [
  "rustc_lint",
  "rustc_metadata",
  "rustc_mir",
+ "rustc_parse",
  "rustc_passes",
  "rustc_plugin_impl",
  "rustc_privacy",
@@ -3648,6 +3650,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_index",
+ "rustc_parse",
  "rustc_target",
  "serialize",
  "smallvec 1.0.0",
@@ -3692,6 +3695,21 @@ dependencies = [
 ]
 
 [[package]]
+name = "rustc_parse"
+version = "0.0.0"
+dependencies = [
+ "bitflags",
+ "log",
+ "rustc_data_structures",
+ "rustc_errors",
+ "rustc_lexer",
+ "rustc_target",
+ "smallvec 1.0.0",
+ "syntax",
+ "syntax_pos",
+]
+
+[[package]]
 name = "rustc_passes"
 version = "0.0.0"
 dependencies = [
@@ -3700,6 +3718,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_index",
+ "rustc_parse",
  "rustc_target",
  "syntax",
  "syntax_pos",
@@ -3762,6 +3781,7 @@ dependencies = [
  "rustc",
  "rustc_codegen_utils",
  "rustc_data_structures",
+ "rustc_parse",
  "serde_json",
  "syntax",
  "syntax_pos",
@@ -4371,14 +4391,11 @@ dependencies = [
 name = "syntax_expand"
 version = "0.0.0"
 dependencies = [
- "bitflags",
- "lazy_static 1.3.0",
  "log",
  "rustc_data_structures",
  "rustc_errors",
- "rustc_index",
  "rustc_lexer",
- "scoped-tls",
+ "rustc_parse",
  "serialize",
  "smallvec 1.0.0",
  "syntax",
@@ -4393,6 +4410,7 @@ dependencies = [
  "log",
  "rustc_data_structures",
  "rustc_errors",
+ "rustc_parse",
  "rustc_target",
  "smallvec 1.0.0",
  "syntax",
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index a9e4e6db1c7..19726d6aff2 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -21,6 +21,7 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
+rustc_parse = { path = "../librustc_parse" }
 rustc_plugin = { path = "../librustc_plugin/deprecated" } # To get this in the sysroot
 rustc_plugin_impl = { path = "../librustc_plugin" }
 rustc_save_analysis = { path = "../librustc_save_analysis" }
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 611b891d99a..380cbed4b21 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -65,7 +65,6 @@ use std::time::Instant;
 use syntax::ast;
 use syntax::source_map::FileLoader;
 use syntax::feature_gate::{GatedCfg, UnstableFeatures};
-use syntax::parse;
 use syntax::symbol::sym;
 use syntax_pos::{DUMMY_SP, FileName};
 
@@ -1096,14 +1095,16 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
 }
 
 fn parse_crate_attrs<'a>(sess: &'a Session, input: &Input) -> PResult<'a, Vec<ast::Attribute>> {
-    match *input {
-        Input::File(ref ifile) => {
-            parse::parse_crate_attrs_from_file(ifile, &sess.parse_sess)
+    match input {
+        Input::File(ifile) => {
+            rustc_parse::parse_crate_attrs_from_file(ifile, &sess.parse_sess)
         }
-        Input::Str { ref name, ref input } => {
-            parse::parse_crate_attrs_from_source_str(name.clone(),
-                                                     input.clone(),
-                                                     &sess.parse_sess)
+        Input::Str { name, input } => {
+            rustc_parse::parse_crate_attrs_from_source_str(
+                name.clone(),
+                input.clone(),
+                &sess.parse_sess,
+            )
         }
     }
 }
diff --git a/src/librustc_interface/Cargo.toml b/src/librustc_interface/Cargo.toml
index 35b93db1d65..de59882bbdf 100644
--- a/src/librustc_interface/Cargo.toml
+++ b/src/librustc_interface/Cargo.toml
@@ -16,6 +16,7 @@ smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_expand = { path = "../libsyntax_expand" }
+rustc_parse = { path = "../librustc_parse" }
 syntax_pos = { path = "../libsyntax_pos" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 rustc = { path = "../librustc" }
diff --git a/src/librustc_interface/interface.rs b/src/librustc_interface/interface.rs
index 61f30392e06..02068b2ce38 100644
--- a/src/librustc_interface/interface.rs
+++ b/src/librustc_interface/interface.rs
@@ -11,11 +11,11 @@ use rustc_codegen_utils::codegen_backend::CodegenBackend;
 use rustc_data_structures::OnDrop;
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
+use rustc_parse::new_parser_from_source_str;
 use std::path::PathBuf;
 use std::result;
 use std::sync::{Arc, Mutex};
 use syntax::ast::{self, MetaItemKind};
-use syntax::parse::new_parser_from_source_str;
 use syntax::token;
 use syntax::source_map::{FileName, FileLoader, SourceMap};
 use syntax::sess::ParseSess;
diff --git a/src/librustc_interface/passes.rs b/src/librustc_interface/passes.rs
index c874e94124d..0e38de9a0ed 100644
--- a/src/librustc_interface/passes.rs
+++ b/src/librustc_interface/passes.rs
@@ -26,6 +26,7 @@ use rustc_errors::PResult;
 use rustc_incremental;
 use rustc_metadata::cstore;
 use rustc_mir as mir;
+use rustc_parse::{parse_crate_from_file, parse_crate_from_source_str};
 use rustc_passes::{self, ast_validation, hir_stats, layout_test};
 use rustc_plugin as plugin;
 use rustc_plugin::registry::Registry;
@@ -37,7 +38,6 @@ use syntax::{self, ast, visit};
 use syntax::early_buffered_lints::BufferedEarlyLint;
 use syntax_expand::base::{NamedSyntaxExtension, ExtCtxt};
 use syntax::mut_visit::MutVisitor;
-use syntax::parse;
 use syntax::util::node_count::NodeCounter;
 use syntax::symbol::Symbol;
 use syntax_pos::FileName;
@@ -60,12 +60,11 @@ pub fn parse<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::Crate> {
     let krate = time(sess, "parsing", || {
         let _prof_timer = sess.prof.generic_activity("parse_crate");
 
-        match *input {
-            Input::File(ref file) => parse::parse_crate_from_file(file, &sess.parse_sess),
-            Input::Str {
-                ref input,
-                ref name,
-            } => parse::parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess),
+        match input {
+            Input::File(file) => parse_crate_from_file(file, &sess.parse_sess),
+            Input::Str { input, name } => {
+                parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
+            }
         }
     })?;
 
@@ -484,7 +483,7 @@ pub fn lower_to_hir(
 ) -> Result<hir::map::Forest> {
     // Lower AST to HIR.
     let hir_forest = time(sess, "lowering AST -> HIR", || {
-        let nt_to_tokenstream = syntax::parse::nt_to_tokenstream;
+        let nt_to_tokenstream = rustc_parse::nt_to_tokenstream;
         let hir_crate = lower_crate(sess, &dep_graph, &krate, resolver, nt_to_tokenstream);
 
         if sess.opts.debugging_opts.hir_stats {
diff --git a/src/librustc_interface/util.rs b/src/librustc_interface/util.rs
index c02e5b9ae28..1cdb0ac87c5 100644
--- a/src/librustc_interface/util.rs
+++ b/src/librustc_interface/util.rs
@@ -50,6 +50,7 @@ pub fn diagnostics_registry() -> Registry {
     // FIXME: need to figure out a way to get these back in here
     // all_errors.extend_from_slice(get_codegen_backend(sess).diagnostics());
     all_errors.extend_from_slice(&rustc_metadata::error_codes::DIAGNOSTICS);
+    all_errors.extend_from_slice(&rustc_parse::error_codes::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_passes::error_codes::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_plugin::error_codes::DIAGNOSTICS);
     all_errors.extend_from_slice(&rustc_mir::error_codes::DIAGNOSTICS);
diff --git a/src/librustc_lexer/src/lib.rs b/src/librustc_lexer/src/lib.rs
index c50808adec1..3cecb4317b1 100644
--- a/src/librustc_lexer/src/lib.rs
+++ b/src/librustc_lexer/src/lib.rs
@@ -1,7 +1,7 @@
 //! Low-level Rust lexer.
 //!
 //! Tokens produced by this lexer are not yet ready for parsing the Rust syntax,
-//! for that see `libsyntax::parse::lexer`, which converts this basic token stream
+//! for that see `librustc_parse::lexer`, which converts this basic token stream
 //! into wide tokens used by actual parser.
 //!
 //! The purpose of this crate is to convert raw sources into a labeled sequence
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index 5bc047e001b..b1431563f21 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -23,4 +23,5 @@ rustc_serialize = { path = "../libserialize", package = "serialize" }
 stable_deref_trait = "1.0.0"
 syntax = { path = "../libsyntax" }
 syntax_expand = { path = "../libsyntax_expand" }
+rustc_parse = { path = "../librustc_parse" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
index 6eacfc28de2..19cfdeac57e 100644
--- a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
+++ b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
@@ -18,6 +18,8 @@ use rustc::hir::map::{DefKey, DefPath, DefPathHash};
 use rustc::hir::map::definitions::DefPathTable;
 use rustc::util::nodemap::DefIdMap;
 use rustc_data_structures::svh::Svh;
+use rustc_parse::source_file_to_stream;
+use rustc_parse::parser::emit_unclosed_delims;
 
