Auto merge of #66189 - Centril:rollup-3bsf45s, r=Centril

Rollup of 5 pull requests

Successful merges:

 - #63793 (Have tidy ensure that we document all `unsafe` blocks in libcore)
 - #64696 ([rustdoc] add sub settings)
 - #65916 (syntax: move stuff around)
 - #66087 (Update some build-pass ui tests to use check-pass where applicable)
 - #66182 (invalid_value lint: fix help text)

Failed merges:

r? @ghost

33 files changed, 109 insertions, 104 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 67d1acbccfb..18151a1586c 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -24,9 +24,9 @@ pub use crate::util::parser::ExprPrecedence;
 
 pub use syntax_pos::symbol::{Ident, Symbol as Name};
 
-use crate::parse::token::{self, DelimToken};
 use crate::ptr::P;
 use crate::source_map::{dummy_spanned, respan, Spanned};
+use crate::token::{self, DelimToken};
 use crate::tokenstream::TokenStream;
 
 use syntax_pos::symbol::{kw, sym, Symbol};
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index c663995eb8f..c639431794c 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -14,10 +14,8 @@ use crate::ast::{MetaItem, MetaItemKind, NestedMetaItem};
 use crate::ast::{Lit, LitKind, Expr, Item, Local, Stmt, StmtKind, GenericParam};
 use crate::mut_visit::visit_clobber;
 use crate::source_map::{BytePos, Spanned};
-use crate::parse::lexer::comments::doc_comment_style;
 use crate::parse;
-use crate::parse::PResult;
-use crate::parse::token::{self, Token};
+use crate::token::{self, Token};
 use crate::ptr::P;
 use crate::sess::ParseSess;
 use crate::symbol::{sym, Symbol};
@@ -25,6 +23,8 @@ use crate::ThinVec;
 use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
 use crate::GLOBALS;
 
+use errors::PResult;
+
 use log::debug;
 use syntax_pos::Span;
 
@@ -400,11 +400,11 @@ pub fn mk_attr_outer(item: MetaItem) -> Attribute {
     mk_attr(AttrStyle::Outer, item.path, item.kind.tokens(item.span), item.span)
 }
 
-pub fn mk_doc_comment(comment: Symbol, span: Span) -> Attribute {
+pub fn mk_doc_comment(style: AttrStyle, comment: Symbol, span: Span) -> Attribute {
     Attribute {
         kind: AttrKind::DocComment(comment),
         id: mk_attr_id(),
-        style: doc_comment_style(&comment.as_str()),
+        style,
         span,
     }
 }
diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs
index 5b1493ebc9b..ecff89ad59b 100644
--- a/src/libsyntax/feature_gate/check.rs
+++ b/src/libsyntax/feature_gate/check.rs
@@ -11,7 +11,7 @@ use crate::attr::{self, check_builtin_attribute};
 use crate::source_map::Spanned;
 use crate::edition::{ALL_EDITIONS, Edition};
 use crate::visit::{self, FnKind, Visitor};
-use crate::parse::token;
+use crate::token;
 use crate::sess::ParseSess;
 use crate::symbol::{Symbol, sym};
 use crate::tokenstream::TokenTree;
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 7be6e6c7e18..1b17de529c4 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -85,7 +85,10 @@ pub mod diagnostics {
 pub mod error_codes;
 
 pub mod util {
+    crate mod classify;
+    pub mod comments;
     pub mod lev_distance;
+    crate mod literal;
     pub mod node_count;
     pub mod parser;
     pub mod map_in_place;
@@ -107,6 +110,7 @@ pub mod show_span;
 pub use syntax_pos::edition;
 pub use syntax_pos::symbol;
 pub mod sess;
+pub mod token;
 pub mod tokenstream;
 pub mod visit;
 
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index 7261601e144..0c90652526d 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -9,7 +9,7 @@
 
 use crate::ast::*;
 use crate::source_map::{Spanned, respan};
-use crate::parse::token::{self, Token};
+use crate::token::{self, Token};
 use crate::ptr::P;
 use crate::ThinVec;
 use crate::tokenstream::*;
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index e2a7ea28b9b..b1b7b08c78a 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -1,7 +1,7 @@
-use crate::parse::token::{self, Token, TokenKind};
+use crate::token::{self, Token, TokenKind};
 use crate::sess::ParseSess;
 use crate::symbol::{sym, Symbol};
-use crate::parse::unescape_error_reporting::{emit_unescape_error, push_escaped_char};
+use crate::util::comments;
 
 use errors::{FatalError, DiagnosticBuilder};
 use syntax_pos::{BytePos, Pos, Span};
@@ -16,9 +16,10 @@ use log::debug;
 #[cfg(test)]
 mod tests;
 
-pub mod comments;
 mod tokentrees;
 mod unicode_chars;
+mod unescape_error_reporting;
+use unescape_error_reporting::{emit_unescape_error, push_escaped_char};
 
 #[derive(Clone, Debug)]
 pub struct UnmatchedBrace {
@@ -178,7 +179,7 @@ impl<'a> StringReader<'a> {
             rustc_lexer::TokenKind::LineComment => {
                 let string = self.str_from(start);
                 // comments with only more "/"s are not doc comments
-                let tok = if is_doc_comment(string) {
+                let tok = if comments::is_line_doc_comment(string) {
                     self.forbid_bare_cr(start, string, "bare CR not allowed in doc-comment");
                     token::DocComment(Symbol::intern(string))
                 } else {
@@ -191,7 +192,7 @@ impl<'a> StringReader<'a> {
                 let string = self.str_from(start);
                 // block comments starting with "/**" or "/*!" are doc-comments
                 // but comments with only "*"s between two "/"s are not
-                let is_doc_comment = is_block_doc_comment(string);
+                let is_doc_comment = comments::is_block_doc_comment(string);
 
                 if !terminated {
                     let msg = if is_doc_comment {
@@ -642,18 +643,3 @@ impl<'a> StringReader<'a> {
         }
     }
 }
-
-fn is_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
-}
-
-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;
-    debug!("is {:?} a doc comment? {}", s, res);
-    res
-}
diff --git a/src/libsyntax/parse/lexer/tests.rs b/src/libsyntax/parse/lexer/tests.rs
index de301b1fc49..baa6fb59537 100644
--- a/src/libsyntax/parse/lexer/tests.rs
+++ b/src/libsyntax/parse/lexer/tests.rs
@@ -2,7 +2,8 @@ use super::*;
 
 use crate::symbol::Symbol;
 use crate::source_map::{SourceMap, FilePathMapping};
-use crate::parse::token;
+use crate::token;
+use crate::util::comments::is_doc_comment;
 use crate::with_default_globals;
 
 use errors::{Handler, emitter::EmitterWriter};
diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs
index de8ac2c71e8..2b056434d4d 100644
--- a/src/libsyntax/parse/lexer/tokentrees.rs
+++ b/src/libsyntax/parse/lexer/tokentrees.rs
@@ -4,10 +4,11 @@ use syntax_pos::Span;
 use super::{StringReader, UnmatchedBrace};
 
 use crate::print::pprust::token_to_string;
-use crate::parse::token::{self, Token};
-use crate::parse::PResult;
+use crate::token::{self, Token};
 use crate::tokenstream::{DelimSpan, IsJoint::{self, *}, TokenStream, TokenTree, TreeAndJoint};
 
+use errors::PResult;
+
 impl<'a> StringReader<'a> {
     crate fn into_token_trees(self) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
         let mut tt_reader = TokenTreesReader {
diff --git a/src/libsyntax/parse/unescape_error_reporting.rs b/src/libsyntax/parse/lexer/unescape_error_reporting.rs
index 5565015179c..5565015179c 100644
--- a/src/libsyntax/parse/unescape_error_reporting.rs
+++ b/src/libsyntax/parse/lexer/unescape_error_reporting.rs
diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/libsyntax/parse/lexer/unicode_chars.rs
index 525b4215aff..6eb995b61d3 100644
--- a/src/libsyntax/parse/lexer/unicode_chars.rs
+++ b/src/libsyntax/parse/lexer/unicode_chars.rs
@@ -4,7 +4,7 @@
 use super::StringReader;
 use errors::{Applicability, DiagnosticBuilder};
 use syntax_pos::{BytePos, Pos, Span, symbol::kw};
-use crate::parse::token;
+use crate::token;
 
 #[rustfmt::skip] // for line breaks
 const UNICODE_ARRAY: &[(char, &str, char)] = &[
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index b688dce87c1..18550762017 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -2,14 +2,12 @@
 
 use crate::ast;
 use crate::parse::parser::{Parser, emit_unclosed_delims, make_unclosed_delims_error};
-use crate::parse::token::Nonterminal;
+use crate::token::{self, Nonterminal};
 use crate::tokenstream::{self, TokenStream, TokenTree};
 use crate::print::pprust;
 use crate::sess::ParseSess;
 