 use smallvec::SmallVec;
 use std::any::Any;
@@ -27,8 +29,6 @@ use std::sync::Arc;
 use syntax::ast;
 use syntax::attr;
 use syntax::source_map;
-use syntax::parse::source_file_to_stream;
-use syntax::parse::parser::emit_unclosed_delims;
 use syntax::source_map::Spanned;
 use syntax::symbol::Symbol;
 use syntax_pos::{Span, FileName};
diff --git a/src/librustc_parse/Cargo.toml b/src/librustc_parse/Cargo.toml
new file mode 100644
index 00000000000..4579f9d472d
--- /dev/null
+++ b/src/librustc_parse/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "rustc_parse"
+version = "0.0.0"
+edition = "2018"
+
+[lib]
+name = "rustc_parse"
+path = "lib.rs"
+doctest = false
+
+[dependencies]
+bitflags = "1.0"
+log = "0.4"
+syntax_pos = { path = "../libsyntax_pos" }
+syntax = { path = "../libsyntax" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
+rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_lexer = { path = "../librustc_lexer" }
+rustc_target = { path = "../librustc_target" }
+smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/librustc_parse/error_codes.rs b/src/librustc_parse/error_codes.rs
new file mode 100644
index 00000000000..cf74e09a377
--- /dev/null
+++ b/src/librustc_parse/error_codes.rs
@@ -0,0 +1,174 @@
+// Error messages for EXXXX errors.
+// Each message should start and end with a new line, and be wrapped to 80
+// characters.  In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use
+// `:set tw=0` to disable.
+syntax::register_diagnostics! {
+
+E0178: r##"
+In types, the `+` type operator has low precedence, so it is often necessary
+to use parentheses.
+
+For example:
+
+```compile_fail,E0178
+trait Foo {}
+
+struct Bar<'a> {
+    w: &'a Foo + Copy,   // error, use &'a (Foo + Copy)
+    x: &'a Foo + 'a,     // error, use &'a (Foo + 'a)
+    y: &'a mut Foo + 'a, // error, use &'a mut (Foo + 'a)
+    z: fn() -> Foo + 'a, // error, use fn() -> (Foo + 'a)
+}
+```
+
+More details can be found in [RFC 438].
+
+[RFC 438]: https://github.com/rust-lang/rfcs/pull/438
+"##,
+
+E0583: r##"
+A file wasn't found for an out-of-line module.
+
+Erroneous code example:
+
+```ignore (compile_fail not working here; see Issue #43707)
+mod file_that_doesnt_exist; // error: file not found for module
+
+fn main() {}
+```
+
+Please be sure that a file corresponding to the module exists. If you
+want to use a module named `file_that_doesnt_exist`, you need to have a file
+named `file_that_doesnt_exist.rs` or `file_that_doesnt_exist/mod.rs` in the
+same directory.
+"##,
+
+E0584: r##"
+A doc comment that is not attached to anything has been encountered.
+
+Erroneous code example:
+
+```compile_fail,E0584
+trait Island {
+    fn lost();
+
+    /// I'm lost!
+}
+```
+
+A little reminder: a doc comment has to be placed before the item it's supposed
+to document. So if you want to document the `Island` trait, you need to put a
+doc comment before it, not inside it. Same goes for the `lost` method: the doc
+comment needs to be before it:
+
+```
+/// I'm THE island!
+trait Island {
+    /// I'm lost!
+    fn lost();
+}
+```
+"##,
+
+E0585: r##"
+A documentation comment that doesn't document anything was found.
+
+Erroneous code example:
+
+```compile_fail,E0585
+fn main() {
+    // The following doc comment will fail:
+    /// This is a useless doc comment!
+}
+```
+
+Documentation comments need to be followed by items, including functions,
+types, modules, etc. Examples:
+
+```
+/// I'm documenting the following struct:
+struct Foo;
+
+/// I'm documenting the following function:
+fn foo() {}
+```
+"##,
+
+E0586: r##"
+An inclusive range was used with no end.
+
+Erroneous code example:
+
+```compile_fail,E0586
+fn main() {
+    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
+    let x = &tmp[1..=]; // error: inclusive range was used with no end
+}
+```
+
+An inclusive range needs an end in order to *include* it. If you just need a
+start and no end, use a non-inclusive range (with `..`):
+
+```
+fn main() {
+    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
+    let x = &tmp[1..]; // ok!
+}
+```
+
+Or put an end to your inclusive range:
+
+```
+fn main() {
+    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
+    let x = &tmp[1..=3]; // ok!
+}
+```
+"##,
+
+E0704: r##"
+This error indicates that a incorrect visibility restriction was specified.
+
+Example of erroneous code:
+
+```compile_fail,E0704
+mod foo {
+    pub(foo) struct Bar {
+        x: i32
+    }
+}
+```
+
+To make struct `Bar` only visible in module `foo` the `in` keyword should be
+used:
+```
+mod foo {
+    pub(in crate::foo) struct Bar {
+        x: i32
+    }
+}
+# fn main() {}
+```
+
+For more information see the Rust Reference on [Visibility].
+
+[Visibility]: https://doc.rust-lang.org/reference/visibility-and-privacy.html
+"##,
+
+E0743: r##"
+C-variadic has been used on a non-foreign function.
+
+Erroneous code example:
+
+```compile_fail,E0743
+fn foo2(x: u8, ...) {} // error!
+```
+
+Only foreign functions can use C-variadic (`...`). It is used to give an
+undefined number of parameters to a given function (like `printf` in C). The
+equivalent in Rust would be to use macros directly.
+"##,
+
+;
+
+}
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/librustc_parse/lexer/mod.rs
index f2d5ff3440e..5de63cb39d1 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/librustc_parse/lexer/mod.rs
@@ -1,7 +1,7 @@
-use crate::token::{self, Token, TokenKind};
-use crate::sess::ParseSess;
-use crate::symbol::{sym, Symbol};
-use crate::util::comments;
+use syntax::token::{self, Token, TokenKind};
+use syntax::sess::ParseSess;
+use syntax::symbol::{sym, Symbol};
+use syntax::util::comments;
 
 use errors::{FatalError, DiagnosticBuilder};
 use syntax_pos::{BytePos, Pos, Span};
diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/librustc_parse/lexer/tokentrees.rs
index 2b056434d4d..1353591308b 100644
--- a/src/libsyntax/parse/lexer/tokentrees.rs
+++ b/src/librustc_parse/lexer/tokentrees.rs
@@ -3,9 +3,9 @@ use syntax_pos::Span;
 
 use super::{StringReader, UnmatchedBrace};
 
-use crate::print::pprust::token_to_string;
-use crate::token::{self, Token};
-use crate::tokenstream::{DelimSpan, IsJoint::{self, *}, TokenStream, TokenTree, TreeAndJoint};
+use syntax::print::pprust::token_to_string;
+use syntax::token::{self, Token};
+use syntax::tokenstream::{DelimSpan, IsJoint::{self, *}, TokenStream, TokenTree, TreeAndJoint};
 
 use errors::PResult;
 
diff --git a/src/libsyntax/parse/lexer/unescape_error_reporting.rs b/src/librustc_parse/lexer/unescape_error_reporting.rs
index 5565015179c..a5749d07e62 100644
--- a/src/libsyntax/parse/lexer/unescape_error_reporting.rs
+++ b/src/librustc_parse/lexer/unescape_error_reporting.rs
@@ -6,7 +6,7 @@ use std::iter::once;
 use rustc_lexer::unescape::{EscapeError, Mode};
 use syntax_pos::{Span, BytePos};
 
-use crate::errors::{Handler, Applicability};
+use syntax::errors::{Handler, Applicability};
 
 pub(crate) fn emit_unescape_error(
     handler: &Handler,
diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/librustc_parse/lexer/unicode_chars.rs
index 6eb995b61d3..6eb995b61d3 100644
--- a/src/libsyntax/parse/lexer/unicode_chars.rs
+++ b/src/librustc_parse/lexer/unicode_chars.rs
diff --git a/src/libsyntax/parse/mod.rs b/src/librustc_parse/lib.rs
index af3f8ecb45a..9f507d5319e 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/librustc_parse/lib.rs
@@ -1,11 +1,12 @@
 //! The main parser interface.
 
-use crate::ast;
-use crate::parse::parser::{Parser, emit_unclosed_delims, make_unclosed_delims_error};
-use crate::token::{self, Nonterminal};
-use crate::tokenstream::{self, TokenStream, TokenTree};
-use crate::print::pprust;
-use crate::sess::ParseSess;
+#![feature(crate_visibility_modifier)]
+
+use syntax::ast;
+use syntax::print::pprust;
+use syntax::sess::ParseSess;
+use syntax::token::{self, Nonterminal};
+use syntax::tokenstream::{self, TokenStream, TokenTree};
 
 use errors::{PResult, FatalError, Level, Diagnostic};
 use rustc_data_structures::sync::Lrc;
@@ -21,8 +22,10 @@ pub const MACRO_ARGUMENTS: Option<&'static str> = Some("macro arguments");
 
 #[macro_use]
 pub mod parser;
+use parser::{Parser, emit_unclosed_delims, make_unclosed_delims_error};
 pub mod lexer;
 pub mod validate_attr;
+pub mod error_codes;
 
 #[derive(Clone)]
 pub struct Directory<'a> {
diff --git a/src/libsyntax/parse/parser/attr.rs b/src/librustc_parse/parser/attr.rs
index 0f9e573af82..524b551e54c 100644
--- a/src/libsyntax/parse/parser/attr.rs
+++ b/src/librustc_parse/parser/attr.rs
@@ -1,12 +1,10 @@
 use super::{SeqSep, Parser, TokenType, PathStyle};
-use crate::attr;
-use crate::ast;
-use crate::util::comments;
-use crate::token::{self, Nonterminal, DelimToken};
-use crate::tokenstream::{TokenStream, TokenTree};
-use crate::source_map::Span;
-
-use syntax_pos::Symbol;
+use syntax::attr;
+use syntax::ast;
+use syntax::util::comments;
+use syntax::token::{self, Nonterminal, DelimToken};
+use syntax::tokenstream::{TokenStream, TokenTree};
+use syntax_pos::{Span, Symbol};
 use errors::PResult;
 
 use log::debug;
@@ -158,12 +156,7 @@ impl<'a> Parser<'a> {
             }
         };
 
-        Ok(ast::Attribute {
-            kind: ast::AttrKind::Normal(item),
-            id: attr::mk_attr_id(),
-            style,
-            span,
-        })
+        Ok(attr::mk_attr_from_item(style, item, span))
     }
 
     /// Parses an inner part of an attribute (the path and following tokens).
diff --git a/src/libsyntax/parse/parser/diagnostics.rs b/src/librustc_parse/parser/diagnostics.rs
index 5df24804a76..38eae008537 100644
--- a/src/libsyntax/parse/parser/diagnostics.rs
+++ b/src/librustc_parse/parser/diagnostics.rs
@@ -1,14 +1,16 @@
 use super::{BlockMode, PathStyle, SemiColonMode, TokenType, TokenExpectType, SeqSep, Parser};
-use crate::ast::{
+
+use syntax::ast::{
     self, Param, BinOpKind, BindingMode, BlockCheckMode, Expr, ExprKind, Ident, Item, ItemKind,
     Mutability, Pat, PatKind, PathSegment, QSelf, Ty, TyKind,
 };
-use crate::token::{self, TokenKind, token_can_begin_expr};
-use crate::print::pprust;
-use crate::ptr::P;
-use crate::symbol::{kw, sym};
-use crate::ThinVec;
-use crate::util::parser::AssocOp;
+use syntax::token::{self, TokenKind, token_can_begin_expr};
+use syntax::print::pprust;
+use syntax::ptr::P;
+use syntax::symbol::{kw, sym};
+use syntax::ThinVec;
+use syntax::util::parser::AssocOp;
+use syntax::struct_span_err;
 
 use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, pluralize};
 use rustc_data_structures::fx::FxHashSet;
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index 800074035ce..dadb91f8b3c 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -2,24 +2,23 @@ use super::{Parser, Restrictions, PrevTokenKind, TokenType, PathStyle, BlockMode
 use super::{SemiColonMode, SeqSep, TokenExpectType};
 use super::pat::{GateOr, PARAM_EXPECTED};
 use super::diagnostics::Error;
+use crate::maybe_recover_from_interpolated_ty_qpath;
 