-use errors::{FatalError, Level, Diagnostic, DiagnosticBuilder};
-#[cfg(target_arch = "x86_64")]
-use rustc_data_structures::static_assert_size;
+use errors::{PResult, FatalError, Level, Diagnostic};
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::{Span, SourceFile, FileName};
 
@@ -25,18 +23,6 @@ mod tests;
 #[macro_use]
 pub mod parser;
 pub mod lexer;
-pub mod token;
-
-crate mod classify;
-crate mod literal;
-crate mod unescape_error_reporting;
-
-pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
-
-// `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
-// (See also the comment on `DiagnosticBuilderInner`.)
-#[cfg(target_arch = "x86_64")]
-static_assert_size!(PResult<'_, bool>, 16);
 
 #[derive(Clone)]
 pub struct Directory<'a> {
diff --git a/src/libsyntax/parse/parser/attr.rs b/src/libsyntax/parse/parser/attr.rs
index 1c292661f24..31f0a02a483 100644
--- a/src/libsyntax/parse/parser/attr.rs
+++ b/src/libsyntax/parse/parser/attr.rs
@@ -1,10 +1,14 @@
-use super::{SeqSep, PResult, Parser, TokenType, PathStyle};
+use super::{SeqSep, Parser, TokenType, PathStyle};
 use crate::attr;
 use crate::ast;
-use crate::parse::token::{self, Nonterminal, DelimToken};
+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 errors::PResult;
+
 use log::debug;
 
 #[derive(Debug)]
@@ -43,7 +47,7 @@ impl<'a> Parser<'a> {
                     just_parsed_doc_comment = false;
                 }
                 token::DocComment(s) => {
-                    let attr = attr::mk_doc_comment(s, self.token.span);
+                    let attr = self.mk_doc_comment(s);
                     if attr.style != ast::AttrStyle::Outer {
                         let mut err = self.fatal("expected outer doc comment");
                         err.note("inner doc comments like this (starting with \
@@ -60,6 +64,11 @@ impl<'a> Parser<'a> {
         Ok(attrs)
     }
 
+    fn mk_doc_comment(&self, s: Symbol) -> ast::Attribute {
+        let style = comments::doc_comment_style(&s.as_str());
+        attr::mk_doc_comment(style, s, self.token.span)
+    }
+
     /// Matches `attribute = # ! [ meta_item ]`.
     ///
     /// If `permit_inner` is `true`, then a leading `!` indicates an inner
@@ -228,7 +237,7 @@ impl<'a> Parser<'a> {
                 }
                 token::DocComment(s) => {
                     // We need to get the position of this token before we bump.
-                    let attr = attr::mk_doc_comment(s, self.token.span);
+                    let attr = self.mk_doc_comment(s);
                     if attr.style == ast::AttrStyle::Inner {
                         attrs.push(attr);
                         self.bump();
diff --git a/src/libsyntax/parse/parser/diagnostics.rs b/src/libsyntax/parse/parser/diagnostics.rs
index 49a517a5c44..26d7f48025e 100644
--- a/src/libsyntax/parse/parser/diagnostics.rs
+++ b/src/libsyntax/parse/parser/diagnostics.rs
@@ -1,18 +1,16 @@
-use super::{
-    BlockMode, PathStyle, SemiColonMode, TokenType, TokenExpectType,
-    SeqSep, PResult, Parser
-};
+use super::{BlockMode, PathStyle, SemiColonMode, TokenType, TokenExpectType, SeqSep, Parser};
 use crate::ast::{
     self, Param, BinOpKind, BindingMode, BlockCheckMode, Expr, ExprKind, Ident, Item, ItemKind,
     Mutability, Pat, PatKind, PathSegment, QSelf, Ty, TyKind,
 };
-use crate::parse::token::{self, TokenKind, token_can_begin_expr};
+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 errors::{Applicability, DiagnosticBuilder, DiagnosticId, pluralize};
+
+use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, pluralize};
 use rustc_data_structures::fx::FxHashSet;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan, SpanSnippetError};
 use log::{debug, trace};
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 509e6482dcc..800074035ce 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -1,24 +1,23 @@
-use super::{Parser, PResult, Restrictions, PrevTokenKind, TokenType, PathStyle, BlockMode};
+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::parse::literal::LitError;
-
 use crate::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::parse::classify;
-use crate::parse::token::{self, Token, TokenKind};
+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::Applicability;
+use errors::{PResult, Applicability};
 use syntax_pos::symbol::{kw, sym};
 use syntax_pos::Symbol;
 use std::mem;
diff --git a/src/libsyntax/parse/parser/generics.rs b/src/libsyntax/parse/parser/generics.rs
index 3c094750b4d..ae9ecd8fe39 100644
--- a/src/libsyntax/parse/parser/generics.rs
+++ b/src/libsyntax/parse/parser/generics.rs
@@ -1,11 +1,13 @@
-use super::{Parser, PResult};
+use super::Parser;
 
 use crate::ast::{self, WhereClause, GenericParam, GenericParamKind, GenericBounds, Attribute};
-use crate::parse::token;
+use crate::token;
 use crate::source_map::DUMMY_SP;
 
 use syntax_pos::symbol::{kw, sym};
 
+use errors::PResult;
+
 impl<'a> Parser<'a> {
     /// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
     ///
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index 9d543055f23..3c618d75d34 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -1,4 +1,4 @@
-use super::{Parser, PResult, PathStyle};
+use super::{Parser, PathStyle};
 use super::diagnostics::{Error, dummy_arg, ConsumeClosingDelim};
 
 use crate::maybe_whole;
@@ -17,7 +17,7 @@ use crate::ThinVec;
 
 use log::debug;
 use std::mem;
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId, StashKey};
+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.
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser/mod.rs
index 1284e89f195..455f4172f5f 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser/mod.rs
@@ -15,10 +15,10 @@ use crate::ast::{
     self, Abi, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
     IsAsync, MacDelimiter, Mutability, StrStyle, Visibility, VisibilityKind, Unsafety,
 };
-use crate::parse::{PResult, Directory, DirectoryOwnership};
+use crate::parse::{Directory, DirectoryOwnership};
 use crate::parse::lexer::UnmatchedBrace;
-use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
-use crate::parse::token::{self, Token, TokenKind, DelimToken};
+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;
@@ -27,7 +27,7 @@ use crate::symbol::{kw, sym, Symbol};
 use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::ThinVec;
 
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
+use errors::{PResult, Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
 use log::debug;
 
diff --git a/src/libsyntax/parse/parser/module.rs b/src/libsyntax/parse/parser/module.rs
index 242a17659a0..72049daaed3 100644
--- a/src/libsyntax/parse/parser/module.rs
+++ b/src/libsyntax/parse/parser/module.rs
@@ -1,14 +1,16 @@
-use super::{Parser, PResult};
+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::parse::token::{self, TokenKind};
+use crate::token::{self, TokenKind};
 use crate::source_map::{SourceMap, Span, DUMMY_SP, FileName};
 use crate::symbol::sym;
 
+use errors::PResult;
+
 use std::path::{self, Path, PathBuf};
 
 /// Information about the path to a module.
diff --git a/src/libsyntax/parse/parser/pat.rs b/src/libsyntax/parse/parser/pat.rs
index cc8738edff7..f347300da71 100644
--- a/src/libsyntax/parse/parser/pat.rs
+++ b/src/libsyntax/parse/parser/pat.rs
@@ -1,16 +1,16 @@
-use super::{Parser, PResult, PathStyle};
+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::parse::token::{self};
+use crate::token;
 use crate::print::pprust;
 use crate::source_map::{respan, Span, Spanned};
 use crate::ThinVec;
 use syntax_pos::symbol::{kw, sym};
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{PResult, Applicability, DiagnosticBuilder};
 
 type Expected = Option<&'static str>;
 
diff --git a/src/libsyntax/parse/parser/path.rs b/src/libsyntax/parse/parser/path.rs
index 4438d61d9ee..9ceb3ba1eb4 100644
--- a/src/libsyntax/parse/parser/path.rs
+++ b/src/libsyntax/parse/parser/path.rs
@@ -1,15 +1,15 @@
-use super::{Parser, PResult, TokenType};
+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::parse::token::{self, Token};
+use crate::token::{self, Token};
 use crate::source_map::{Span, BytePos};
 use syntax_pos::symbol::{kw, sym};
 
 use std::mem;
 use log::debug;
-use errors::{Applicability, pluralize};
+use errors::{PResult, Applicability, pluralize};
 