-use crate::ast::{
+use syntax::ast::{
     self, DUMMY_NODE_ID, Attribute, AttrStyle, Ident, CaptureBy, BlockCheckMode,
     Expr, ExprKind, RangeLimits, Label, Movability, IsAsync, Arm, Ty, TyKind,
     FunctionRetTy, Param, FnDecl, BinOpKind, BinOp, UnOp, Mac, AnonConst, Field, Lit,
 };
-use crate::maybe_recover_from_interpolated_ty_qpath;
-use crate::token::{self, Token, TokenKind};
-use crate::print::pprust;
-use crate::ptr::P;
-use crate::source_map::{self, Span};
-use crate::util::classify;
-use crate::util::literal::LitError;
-use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par};
-
-use errors::{PResult, Applicability};
+use syntax::token::{self, Token, TokenKind};
+use syntax::print::pprust;
+use syntax::ptr::P;
+use syntax::source_map::{self, Span};
+use syntax::util::classify;
+use syntax::util::literal::LitError;
+use syntax::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par};
 use syntax_pos::symbol::{kw, sym};
 use syntax_pos::Symbol;
+use errors::{PResult, Applicability};
 use std::mem;
 use rustc_data_structures::thin_vec::ThinVec;
 
diff --git a/src/libsyntax/parse/parser/generics.rs b/src/librustc_parse/parser/generics.rs
index ae9ecd8fe39..ba5eafc0ed7 100644
--- a/src/libsyntax/parse/parser/generics.rs
+++ b/src/librustc_parse/parser/generics.rs
@@ -1,9 +1,8 @@
 use super::Parser;
 
-use crate::ast::{self, WhereClause, GenericParam, GenericParamKind, GenericBounds, Attribute};
-use crate::token;
-use crate::source_map::DUMMY_SP;
-
+use syntax::ast::{self, WhereClause, GenericParam, GenericParamKind, GenericBounds, Attribute};
+use syntax::token;
+use syntax::source_map::DUMMY_SP;
 use syntax_pos::symbol::{kw, sym};
 
 use errors::PResult;
diff --git a/src/libsyntax/parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 531ad532a54..3e21436d313 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -2,23 +2,24 @@ use super::{Parser, PathStyle};
 use super::diagnostics::{Error, dummy_arg, ConsumeClosingDelim};
 
 use crate::maybe_whole;
-use crate::ptr::P;
-use crate::ast::{self, Abi, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, AnonConst, Item};
-use crate::ast::{ItemKind, ImplItem, ImplItemKind, TraitItem, TraitItemKind, UseTree, UseTreeKind};
-use crate::ast::{PathSegment, IsAuto, Constness, IsAsync, Unsafety, Defaultness};
-use crate::ast::{Visibility, VisibilityKind, Mutability, FnHeader, ForeignItem, ForeignItemKind};
-use crate::ast::{Ty, TyKind, Generics, GenericBounds, TraitRef, EnumDef, VariantData, StructField};
-use crate::ast::{Mac, MacDelimiter, Block, BindingMode, FnDecl, FnSig, SelfKind, Param};
-use crate::parse::token;
-use crate::tokenstream::{TokenTree, TokenStream};
-use crate::symbol::{kw, sym};
-use crate::source_map::{self, respan, Span};
-use crate::ThinVec;
+
+use syntax::ast::{self, Abi, DUMMY_NODE_ID, Ident, Attribute, AttrKind, AttrStyle, AnonConst, Item};
+use syntax::ast::{ItemKind, ImplItem, ImplItemKind, TraitItem, TraitItemKind, UseTree, UseTreeKind};
+use syntax::ast::{PathSegment, IsAuto, Constness, IsAsync, Unsafety, Defaultness};
+use syntax::ast::{Visibility, VisibilityKind, Mutability, FnHeader, ForeignItem, ForeignItemKind};
+use syntax::ast::{Ty, TyKind, Generics, GenericBounds, TraitRef, EnumDef, VariantData, StructField};
+use syntax::ast::{Mac, MacDelimiter, Block, BindingMode, FnDecl, FnSig, SelfKind, Param};
+use syntax::ptr::P;
+use syntax::ThinVec;
+use syntax::token;
+use syntax::tokenstream::{TokenTree, TokenStream};
+use syntax::source_map::{self, respan, Span};
+use syntax_pos::BytePos;
+use syntax_pos::symbol::{kw, sym};
 
 use log::debug;
 use std::mem;
 use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, StashKey};
-use syntax_pos::BytePos;
 
 /// Whether the type alias or associated type is a concrete type or an opaque type.
 #[derive(Debug)]
diff --git a/src/libsyntax/parse/parser/mod.rs b/src/librustc_parse/parser/mod.rs
index 455f4172f5f..a491d91e20f 100644
--- a/src/libsyntax/parse/parser/mod.rs
+++ b/src/librustc_parse/parser/mod.rs
@@ -11,24 +11,26 @@ mod generics;
 mod diagnostics;
 use diagnostics::Error;
 
-use crate::ast::{
+use crate::{Directory, DirectoryOwnership};
+use crate::lexer::UnmatchedBrace;
+
+use syntax::ast::{
     self, Abi, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
     IsAsync, MacDelimiter, Mutability, StrStyle, Visibility, VisibilityKind, Unsafety,
 };
-use crate::parse::{Directory, DirectoryOwnership};
-use crate::parse::lexer::UnmatchedBrace;
-use crate::util::comments::{doc_comment_style, strip_doc_comment_decoration};
-use crate::token::{self, Token, TokenKind, DelimToken};
-use crate::print::pprust;
-use crate::ptr::P;
-use crate::sess::ParseSess;
-use crate::source_map::respan;
-use crate::symbol::{kw, sym, Symbol};
-use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
-use crate::ThinVec;
 
-use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
+use syntax::print::pprust;
+use syntax::ptr::P;
+use syntax::token::{self, Token, TokenKind, DelimToken};
+use syntax::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
+use syntax::sess::ParseSess;
+use syntax::source_map::respan;
+use syntax::struct_span_err;
+use syntax::util::comments::{doc_comment_style, strip_doc_comment_decoration};
+use syntax_pos::symbol::{kw, sym, Symbol};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
+use rustc_data_structures::thin_vec::ThinVec;
+use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
 use log::debug;
 
 use std::borrow::Cow;
diff --git a/src/libsyntax/parse/parser/module.rs b/src/librustc_parse/parser/module.rs
index ad72b3a1dea..3110f15e80b 100644
--- a/src/libsyntax/parse/parser/module.rs
+++ b/src/librustc_parse/parser/module.rs
@@ -2,11 +2,12 @@ use super::Parser;
 use super::item::ItemInfo;
 use super::diagnostics::Error;
 
-use crate::attr;
-use crate::ast::{self, Ident, Attribute, ItemKind, Mod, Crate};
-use crate::parse::{new_sub_parser_from_file, DirectoryOwnership};
-use crate::token::{self, TokenKind};
-use crate::source_map::{SourceMap, Span, DUMMY_SP, FileName};
+use crate::{new_sub_parser_from_file, DirectoryOwnership};
+
+use syntax::attr;
+use syntax::ast::{self, Ident, Attribute, ItemKind, Mod, Crate};
+use syntax::token::{self, TokenKind};
+use syntax::source_map::{SourceMap, Span, DUMMY_SP, FileName};
 
 use syntax_pos::symbol::sym;
 use errors::PResult;
diff --git a/src/libsyntax/parse/parser/pat.rs b/src/librustc_parse/parser/pat.rs
index f347300da71..b068a4f16a5 100644
--- a/src/libsyntax/parse/parser/pat.rs
+++ b/src/librustc_parse/parser/pat.rs
@@ -1,14 +1,13 @@
 use super::{Parser, PathStyle};
-
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
-use crate::ptr::P;
-use crate::ast::{self, Attribute, Pat, PatKind, FieldPat, RangeEnd, RangeSyntax, Mac};
-use crate::ast::{BindingMode, Ident, Mutability, Path, QSelf, Expr, ExprKind};
-use crate::mut_visit::{noop_visit_pat, noop_visit_mac, MutVisitor};
-use crate::token;
-use crate::print::pprust;
-use crate::source_map::{respan, Span, Spanned};
-use crate::ThinVec;
+use syntax::ast::{self, Attribute, Pat, PatKind, FieldPat, RangeEnd, RangeSyntax, Mac};
+use syntax::ast::{BindingMode, Ident, Mutability, Path, QSelf, Expr, ExprKind};
+use syntax::mut_visit::{noop_visit_pat, noop_visit_mac, MutVisitor};
+use syntax::ptr::P;
+use syntax::print::pprust;
+use syntax::ThinVec;
+use syntax::token;
+use syntax::source_map::{respan, Span, Spanned};
 use syntax_pos::symbol::{kw, sym};
 use errors::{PResult, Applicability, DiagnosticBuilder};
 
diff --git a/src/libsyntax/parse/parser/path.rs b/src/librustc_parse/parser/path.rs
index 9ceb3ba1eb4..68307440712 100644
--- a/src/libsyntax/parse/parser/path.rs
+++ b/src/librustc_parse/parser/path.rs
@@ -1,10 +1,10 @@
 use super::{Parser, TokenType};
-
-use crate::{maybe_whole, ThinVec};
-use crate::ast::{self, QSelf, Path, PathSegment, Ident, ParenthesizedArgs, AngleBracketedArgs};
-use crate::ast::{AnonConst, GenericArg, AssocTyConstraint, AssocTyConstraintKind, BlockCheckMode};
-use crate::token::{self, Token};
-use crate::source_map::{Span, BytePos};
+use crate::maybe_whole;
+use syntax::ast::{self, QSelf, Path, PathSegment, Ident, ParenthesizedArgs, AngleBracketedArgs};
+use syntax::ast::{AnonConst, GenericArg, AssocTyConstraint, AssocTyConstraintKind, BlockCheckMode};
+use syntax::ThinVec;
+use syntax::token::{self, Token};
+use syntax::source_map::{Span, BytePos};
 use syntax_pos::symbol::{kw, sym};
 
 use std::mem;
diff --git a/src/libsyntax/parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 30e47b7a0b2..a5f20691d07 100644
--- a/src/libsyntax/parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -3,16 +3,18 @@ use super::expr::LhsExpr;
 use super::path::PathStyle;
 use super::pat::GateOr;
 use super::diagnostics::Error;
-
-use crate::ptr::P;
-use crate::{maybe_whole, ThinVec};
-use crate::ast::{self, DUMMY_NODE_ID, Stmt, StmtKind, Local, Block, BlockCheckMode, Expr, ExprKind};
-use crate::ast::{Attribute, AttrStyle, VisibilityKind, MacStmtStyle, Mac, MacDelimiter};
-use crate::parse::DirectoryOwnership;
-use crate::util::classify;
-use crate::token;
-use crate::source_map::{respan, Span};
-use crate::symbol::{kw, sym};
+use crate::maybe_whole;
+use crate::DirectoryOwnership;
+
+use syntax::ThinVec;
+use syntax::ptr::P;
+use syntax::ast;
+use syntax::ast::{DUMMY_NODE_ID, Stmt, StmtKind, Local, Block, BlockCheckMode, Expr, ExprKind};
+use syntax::ast::{Attribute, AttrStyle, VisibilityKind, MacStmtStyle, Mac, MacDelimiter};
+use syntax::util::classify;
+use syntax::token;
+use syntax::source_map::{respan, Span};
+use syntax::symbol::{kw, sym};
 
 use std::mem;
 use errors::{PResult, Applicability};
diff --git a/src/libsyntax/parse/parser/ty.rs b/src/librustc_parse/parser/ty.rs
index a891634e611..fccabee2404 100644
--- a/src/libsyntax/parse/parser/ty.rs
+++ b/src/librustc_parse/parser/ty.rs
@@ -2,13 +2,15 @@ use super::{Parser, PathStyle, PrevTokenKind, TokenType};
 use super::item::ParamCfg;
 
 use crate::{maybe_whole, maybe_recover_from_interpolated_ty_qpath};
-use crate::ptr::P;
-use crate::ast::{self, Ty, TyKind, MutTy, BareFnTy, FunctionRetTy, GenericParam, Lifetime, Ident};
-use crate::ast::{TraitBoundModifier, TraitObjectSyntax, GenericBound, GenericBounds, PolyTraitRef};
-use crate::ast::{Mutability, AnonConst, Mac};
-use crate::token::{self, Token};
-use crate::source_map::Span;
-use crate::symbol::{kw};
+
+use syntax::ptr::P;
+use syntax::ast::{self, Ty, TyKind, MutTy, BareFnTy, FunctionRetTy, GenericParam, Lifetime, Ident};
+use syntax::ast::{TraitBoundModifier, TraitObjectSyntax, GenericBound, GenericBounds, PolyTraitRef};
+use syntax::ast::{Mutability, AnonConst, Mac};
+use syntax::token::{self, Token};
+use syntax::source_map::Span;
+use syntax::struct_span_fatal;
+use syntax_pos::symbol::kw;
 
 use errors::{PResult, Applicability, pluralize};
 
diff --git a/src/libsyntax/parse/validate_attr.rs b/src/librustc_parse/validate_attr.rs
index 6cc8a1ec33e..bbe0dc1c35f 100644
--- a/src/libsyntax/parse/validate_attr.rs
+++ b/src/librustc_parse/validate_attr.rs
@@ -1,14 +1,13 @@
 //! Meta-syntax validation logic of attributes for post-expansion.
 
-use crate::ast::{self, Attribute, AttrKind, Ident, MetaItem};
-use crate::attr::{AttributeTemplate, mk_name_value_item_str};
-use crate::sess::ParseSess;
-use crate::feature_gate::BUILTIN_ATTRIBUTE_MAP;
-use crate::early_buffered_lints::BufferedEarlyLintId;
-use crate::token;
-use crate::tokenstream::TokenTree;
-
 use errors::{PResult, Applicability};
+use syntax::ast::{self, Attribute, AttrKind, Ident, MetaItem};
+use syntax::attr::{AttributeTemplate, mk_name_value_item_str};
+use syntax::early_buffered_lints::BufferedEarlyLintId;
+use syntax::feature_gate::BUILTIN_ATTRIBUTE_MAP;
+use syntax::token;
+use syntax::tokenstream::TokenTree;
+use syntax::sess::ParseSess;
 use syntax_pos::{Symbol, sym};
 
 pub fn check_meta(sess: &ParseSess, attr: &Attribute) {
diff --git a/src/librustc_passes/Cargo.toml b/src/librustc_passes/Cargo.toml
index 9d29a230314..556189208f1 100644
--- a/src/librustc_passes/Cargo.toml
+++ b/src/librustc_passes/Cargo.toml
@@ -12,8 +12,9 @@ path = "lib.rs"
 log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_index = { path = "../librustc_index" }
+rustc_parse = { path = "../librustc_parse" }
+rustc_target = { path = "../librustc_target" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
-rustc_target = { path = "../librustc_target" }
-rustc_index = { path = "../librustc_index" }
diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs
index a45035f123f..ec5572914d8 100644
--- a/src/librustc_passes/ast_validation.rs
+++ b/src/librustc_passes/ast_validation.rs
@@ -7,15 +7,15 @@
 // or type checking or some other kind of complex analysis.
 
 use std::mem;
-use syntax::print::pprust;
 use rustc::lint;
 use rustc::session::Session;
 use rustc_data_structures::fx::FxHashMap;
+use rustc_parse::validate_attr;
 use syntax::ast::*;
 use syntax::attr;
 use syntax::expand::is_proc_macro_attr;
 use syntax::feature_gate::is_builtin_attr;
-use syntax::parse::validate_attr;
+use syntax::print::pprust;
 use syntax::source_map::Spanned;
 use syntax::symbol::{kw, sym};
 use syntax::visit::{self, Visitor};
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index 2d93585e50e..50b3be6dca1 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -13,6 +13,7 @@ log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_codegen_utils = { path = "../librustc_codegen_utils" }
+rustc_parse = { path = "../librustc_parse" }
 serde_json = "1"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_save_analysis/span_utils.rs b/src/librustc_save_analysis/span_utils.rs
index 4d0780cf94d..f2f512bc8e5 100644
--- a/src/librustc_save_analysis/span_utils.rs
+++ b/src/librustc_save_analysis/span_utils.rs
@@ -1,8 +1,6 @@
-use rustc::session::Session;
-
 use crate::generated_code;
-
-use syntax::parse::lexer::{self, StringReader};
+use rustc::session::Session;
+use rustc_parse::lexer::{self, StringReader};
 use syntax::token::{self, TokenKind};
 use syntax_pos::*;
 
diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
index 71a44c0ebdb..bf4a1440e1b 100644
--- a/src/librustdoc/html/highlight.rs
+++ b/src/librustdoc/html/highlight.rs
@@ -11,10 +11,10 @@ use std::fmt::Display;
 use std::io;
 use std::io::prelude::*;
 
-use syntax::source_map::SourceMap;
-use syntax::parse::lexer;
+use rustc_parse::lexer;
 use syntax::token::{self, Token};
 use syntax::sess::ParseSess;
+use syntax::source_map::SourceMap;
 use syntax::symbol::{kw, sym};
 use syntax_expand::config::process_configure_mod;
 use syntax_pos::{Span, FileName};
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 13b8809e23e..86e0f22db50 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -29,6 +29,7 @@ extern crate rustc_resolve;
 extern crate rustc_lint;
 extern crate rustc_interface;
 extern crate rustc_metadata;
+extern crate rustc_parse;
 extern crate rustc_target;
 extern crate rustc_typeck;
 extern crate rustc_lexer;
diff --git a/src/librustdoc/passes/check_code_block_syntax.rs b/src/librustdoc/passes/check_code_block_syntax.rs
index 405f3a70e0e..5c4c975cec0 100644
--- a/src/librustdoc/passes/check_code_block_syntax.rs
+++ b/src/librustdoc/passes/check_code_block_syntax.rs
@@ -1,5 +1,5 @@
 use errors::Applicability;
-use syntax::parse::lexer::{StringReader as Lexer};
+use rustc_parse::lexer::{StringReader as Lexer};
 use syntax::token;
 use syntax::sess::ParseSess;
 use syntax::source_map::FilePathMapping;
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index e4cf1bb0bb9..553ef6a9c47 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -399,7 +399,8 @@ pub fn make_test(s: &str,
     // Uses libsyntax to parse the doctest and find if there's a main fn and the extern
     // crate already is included.
     let (already_has_main, already_has_extern_crate, found_macro) = with_globals(edition, || {
-        use crate::syntax::{parse, sess::ParseSess, source_map::FilePathMapping};
+        use crate::syntax::{sess::ParseSess, source_map::FilePathMapping};
+        use rustc_parse::maybe_new_parser_from_source_str;
         use errors::emitter::EmitterWriter;
         use errors::Handler;
 
@@ -418,7 +419,7 @@ pub fn make_test(s: &str,
         let mut found_extern_crate = cratename.is_none();
         let mut found_macro = false;
 
-        let mut parser = match parse::maybe_new_parser_from_source_str(&sess, filename, source) {
+        let mut parser = match maybe_new_parser_from_source_str(&sess, filename, source) {
             Ok(p) => p,
             Err(errs) => {
                 for mut err in errs {
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index b57d2238991..170d089d4bb 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -537,7 +537,7 @@ pub struct Pat {
 impl Pat {
     /// Attempt reparsing the pattern as a type.
     /// This is intended for use by diagnostics.
-    pub(super) fn to_ty(&self) -> Option<P<Ty>> {
+    pub fn to_ty(&self) -> Option<P<Ty>> {
         let kind = match &self.kind {
             // In a type expression `_` is an inference variable.
             PatKind::Wild => TyKind::Infer,
@@ -1031,7 +1031,7 @@ impl Expr {
         }
     }
 
-    fn to_bound(&self) -> Option<GenericBound> {
+    pub fn to_bound(&self) -> Option<GenericBound> {
         match &self.kind {
             ExprKind::Path(None, path) => Some(GenericBound::Trait(
                 PolyTraitRef::new(Vec::new(), path.clone(), self.span),
@@ -1042,7 +1042,7 @@ impl Expr {
     }
 
     /// Attempts to reparse as `Ty` (for diagnostic purposes).
-    pub(super) fn to_ty(&self) -> Option<P<Ty>> {
+    pub fn to_ty(&self) -> Option<P<Ty>> {
         let kind = match &self.kind {
             // Trivial conversions.
             ExprKind::Path(qself, path) => TyKind::Path(qself.clone(), path.clone()),
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index 3ac9abb7223..d0a31b330ab 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -24,9 +24,9 @@ enum AttrError {
 /// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now.
 #[derive(Clone, Copy)]
 pub struct AttributeTemplate {
-    crate word: bool,
-    crate list: Option<&'static str>,
-    crate name_value_str: Option<&'static str>,
+    pub word: bool,
+    pub list: Option<&'static str>,
+    pub name_value_str: Option<&'static str>,
 }
 
 impl AttributeTemplate {
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index d458549e298..29eff5c2981 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -277,7 +277,7 @@ impl MetaItem {
 }
 
 impl AttrItem {
-    crate fn meta(&self, span: Span) -> Option<MetaItem> {
+    pub fn meta(&self, span: Span) -> Option<MetaItem> {
         let mut tokens = self.tokens.trees().peekable();
         Some(MetaItem {
             path: self.path.clone(),
diff --git a/src/libsyntax/error_codes.rs b/src/libsyntax/error_codes.rs
index c23c8d65a7f..0e81de7d4a7 100644
--- a/src/libsyntax/error_codes.rs
+++ b/src/libsyntax/error_codes.rs
@@ -4,28 +4,6 @@
 // `:set tw=0` to disable.
 register_diagnostics! {
 
-E0178: r##"
-In types, the `+` type operator has low precedence, so it is often necessary
-to use parentheses.
-
-For example:
-
-```compile_fail,E0178
-trait Foo {}
-
-struct Bar<'a> {
-    w: &'a Foo + Copy,   // error, use &'a (Foo + Copy)
-    x: &'a Foo + 'a,     // error, use &'a (Foo + 'a)
-    y: &'a mut Foo + 'a, // error, use &'a mut (Foo + 'a)
-    z: fn() -> Foo + 'a, // error, use fn() -> (Foo + 'a)
-}
-```
-
-More details can be found in [RFC 438].
-
-[RFC 438]: https://github.com/rust-lang/rfcs/pull/438
-"##,
-
 E0536: r##"
 The `not` cfg-predicate was malformed.
 