 /// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
diff --git a/src/libsyntax/parse/parser/stmt.rs b/src/libsyntax/parse/parser/stmt.rs
index 12c530f3cbb..30e47b7a0b2 100644
--- a/src/libsyntax/parse/parser/stmt.rs
+++ b/src/libsyntax/parse/parser/stmt.rs
@@ -1,4 +1,4 @@
-use super::{Parser, PResult, Restrictions, PrevTokenKind, SemiColonMode, BlockMode};
+use super::{Parser, Restrictions, PrevTokenKind, SemiColonMode, BlockMode};
 use super::expr::LhsExpr;
 use super::path::PathStyle;
 use super::pat::GateOr;
@@ -8,13 +8,14 @@ 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::{classify, DirectoryOwnership};
-use crate::parse::token;
+use crate::parse::DirectoryOwnership;
+use crate::util::classify;
+use crate::token;
 use crate::source_map::{respan, Span};
 use crate::symbol::{kw, sym};
 
 use std::mem;
-use errors::Applicability;
+use errors::{PResult, Applicability};
 
 impl<'a> Parser<'a> {
     /// Parses a statement. This stops just before trailing semicolons on everything but items.
diff --git a/src/libsyntax/parse/parser/ty.rs b/src/libsyntax/parse/parser/ty.rs
index b770b90705c..a891634e611 100644
--- a/src/libsyntax/parse/parser/ty.rs
+++ b/src/libsyntax/parse/parser/ty.rs
@@ -1,4 +1,4 @@
-use super::{Parser, PResult, PathStyle, PrevTokenKind, TokenType};
+use super::{Parser, PathStyle, PrevTokenKind, TokenType};
 use super::item::ParamCfg;
 
 use crate::{maybe_whole, maybe_recover_from_interpolated_ty_qpath};
@@ -6,11 +6,11 @@ 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::parse::token::{self, Token};
+use crate::token::{self, Token};
 use crate::source_map::Span;
 use crate::symbol::{kw};
 
-use errors::{Applicability, pluralize};
+use errors::{PResult, Applicability, pluralize};
 
 /// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
 /// `IDENT<<u8 as Trait>::AssocTy>`.
diff --git a/src/libsyntax/parse/tests.rs b/src/libsyntax/parse/tests.rs
index 169eb954efa..27ca2b6472f 100644
--- a/src/libsyntax/parse/tests.rs
+++ b/src/libsyntax/parse/tests.rs
@@ -2,9 +2,9 @@ use super::*;
 
 use crate::ast::{self, Name, PatKind};
 use crate::attr::first_attr_value_str_by_name;
-use crate::parse::{ParseSess, PResult};
-use crate::parse::new_parser_from_source_str;
-use crate::parse::token::Token;
+use crate::sess::ParseSess;
+use crate::parse::{PResult, new_parser_from_source_str};
+use crate::token::Token;
 use crate::print::pprust::item_to_string;
 use crate::ptr::P;
 use crate::source_map::FilePathMapping;
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 1d59c13a9d0..4ca4bdeb046 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -2,14 +2,14 @@ use crate::ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
 use crate::ast::{SelfKind, GenericBound, TraitBoundModifier};
 use crate::ast::{Attribute, MacDelimiter, GenericArg};
 use crate::util::parser::{self, AssocOp, Fixity};
+use crate::util::comments;
 use crate::attr;
 use crate::source_map::{self, SourceMap, Spanned};
-use crate::parse::token::{self, BinOpToken, DelimToken, Nonterminal, Token, TokenKind};
-use crate::parse::lexer::comments;
-use crate::parse;
+use crate::token::{self, BinOpToken, DelimToken, Nonterminal, Token, TokenKind};
 use crate::print::pp::{self, Breaks};
 use crate::print::pp::Breaks::{Consistent, Inconsistent};
 use crate::ptr::P;
+use crate::util::classify;
 use crate::sess::ParseSess;
 use crate::symbol::{kw, sym};
 use crate::tokenstream::{self, TokenStream, TokenTree};
@@ -1659,7 +1659,7 @@ impl<'a> State<'a> {
             ast::StmtKind::Expr(ref expr) => {
                 self.space_if_not_bol();
                 self.print_expr_outer_attr_style(expr, false);
-                if parse::classify::expr_requires_semi_to_be_stmt(expr) {
+                if classify::expr_requires_semi_to_be_stmt(expr) {
                     self.s.word(";");
                 }
             }
diff --git a/src/libsyntax/tests.rs b/src/libsyntax/tests.rs
index e73c8b43bcc..ed457c3627f 100644
--- a/src/libsyntax/tests.rs
+++ b/src/libsyntax/tests.rs
@@ -1,5 +1,5 @@
 use crate::ast;
-use crate::parse::{PResult, source_file_to_stream};
+use crate::parse::source_file_to_stream;
 use crate::parse::new_parser_from_source_str;
 use crate::parse::parser::Parser;
 use crate::sess::ParseSess;
@@ -8,7 +8,7 @@ use crate::tokenstream::TokenStream;
 use crate::with_default_globals;
 
 use errors::emitter::EmitterWriter;
-use errors::Handler;
+use errors::{PResult, Handler};
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::{BytePos, Span, MultiSpan};
 