@@ -278,106 +256,6 @@ pub fn something() {}
 ```
 "##,
 
-E0583: r##"
-A file wasn't found for an out-of-line module.
-
-Erroneous code example:
-
-```ignore (compile_fail not working here; see Issue #43707)
-mod file_that_doesnt_exist; // error: file not found for module
-
-fn main() {}
-```
-
-Please be sure that a file corresponding to the module exists. If you
-want to use a module named `file_that_doesnt_exist`, you need to have a file
-named `file_that_doesnt_exist.rs` or `file_that_doesnt_exist/mod.rs` in the
-same directory.
-"##,
-
-E0584: r##"
-A doc comment that is not attached to anything has been encountered.
-
-Erroneous code example:
-
-```compile_fail,E0584
-trait Island {
-    fn lost();
-
-    /// I'm lost!
-}
-```
-
-A little reminder: a doc comment has to be placed before the item it's supposed
-to document. So if you want to document the `Island` trait, you need to put a
-doc comment before it, not inside it. Same goes for the `lost` method: the doc
-comment needs to be before it:
-
-```
-/// I'm THE island!
-trait Island {
-    /// I'm lost!
-    fn lost();
-}
-```
-"##,
-
-E0585: r##"
-A documentation comment that doesn't document anything was found.
-
-Erroneous code example:
-
-```compile_fail,E0585
-fn main() {
-    // The following doc comment will fail:
-    /// This is a useless doc comment!
-}
-```
-
-Documentation comments need to be followed by items, including functions,
-types, modules, etc. Examples:
-
-```
-/// I'm documenting the following struct:
-struct Foo;
-
-/// I'm documenting the following function:
-fn foo() {}
-```
-"##,
-
-E0586: r##"
-An inclusive range was used with no end.
-
-Erroneous code example:
-
-```compile_fail,E0586
-fn main() {
-    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
-    let x = &tmp[1..=]; // error: inclusive range was used with no end
-}
-```
-
-An inclusive range needs an end in order to *include* it. If you just need a
-start and no end, use a non-inclusive range (with `..`):
-
-```
-fn main() {
-    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
-    let x = &tmp[1..]; // ok!
-}
-```
-
-Or put an end to your inclusive range:
-
-```
-fn main() {
-    let tmp = vec![0, 1, 2, 3, 4, 4, 3, 3, 2, 1];
-    let x = &tmp[1..=3]; // ok!
-}
-```
-"##,
-
 E0589: r##"
 The value of `N` that was specified for `repr(align(N))` was not a power
 of two, or was greater than 2^29.
@@ -446,35 +324,6 @@ and likely to change in the future.
 
 "##,
 
-E0704: r##"
-This error indicates that a incorrect visibility restriction was specified.
-
-Example of erroneous code:
-
-```compile_fail,E0704
-mod foo {
-    pub(foo) struct Bar {
-        x: i32
-    }
-}
-```
-
-To make struct `Bar` only visible in module `foo` the `in` keyword should be
-used:
-```
-mod foo {
-    pub(in crate::foo) struct Bar {
-        x: i32
-    }
-}
-# fn main() {}
-```
-
-For more information see the Rust Reference on [Visibility].
-
-[Visibility]: https://doc.rust-lang.org/reference/visibility-and-privacy.html
-"##,
-
 E0705: r##"
 A `#![feature]` attribute was declared for a feature that is stable in
 the current edition, but not in all editions.
@@ -504,20 +353,6 @@ Delete the offending feature attribute, or add it to the list of allowed
 features in the `-Z allow_features` flag.
 "##,
 
-E0743: r##"
-C-variadic has been used on a non-foreign function.
-
-Erroneous code example:
-
-```compile_fail,E0743
-fn foo2(x: u8, ...) {} // error!
-```
-
-Only foreign functions can use C-variadic (`...`). It is used to give an
-undefined number of parameters to a given function (like `printf` in C). The
-equivalent in Rust would be to use macros directly.
-"##,
-
 ;
 
     E0539, // incorrect meta item
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 7fecc87a18f..317fcf29389 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -26,8 +26,6 @@ pub use rustc_data_structures::thin_vec::ThinVec;
 use ast::AttrId;
 use syntax_pos::edition::Edition;
 
-pub const MACRO_ARGUMENTS: Option<&'static str> = Some("macro arguments");
-
 #[macro_export]
 macro_rules! unwrap_or {
     ($opt:expr, $default:expr) => {
@@ -82,10 +80,10 @@ pub mod diagnostics {
 pub mod error_codes;
 
 pub mod util {
-    crate mod classify;
+    pub mod classify;
     pub mod comments;
     pub mod lev_distance;
-    crate mod literal;
+    pub mod literal;
     pub mod node_count;
     pub mod parser;
     pub mod map_in_place;
@@ -100,7 +98,6 @@ pub mod source_map;
 pub mod entry;
 pub mod feature_gate;
 pub mod mut_visit;
-pub mod parse;
 pub mod ptr;
 pub mod show_span;
 pub use syntax_pos::edition;
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 04f096200b8..f154b7bde98 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -321,7 +321,7 @@ fn token_to_string_ext(token: &Token, convert_dollar_crate: bool) -> String {
     token_kind_to_string_ext(&token.kind, convert_dollar_crate)
 }
 
-crate fn nonterminal_to_string(nt: &Nonterminal) -> String {
+pub fn nonterminal_to_string(nt: &Nonterminal) -> String {
     match *nt {
         token::NtExpr(ref e)        => expr_to_string(e),
         token::NtMeta(ref e)        => attr_item_to_string(e),
@@ -958,7 +958,7 @@ impl<'a> State<'a> {
         }
     }
 
-    crate fn print_opt_lifetime(&mut self, lifetime: &Option<ast::Lifetime>) {
+    pub fn print_opt_lifetime(&mut self, lifetime: &Option<ast::Lifetime>) {
         if let Some(lt) = *lifetime {
             self.print_lifetime(lt);
             self.nbsp();
@@ -973,7 +973,7 @@ impl<'a> State<'a> {
         }
     }
 
-    crate fn print_type(&mut self, ty: &ast::Ty) {
+    pub fn print_type(&mut self, ty: &ast::Ty) {
         self.maybe_print_comment(ty.span.lo());
         self.ibox(0);
         match ty.kind {
@@ -1998,7 +1998,7 @@ impl<'a> State<'a> {
         self.print_expr_maybe_paren(expr, parser::PREC_PREFIX)
     }
 
-    crate fn print_expr(&mut self, expr: &ast::Expr) {
+    pub fn print_expr(&mut self, expr: &ast::Expr) {
         self.print_expr_outer_attr_style(expr, true)
     }
 
@@ -2335,7 +2335,7 @@ impl<'a> State<'a> {
         }
     }
 
-    crate fn print_usize(&mut self, i: usize) {
+    pub fn print_usize(&mut self, i: usize) {
         self.s.word(i.to_string())
     }
 
@@ -2604,7 +2604,7 @@ impl<'a> State<'a> {
         }
     }
 
-    crate fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
+    pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
         if !bounds.is_empty() {
             self.s.word(prefix);
             let mut first = true;
@@ -2763,7 +2763,7 @@ impl<'a> State<'a> {
         }
     }
 
-    crate fn print_mutability(&mut self, mutbl: ast::Mutability) {
+    pub fn print_mutability(&mut self, mutbl: ast::Mutability) {
         match mutbl {
             ast::Mutability::Mutable => self.word_nbsp("mut"),
             ast::Mutability::Immutable => {},
diff --git a/src/libsyntax/sess.rs b/src/libsyntax/sess.rs
index 5e96b27c970..953f0d1d190 100644
--- a/src/libsyntax/sess.rs
+++ b/src/libsyntax/sess.rs
@@ -71,14 +71,14 @@ impl GatedSpans {
 /// Info about a parsing session.
 pub struct ParseSess {
     pub span_diagnostic: Handler,
-    crate unstable_features: UnstableFeatures,
+    pub unstable_features: UnstableFeatures,
     pub config: CrateConfig,
     pub edition: Edition,
     pub missing_fragment_specifiers: Lock<FxHashSet<Span>>,
     /// Places where raw identifiers were used. This is used for feature-gating raw identifiers.
     pub raw_identifier_spans: Lock<Vec<Span>>,
     /// Used to determine and report recursive module inclusions.
-    pub(super) included_mod_stack: Lock<Vec<PathBuf>>,
+    pub included_mod_stack: Lock<Vec<PathBuf>>,
     source_map: Lrc<SourceMap>,
     pub buffered_lints: Lock<Vec<BufferedEarlyLint>>,
     /// Contains the spans of block expressions that could have been incomplete based on the
diff --git a/src/libsyntax/token.rs b/src/libsyntax/token.rs
index 6f3da344ccf..c70e3442703 100644
--- a/src/libsyntax/token.rs
+++ b/src/libsyntax/token.rs
@@ -107,14 +107,14 @@ impl fmt::Display for Lit {
 
 impl LitKind {
     /// An English article for the literal token kind.
-    crate fn article(self) -> &'static str {
+    pub fn article(self) -> &'static str {
         match self {
             Integer | Err => "an",
             _ => "a",
         }
     }
 
-    crate fn descr(self) -> &'static str {
+    pub fn descr(self) -> &'static str {
         match self {
             Bool => panic!("literal token contains `Lit::Bool`"),
             Byte => "byte",
@@ -141,12 +141,12 @@ impl Lit {
     }
 }
 
-pub(crate) fn ident_can_begin_expr(name: ast::Name, span: Span, is_raw: bool) -> bool {
+pub fn ident_can_begin_expr(name: ast::Name, span: Span, is_raw: bool) -> bool {
     let ident_token = Token::new(Ident(name, is_raw), span);
     token_can_begin_expr(&ident_token)
 }
 
-pub(crate) fn token_can_begin_expr(ident_token: &Token) -> bool {
+pub fn token_can_begin_expr(ident_token: &Token) -> bool {
     !ident_token.is_reserved_ident() ||
     ident_token.is_path_segment_keyword() ||
     match ident_token.kind {
@@ -276,7 +276,7 @@ impl TokenKind {
 
     /// Returns tokens that are likely to be typed accidentally instead of the current token.
     /// Enables better error recovery when the wrong token is found.
-    crate fn similar_tokens(&self) -> Option<Vec<TokenKind>> {
+    pub fn similar_tokens(&self) -> Option<Vec<TokenKind>> {
         match *self {
             Comma => Some(vec![Dot, Lt, Semi]),
             Semi => Some(vec![Colon, Comma]),
@@ -291,7 +291,7 @@ impl Token {
     }
 
     /// Some token that will be thrown away later.
-    crate fn dummy() -> Self {
+    pub fn dummy() -> Self {
         Token::new(TokenKind::Whitespace, DUMMY_SP)
     }
 
@@ -305,7 +305,7 @@ impl Token {
         mem::replace(self, Token::dummy())
     }
 
-    crate fn is_op(&self) -> bool {
+    pub fn is_op(&self) -> bool {
         match self.kind {
             OpenDelim(..) | CloseDelim(..) | Literal(..) | DocComment(..) |
             Ident(..) | Lifetime(..) | Interpolated(..) |
@@ -314,7 +314,7 @@ impl Token {
         }
     }
 
-    crate fn is_like_plus(&self) -> bool {
+    pub fn is_like_plus(&self) -> bool {
         match self.kind {
             BinOp(Plus) | BinOpEq(Plus) => true,
             _ => false,
@@ -377,7 +377,7 @@ impl Token {
     }
 
     /// Returns `true` if the token can appear at the start of a const param.
-    crate fn can_begin_const_arg(&self) -> bool {
+    pub fn can_begin_const_arg(&self) -> bool {
         match self.kind {
             OpenDelim(Brace) => true,
             Interpolated(ref nt) => match **nt {
@@ -389,7 +389,7 @@ impl Token {
     }
 
     /// Returns `true` if the token can appear at the start of a generic bound.
-    crate fn can_begin_bound(&self) -> bool {
+    pub fn can_begin_bound(&self) -> bool {
         self.is_path_start() || self.is_lifetime() || self.is_keyword(kw::For) ||
         self == &Question || self == &OpenDelim(Paren)
     }
@@ -446,13 +446,13 @@ impl Token {
     }
 
     /// Returns `true` if the token is a lifetime.
-    crate fn is_lifetime(&self) -> bool {
+    pub fn is_lifetime(&self) -> bool {
         self.lifetime().is_some()
     }
 
     /// Returns `true` if the token is a identifier whose name is the given
     /// string slice.
-    crate fn is_ident_named(&self, name: Symbol) -> bool {
+    pub fn is_ident_named(&self, name: Symbol) -> bool {
         self.ident().map_or(false, |(ident, _)| ident.name == name)
     }
 
@@ -469,7 +469,7 @@ impl Token {
     /// Would `maybe_whole_expr` in `parser.rs` return `Ok(..)`?
     /// That is, is this a pre-parsed expression dropped into the token stream
     /// (which happens while parsing the result of macro expansion)?
-    crate fn is_whole_expr(&self) -> bool {
+    pub fn is_whole_expr(&self) -> bool {
         if let Interpolated(ref nt) = self.kind {
             if let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtIdent(..) | NtBlock(_) = **nt {
                 return true;
@@ -480,16 +480,16 @@ impl Token {
     }
 
     /// Returns `true` if the token is either the `mut` or `const` keyword.
-    crate fn is_mutability(&self) -> bool {
+    pub fn is_mutability(&self) -> bool {
         self.is_keyword(kw::Mut) ||
         self.is_keyword(kw::Const)
     }
 
-    crate fn is_qpath_start(&self) -> bool {
+    pub fn is_qpath_start(&self) -> bool {
         self == &Lt || self == &BinOp(Shl)
     }
 
-    crate fn is_path_start(&self) -> bool {
+    pub fn is_path_start(&self) -> bool {
         self == &ModSep || self.is_qpath_start() || self.is_path() ||
         self.is_path_segment_keyword() || self.is_ident() && !self.is_reserved_ident()
     }
@@ -499,23 +499,23 @@ impl Token {
         self.is_non_raw_ident_where(|id| id.name == kw)
     }
 
-    crate fn is_path_segment_keyword(&self) -> bool {
+    pub fn is_path_segment_keyword(&self) -> bool {
         self.is_non_raw_ident_where(ast::Ident::is_path_segment_keyword)
     }
 
     // Returns true for reserved identifiers used internally for elided lifetimes,
     // unnamed method parameters, crate root module, error recovery etc.
-    crate fn is_special_ident(&self) -> bool {
+    pub fn is_special_ident(&self) -> bool {
         self.is_non_raw_ident_where(ast::Ident::is_special)
     }
 
     /// Returns `true` if the token is a keyword used in the language.
-    crate fn is_used_keyword(&self) -> bool {
+    pub fn is_used_keyword(&self) -> bool {
         self.is_non_raw_ident_where(ast::Ident::is_used_keyword)
     }
 
     /// Returns `true` if the token is a keyword reserved for possible future use.
-    crate fn is_unused_keyword(&self) -> bool {
+    pub fn is_unused_keyword(&self) -> bool {
         self.is_non_raw_ident_where(ast::Ident::is_unused_keyword)
     }
 
@@ -525,7 +525,7 @@ impl Token {
     }
 
     /// Returns `true` if the token is the identifier `true` or `false`.
-    crate fn is_bool_lit(&self) -> bool {
+    pub fn is_bool_lit(&self) -> bool {
         self.is_non_raw_ident_where(|id| id.name.is_bool_lit())
     }
 
@@ -537,7 +537,7 @@ impl Token {
         }
     }
 
-    crate fn glue(&self, joint: &Token) -> Option<Token> {
+    pub fn glue(&self, joint: &Token) -> Option<Token> {
         let kind = match self.kind {
             Eq => match joint.kind {
                 Eq => EqEq,
diff --git a/src/libsyntax/util/comments.rs b/src/libsyntax/util/comments.rs
index ef9226a8879..5e9b7bf8322 100644
--- a/src/libsyntax/util/comments.rs
+++ b/src/libsyntax/util/comments.rs
@@ -32,14 +32,14 @@ pub struct Comment {
     pub pos: BytePos,
 }
 
-crate fn is_line_doc_comment(s: &str) -> bool {
+pub fn is_line_doc_comment(s: &str) -> bool {
     let res = (s.starts_with("///") && *s.as_bytes().get(3).unwrap_or(&b' ') != b'/') ||
               s.starts_with("//!");
     debug!("is {:?} a doc comment? {}", s, res);
     res
 }
 
-crate fn is_block_doc_comment(s: &str) -> bool {
+pub fn is_block_doc_comment(s: &str) -> bool {
     // Prevent `/**/` from being parsed as a doc comment
     let res = ((s.starts_with("/**") && *s.as_bytes().get(3).unwrap_or(&b' ') != b'*') ||
                s.starts_with("/*!")) && s.len() >= 5;
diff --git a/src/libsyntax/util/literal.rs b/src/libsyntax/util/literal.rs
index d4c9b7850c5..af7afab6b9b 100644
--- a/src/libsyntax/util/literal.rs
+++ b/src/libsyntax/util/literal.rs
@@ -14,7 +14,7 @@ use rustc_lexer::unescape::{unescape_raw_str, unescape_raw_byte_str};
 
 use std::ascii;
 
-crate enum LitError {
+pub enum LitError {
     NotLiteral,
     LexerError,
     InvalidSuffix,
@@ -185,12 +185,12 @@ impl LitKind {
 
 impl Lit {
     /// Converts literal token into an AST literal.
-    crate fn from_lit_token(token: token::Lit, span: Span) -> Result<Lit, LitError> {
+    pub fn from_lit_token(token: token::Lit, span: Span) -> Result<Lit, LitError> {
         Ok(Lit { token, kind: LitKind::from_lit_token(token)?, span })
     }
 
     /// Converts arbitrary token into an AST literal.
-    crate fn from_token(token: &Token) -> Result<Lit, LitError> {
+    pub fn from_token(token: &Token) -> Result<Lit, LitError> {
         let lit = match token.kind {
             token::Ident(name, false) if name.is_bool_lit() =>
                 token::Lit::new(token::Bool, name, None),
@@ -217,8 +217,8 @@ impl Lit {
         Lit { token: kind.to_lit_token(), kind, span }
     }
 
-    /// Losslessly convert an AST literal into a token tree.
-    crate fn token_tree(&self) -> TokenTree {
+    /// Losslessly convert an AST literal into a token stream.
+    pub fn token_tree(&self) -> TokenTree {
         let token = match self.token.kind {
             token::Bool => token::Ident(self.token.symbol, false),
             _ => token::Literal(self.token),
diff --git a/src/libsyntax/util/parser.rs b/src/libsyntax/util/parser.rs
index edb708d7e97..df72fdc8014 100644
--- a/src/libsyntax/util/parser.rs
+++ b/src/libsyntax/util/parser.rs
@@ -69,7 +69,7 @@ pub enum Fixity {
 
 impl AssocOp {
     /// Creates a new AssocOP from a token
-    crate fn from_token(t: &Token) -> Option<AssocOp> {
+    pub fn from_token(t: &Token) -> Option<AssocOp> {
         use AssocOp::*;
         match t.kind {
             token::BinOpEq(k) => Some(AssignOp(k)),
@@ -358,7 +358,7 @@ impl ExprPrecedence {
 }
 
 /// In `let p = e`, operators with precedence `<=` this one requires parenthesis in `e`.
-crate fn prec_let_scrutinee_needs_par() -> usize {
+pub fn prec_let_scrutinee_needs_par() -> usize {
     AssocOp::LAnd.precedence()
 }
 
diff --git a/src/libsyntax_expand/Cargo.toml b/src/libsyntax_expand/Cargo.toml
index 02c711bc387..653b87f0d82 100644
--- a/src/libsyntax_expand/Cargo.toml
+++ b/src/libsyntax_expand/Cargo.toml
@@ -11,15 +11,12 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-bitflags = "1.0"
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 log = "0.4"