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/token.rs
index 6f3da344ccf..6f3da344ccf 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/token.rs
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index a51d208704a..6e1bb85ce1a 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -13,7 +13,7 @@
 //! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
 //! ownership of the original.
 
-use crate::parse::token::{self, DelimToken, Token, TokenKind};
+use crate::token::{self, DelimToken, Token, TokenKind};
 
 use syntax_pos::{Span, DUMMY_SP};
 #[cfg(target_arch = "x86_64")]
diff --git a/src/libsyntax/parse/classify.rs b/src/libsyntax/util/classify.rs
index 44560688750..44560688750 100644
--- a/src/libsyntax/parse/classify.rs
+++ b/src/libsyntax/util/classify.rs
diff --git a/src/libsyntax/parse/lexer/comments.rs b/src/libsyntax/util/comments.rs
index ac79ce323bf..448b4f3b825 100644
--- a/src/libsyntax/parse/lexer/comments.rs
+++ b/src/libsyntax/util/comments.rs
@@ -2,13 +2,14 @@ pub use CommentStyle::*;
 
 use crate::ast;
 use crate::source_map::SourceMap;
-use crate::parse::lexer::is_block_doc_comment;
-use crate::parse::lexer::ParseSess;
+use crate::sess::ParseSess;
 
 use syntax_pos::{BytePos, CharPos, Pos, FileName};
 
 use std::usize;
 
+use log::debug;
+
 #[cfg(test)]
 mod tests;
 
@@ -31,8 +32,23 @@ pub struct Comment {
     pub pos: BytePos,
 }
 
-fn is_doc_comment(s: &str) -> bool {
-    (s.starts_with("///") && super::is_doc_comment(s)) || s.starts_with("//!") ||
+crate 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 {
+    // 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;
+    debug!("is {:?} a doc comment? {}", s, res);
+    res
+}
+
+crate fn is_doc_comment(s: &str) -> bool {
+    (s.starts_with("///") && is_line_doc_comment(s)) || s.starts_with("//!") ||
     (s.starts_with("/**") && is_block_doc_comment(s)) || s.starts_with("/*!")
 }
 
diff --git a/src/libsyntax/parse/lexer/comments/tests.rs b/src/libsyntax/util/comments/tests.rs
index f9cd69fb50d..f9cd69fb50d 100644
--- a/src/libsyntax/parse/lexer/comments/tests.rs
+++ b/src/libsyntax/util/comments/tests.rs
diff --git a/src/libsyntax/parse/literal.rs b/src/libsyntax/util/literal.rs
index a8eeac59954..d4c9b7850c5 100644
--- a/src/libsyntax/parse/literal.rs
+++ b/src/libsyntax/util/literal.rs
@@ -1,8 +1,8 @@
 //! Code related to parsing literals.
 
 use crate::ast::{self, Lit, LitKind};
-use crate::parse::token::{self, Token};
 use crate::symbol::{kw, sym, Symbol};
+use crate::token::{self, Token};
 use crate::tokenstream::TokenTree;
 
 use log::debug;
diff --git a/src/libsyntax/util/parser.rs b/src/libsyntax/util/parser.rs
index 982755e8680..edb708d7e97 100644
--- a/src/libsyntax/util/parser.rs
+++ b/src/libsyntax/util/parser.rs
@@ -1,4 +1,4 @@
-use crate::parse::token::{self, Token, BinOpToken};
+use crate::token::{self, Token, BinOpToken};
 use crate::symbol::kw;
 use crate::ast::{self, BinOpKind};
 
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 117787d08c7..cfd160fd577 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -14,7 +14,7 @@
 //! those that are created by the expansion of a macro.
 
 use crate::ast::*;
-use crate::parse::token::Token;
+use crate::token::Token;
 use crate::tokenstream::{TokenTree, TokenStream};
 
 use syntax_pos::Span;