-scoped-tls = "1.0"
-lazy_static = "1.0.0"
 syntax_pos = { path = "../libsyntax_pos" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
+rustc_parse = { path = "../librustc_parse" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
diff --git a/src/libsyntax_expand/base.rs b/src/libsyntax_expand/base.rs
index 47835c92659..97ee241d838 100644
--- a/src/libsyntax_expand/base.rs
+++ b/src/libsyntax_expand/base.rs
@@ -1,15 +1,15 @@
 use crate::expand::{self, AstFragment, Invocation};
 
+use rustc_parse::{self, parser, DirectoryOwnership, MACRO_ARGUMENTS};
 use syntax::ast::{self, NodeId, Attribute, Name, PatKind};
 use syntax::attr::{self, HasAttrs, Stability, Deprecation};
 use syntax::source_map::SourceMap;
 use syntax::edition::Edition;
 use syntax::mut_visit::{self, MutVisitor};
-use syntax::parse::{self, parser, DirectoryOwnership};
 use syntax::ptr::P;
 use syntax::sess::ParseSess;
 use syntax::symbol::{kw, sym, Ident, Symbol};
-use syntax::{ThinVec, MACRO_ARGUMENTS};
+use syntax::ThinVec;
 use syntax::token;
 use syntax::tokenstream::{self, TokenStream};
 use syntax::visit::Visitor;
@@ -18,9 +18,9 @@ use errors::{DiagnosticBuilder, DiagnosticId};
 use smallvec::{smallvec, SmallVec};
 use syntax_pos::{FileName, Span, MultiSpan, DUMMY_SP};
 use syntax_pos::hygiene::{AstPass, ExpnId, ExpnData, ExpnKind};
-
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{self, Lrc};
+
 use std::iter;
 use std::path::PathBuf;
 use std::rc::Rc;
@@ -922,7 +922,7 @@ impl<'a> ExtCtxt<'a> {
         expand::MacroExpander::new(self, true)
     }
     pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
-        parse::stream_to_parser(self.parse_sess, stream, MACRO_ARGUMENTS)
+        rustc_parse::stream_to_parser(self.parse_sess, stream, MACRO_ARGUMENTS)
     }
     pub fn source_map(&self) -> &'a SourceMap { self.parse_sess.source_map() }
     pub fn parse_sess(&self) -> &'a ParseSess { self.parse_sess }
diff --git a/src/libsyntax_expand/config.rs b/src/libsyntax_expand/config.rs
index 9acb9948926..7b927fb55f9 100644
--- a/src/libsyntax_expand/config.rs
+++ b/src/libsyntax_expand/config.rs
@@ -1,3 +1,4 @@
+use rustc_parse::validate_attr;
 use syntax::attr::HasAttrs;
 use syntax::feature_gate::{
     feature_err,
@@ -10,11 +11,10 @@ use syntax::attr;
 use syntax::ast;
 use syntax::edition::Edition;
 use syntax::mut_visit::*;
-use syntax::parse::{self, validate_attr};
 use syntax::ptr::P;
 use syntax::sess::ParseSess;
-use syntax::symbol::sym;
 use syntax::util::map_in_place::MapInPlace;
+use syntax_pos::symbol::sym;
 
 use errors::Applicability;
 use smallvec::SmallVec;
@@ -113,7 +113,7 @@ impl<'a> StripUnconfigured<'a> {
             return vec![];
         }
 
-        let res = parse::parse_in_attr(self.sess, &attr, |p| p.parse_cfg_attr());
+        let res = rustc_parse::parse_in_attr(self.sess, &attr, |p| p.parse_cfg_attr());
         let (cfg_predicate, expanded_attrs) = match res {
             Ok(result) => result,
             Err(mut e) => {
diff --git a/src/libsyntax_expand/expand.rs b/src/libsyntax_expand/expand.rs
index 1e6c23087d8..b7f6364c2b5 100644
--- a/src/libsyntax_expand/expand.rs
+++ b/src/libsyntax_expand/expand.rs
@@ -6,15 +6,15 @@ use crate::placeholders::{placeholder, PlaceholderExpander};
 use crate::config::StripUnconfigured;
 use crate::configure;
 
+use rustc_parse::DirectoryOwnership;
+use rustc_parse::parser::Parser;
+use rustc_parse::validate_attr;
 use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
 use syntax::ast::{MacStmtStyle, StmtKind, ItemKind};
 use syntax::attr::{self, HasAttrs};
 use syntax::source_map::respan;
 use syntax::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
 use syntax::mut_visit::*;
-use syntax::parse::DirectoryOwnership;
-use syntax::parse::parser::Parser;
-use syntax::parse::validate_attr;
 use syntax::print::pprust;
 use syntax::ptr::P;
 use syntax::sess::ParseSess;
diff --git a/src/libsyntax_expand/mbe/macro_parser.rs b/src/libsyntax_expand/mbe/macro_parser.rs
index 80bf27e1a94..0dcb2c39fdc 100644
--- a/src/libsyntax_expand/mbe/macro_parser.rs
+++ b/src/libsyntax_expand/mbe/macro_parser.rs
@@ -76,9 +76,9 @@ use TokenTreeOrTokenTreeSlice::*;
 
 use crate::mbe::{self, TokenTree};
 
+use rustc_parse::Directory;
+use rustc_parse::parser::{Parser, PathStyle};
 use syntax::ast::{Ident, Name};
-use syntax::parse::Directory;
-use syntax::parse::parser::{Parser, PathStyle};
 use syntax::print::pprust;
 use syntax::sess::ParseSess;
 use syntax::symbol::{kw, sym, Symbol};
@@ -652,7 +652,7 @@ pub(super) fn parse(
         directory,
         recurse_into_modules,
         true,
-        syntax::MACRO_ARGUMENTS,
+        rustc_parse::MACRO_ARGUMENTS,
     );
 
     // A queue of possible matcher positions. We initialize it with the matcher position in which
diff --git a/src/libsyntax_expand/mbe/macro_rules.rs b/src/libsyntax_expand/mbe/macro_rules.rs
index a5fc301fbf6..72b7996628a 100644
--- a/src/libsyntax_expand/mbe/macro_rules.rs
+++ b/src/libsyntax_expand/mbe/macro_rules.rs
@@ -8,30 +8,30 @@ use crate::mbe::macro_parser::{Error, Failure, Success};
 use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedParseResult};
 use crate::mbe::transcribe::transcribe;
 
+use rustc_parse::parser::Parser;
+use rustc_parse::Directory;
 use syntax::ast;
 use syntax::attr::{self, TransparencyError};
 use syntax::edition::Edition;
 use syntax::feature_gate::Features;
-use syntax::parse::parser::Parser;
-use syntax::parse::Directory;
 use syntax::print::pprust;
 use syntax::sess::ParseSess;
 use syntax::symbol::{kw, sym, Symbol};
 use syntax::token::{self, NtTT, Token, TokenKind::*};
 use syntax::tokenstream::{DelimSpan, TokenStream};
+use syntax_pos::hygiene::Transparency;
+use syntax_pos::Span;
 
 use errors::{DiagnosticBuilder, FatalError};
 use log::debug;
-use syntax_pos::hygiene::Transparency;
-use syntax_pos::Span;
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::sync::Lrc;
 use std::borrow::Cow;
 use std::collections::hash_map::Entry;
 use std::{mem, slice};
 
 use errors::Applicability;
-use rustc_data_structures::sync::Lrc;
 
 const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
                                         `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, \
diff --git a/src/libsyntax_expand/parse/lexer/tests.rs b/src/libsyntax_expand/parse/lexer/tests.rs
index 3d5726fa601..d8a1c359c95 100644
--- a/src/libsyntax_expand/parse/lexer/tests.rs
+++ b/src/libsyntax_expand/parse/lexer/tests.rs
@@ -1,18 +1,18 @@
 use crate::config::process_configure_mod;
 
 use rustc_data_structures::sync::Lrc;
+use rustc_parse::lexer::StringReader;
 use syntax::token::{self, Token, TokenKind};
 use syntax::sess::ParseSess;
 use syntax::source_map::{SourceMap, FilePathMapping};
 use syntax::util::comments::is_doc_comment;
 use syntax::with_default_globals;
-use syntax::parse::lexer::StringReader;
 use syntax_pos::symbol::Symbol;
+use syntax_pos::{BytePos, Span};
 
 use errors::{Handler, emitter::EmitterWriter};
 use std::io;
 use std::path::PathBuf;
-use syntax_pos::{BytePos, Span};
 
 fn mk_sess(sm: Lrc<SourceMap>) -> ParseSess {
     let emitter = EmitterWriter::new(
diff --git a/src/libsyntax_expand/parse/tests.rs b/src/libsyntax_expand/parse/tests.rs
index 01739809f7f..60911617995 100644
--- a/src/libsyntax_expand/parse/tests.rs
+++ b/src/libsyntax_expand/parse/tests.rs
@@ -1,6 +1,7 @@
 use crate::config::process_configure_mod;
 use crate::tests::{matches_codepattern, string_to_stream, with_error_checking_parse};
 
+use rustc_parse::new_parser_from_source_str;
 use syntax::ast::{self, Name, PatKind};
 use syntax::attr::first_attr_value_str_by_name;
 use syntax::sess::ParseSess;
@@ -12,7 +13,6 @@ use syntax::symbol::{kw, sym};
 use syntax::tokenstream::{DelimSpan, TokenTree, TokenStream};
 use syntax::visit;
 use syntax::with_default_globals;
-use syntax::parse::new_parser_from_source_str;
 use syntax_pos::{Span, BytePos, Pos, FileName};
 use errors::PResult;
 
diff --git a/src/libsyntax_expand/proc_macro.rs b/src/libsyntax_expand/proc_macro.rs
index 51c368bbaa6..db981fae5c2 100644
--- a/src/libsyntax_expand/proc_macro.rs
+++ b/src/libsyntax_expand/proc_macro.rs
@@ -4,7 +4,6 @@ use crate::proc_macro_server;
 use syntax::ast::{self, ItemKind, Attribute, Mac};
 use syntax::attr::{mark_used, mark_known};
 use syntax::errors::{Applicability, FatalError};
-use syntax::parse;
 use syntax::symbol::sym;
 use syntax::token;
 use syntax::tokenstream::{self, TokenStream};
@@ -135,7 +134,11 @@ impl MultiItemModifier for ProcMacroDerive {
         let error_count_before = ecx.parse_sess.span_diagnostic.err_count();
         let msg = "proc-macro derive produced unparseable tokens";
 
-        let mut parser = parse::stream_to_parser(ecx.parse_sess, stream, Some("proc-macro derive"));
+        let mut parser = rustc_parse::stream_to_parser(
+            ecx.parse_sess,
+            stream,
+            Some("proc-macro derive"),
+        );
         let mut items = vec![];
 
         loop {
@@ -200,7 +203,7 @@ crate fn collect_derives(cx: &mut ExtCtxt<'_>, attrs: &mut Vec<ast::Attribute>)
             if attr.get_normal_item().tokens.is_empty() {
                 return Ok(Vec::new());
             }
-            parse::parse_in_attr(cx.parse_sess, attr, |p| p.parse_derive_paths())
+            rustc_parse::parse_in_attr(cx.parse_sess, attr, |p| p.parse_derive_paths())
         };
 
         match parse_derive_paths(attr) {
diff --git a/src/libsyntax_expand/proc_macro_server.rs b/src/libsyntax_expand/proc_macro_server.rs
index e96b6092787..43a9d4169f6 100644
--- a/src/libsyntax_expand/proc_macro_server.rs
+++ b/src/libsyntax_expand/proc_macro_server.rs
@@ -1,17 +1,17 @@
 use crate::base::ExtCtxt;
 
+use rustc_parse::{parse_stream_from_source_str, nt_to_tokenstream};
 use syntax::ast;
-use syntax::parse;
 use syntax::util::comments;
 use syntax::print::pprust;
 use syntax::sess::ParseSess;
 use syntax::token;
 use syntax::tokenstream::{self, DelimSpan, IsJoint::*, TokenStream, TreeAndJoint};
+use syntax_pos::{BytePos, FileName, MultiSpan, Pos, SourceFile, Span};
+use syntax_pos::symbol::{kw, sym, Symbol};
 
 use errors::Diagnostic;
 use rustc_data_structures::sync::Lrc;
-use syntax_pos::{BytePos, FileName, MultiSpan, Pos, SourceFile, Span};
-use syntax_pos::symbol::{kw, sym, Symbol};
 
 use pm::{Delimiter, Level, LineColumn, Spacing};
 use pm::bridge::{server, TokenTree};
@@ -178,7 +178,7 @@ impl FromInternal<(TreeAndJoint, &'_ ParseSess, &'_ mut Vec<Self>)>
             }
 
             Interpolated(nt) => {
-                let stream = parse::nt_to_tokenstream(&nt, sess, span);
+                let stream = nt_to_tokenstream(&nt, sess, span);
                 TokenTree::Group(Group {
                     delimiter: Delimiter::None,
                     stream,
@@ -402,7 +402,7 @@ impl server::TokenStream for Rustc<'_> {
         stream.is_empty()
     }
     fn from_str(&mut self, src: &str) -> Self::TokenStream {
-        parse::parse_stream_from_source_str(
+        parse_stream_from_source_str(
             FileName::proc_macro_source_code(src),
             src.to_string(),
             self.sess,
diff --git a/src/libsyntax_expand/tests.rs b/src/libsyntax_expand/tests.rs
index 461d9a43954..2683620e845 100644
--- a/src/libsyntax_expand/tests.rs
+++ b/src/libsyntax_expand/tests.rs
@@ -1,10 +1,10 @@
 use crate::config::process_configure_mod;
+use rustc_parse::{source_file_to_stream, new_parser_from_source_str, parser::Parser};
 use syntax::ast;
 use syntax::tokenstream::TokenStream;
 use syntax::sess::ParseSess;
 use syntax::source_map::{SourceMap, FilePathMapping};
 use syntax::with_default_globals;
-use syntax::parse::{source_file_to_stream, new_parser_from_source_str, parser::Parser};
 use syntax_pos::{BytePos, Span, MultiSpan};
 
 use errors::emitter::EmitterWriter;
diff --git a/src/libsyntax_ext/Cargo.toml b/src/libsyntax_ext/Cargo.toml
index 703d51e1c4c..5ae8b3a3e0c 100644
--- a/src/libsyntax_ext/Cargo.toml
+++ b/src/libsyntax_ext/Cargo.toml
@@ -14,6 +14,7 @@ errors = { path = "../librustc_errors", package = "rustc_errors" }
 fmt_macros = { path = "../libfmt_macros" }
 log = "0.4"
 rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_parse = { path = "../librustc_parse" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
diff --git a/src/libsyntax_ext/assert.rs b/src/libsyntax_ext/assert.rs
index a15423b7ad8..c4f3c03813f 100644
--- a/src/libsyntax_ext/assert.rs
+++ b/src/libsyntax_ext/assert.rs
@@ -1,13 +1,13 @@
 use errors::{Applicability, DiagnosticBuilder};
 
+use rustc_parse::parser::Parser;
 use syntax::ast::{self, *};
-use syntax_expand::base::*;
 use syntax::token::{self, TokenKind};
-use syntax::parse::parser::Parser;
 use syntax::print::pprust;
 use syntax::ptr::P;
 use syntax::symbol::{sym, Symbol};
 use syntax::tokenstream::{TokenStream, TokenTree};
+use syntax_expand::base::*;
 use syntax_pos::{Span, DUMMY_SP};
 
 pub fn expand_assert<'cx>(
diff --git a/src/libsyntax_ext/cmdline_attrs.rs b/src/libsyntax_ext/cmdline_attrs.rs
index 171f2405573..5c3009c432c 100644
--- a/src/libsyntax_ext/cmdline_attrs.rs
+++ b/src/libsyntax_ext/cmdline_attrs.rs
@@ -2,7 +2,6 @@
 
 use syntax::ast::{self, AttrItem, AttrStyle};
 use syntax::attr::mk_attr;
-use syntax::parse;
 use syntax::token;
 use syntax::sess::ParseSess;
 use syntax_expand::panictry;
@@ -10,7 +9,7 @@ use syntax_pos::FileName;
 
 pub fn inject(mut krate: ast::Crate, parse_sess: &ParseSess, attrs: &[String]) -> ast::Crate {
     for raw_attr in attrs {
-        let mut parser = parse::new_parser_from_source_str(
+        let mut parser = rustc_parse::new_parser_from_source_str(
             parse_sess,
             FileName::cli_crate_attr_source_code(&raw_attr),
             raw_attr.clone(),
diff --git a/src/libsyntax_ext/source_util.rs b/src/libsyntax_ext/source_util.rs
index 7e47b40714d..120b533a69b 100644
--- a/src/libsyntax_ext/source_util.rs
+++ b/src/libsyntax_ext/source_util.rs
@@ -1,13 +1,13 @@
-use syntax_expand::panictry;
-use syntax_expand::base::{self, *};
+use rustc_parse::{self, DirectoryOwnership, new_sub_parser_from_file, parser::Parser};
 use syntax::ast;
-use syntax::parse::{self, DirectoryOwnership};
 use syntax::print::pprust;
 use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax::token;
 use syntax::tokenstream::TokenStream;
 use syntax::early_buffered_lints::BufferedEarlyLintId;
+use syntax_expand::panictry;
+use syntax_expand::base::{self, *};
 
 use smallvec::SmallVec;
 use syntax_pos::{self, Pos, Span};
@@ -85,10 +85,10 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
         },
     };
     let directory_ownership = DirectoryOwnership::Owned { relative: None };
-    let p = parse::new_sub_parser_from_file(cx.parse_sess(), &file, directory_ownership, None, sp);
+    let p = new_sub_parser_from_file(cx.parse_sess(), &file, directory_ownership, None, sp);
 
     struct ExpandResult<'a> {
-        p: parse::parser::Parser<'a>,
+        p: Parser<'a>,
     }
     impl<'a> base::MacResult for ExpandResult<'a> {
         fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
diff --git a/src/libsyntax_ext/util.rs b/src/libsyntax_ext/util.rs
index c8f0eb4ad25..e59daab1770 100644
--- a/src/libsyntax_ext/util.rs
+++ b/src/libsyntax_ext/util.rs
@@ -1,7 +1,7 @@
+use rustc_parse::validate_attr;
 use syntax_pos::Symbol;
 use syntax::ast::MetaItem;
 use syntax::attr::AttributeTemplate;
-use syntax::parse::validate_attr;
 use syntax_expand::base::ExtCtxt;
 
 pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) {
diff --git a/src/test/ui-fulldeps/ast_stmt_expr_attr.rs b/src/test/ui-fulldeps/ast_stmt_expr_attr.rs
index 3d2181d4e37..0bf17302b06 100644
--- a/src/test/ui-fulldeps/ast_stmt_expr_attr.rs
+++ b/src/test/ui-fulldeps/ast_stmt_expr_attr.rs
@@ -7,9 +7,13 @@
 
 extern crate syntax;
 extern crate syntax_expand;
+extern crate rustc_parse;
 extern crate rustc_errors;
 
 use rustc_errors::PResult;
+use rustc_parse::parser::attr::*;
+use rustc_parse::new_parser_from_source_str;
+use rustc_parse::parser::Parser;
 use syntax::ast::*;
 use syntax::attr::*;
 use syntax::ast;
@@ -17,9 +21,6 @@ use syntax::sess::ParseSess;
 use syntax::source_map::{FilePathMapping, FileName};
 use syntax::ptr::P;
 use syntax::print::pprust;
-use syntax::parse::parser::attr::*;
-use syntax::parse::new_parser_from_source_str;
-use syntax::parse::parser::Parser;
 use syntax::token;
 use syntax_expand::config::process_configure_mod;
 use std::fmt;
diff --git a/src/test/ui-fulldeps/mod_dir_path_canonicalized.rs b/src/test/ui-fulldeps/mod_dir_path_canonicalized.rs
index 472440e2e14..2411b9634c3 100644
--- a/src/test/ui-fulldeps/mod_dir_path_canonicalized.rs
+++ b/src/test/ui-fulldeps/mod_dir_path_canonicalized.rs
@@ -6,11 +6,12 @@
 
 extern crate syntax;
 extern crate syntax_expand;
+extern crate rustc_parse;
 
+use rustc_parse::new_parser_from_file;
 use std::path::Path;
 use syntax::sess::ParseSess;
 use syntax::source_map::FilePathMapping;
-use syntax::parse::new_parser_from_file;
 use syntax_expand::config::process_configure_mod;
 
 #[path = "mod_dir_simple/test.rs"]
diff --git a/src/test/ui-fulldeps/pprust-expr-roundtrip.rs b/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
index 99da605f357..5da0297f645 100644
--- a/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
+++ b/src/test/ui-fulldeps/pprust-expr-roundtrip.rs
@@ -22,14 +22,15 @@
 extern crate rustc_data_structures;
 extern crate syntax;
 extern crate syntax_expand;
+extern crate rustc_parse;
 
 use rustc_data_structures::thin_vec::ThinVec;
+use rustc_parse::new_parser_from_source_str;
 use syntax::ast::*;
 use syntax::sess::ParseSess;
 use syntax::source_map::{Spanned, DUMMY_SP, FileName};
 use syntax::source_map::FilePathMapping;
 use syntax::mut_visit::{self, MutVisitor, visit_clobber};
-use syntax::parse::new_parser_from_source_str;
 use syntax::print::pprust;
 use syntax::ptr::P;
 use syntax_expand::config::process_configure_mod;