Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

17 files changed, 1225 insertions, 809 deletions

diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 848e142e5..63819a2f9 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -14,8 +14,6 @@ use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{edition::Edition, BytePos, Pos, Span};
 
-use tracing::debug;
-
 mod tokentrees;
 mod unescape_error_reporting;
 mod unicode_chars;
diff --git a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
index 273827864..77c4fadab 100644
--- a/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
+++ b/compiler/rustc_parse/src/lexer/unescape_error_reporting.rs
@@ -20,13 +20,9 @@ pub(crate) fn emit_unescape_error(
     range: Range<usize>,
     error: EscapeError,
 ) {
-    tracing::debug!(
+    debug!(
         "emit_unescape_error: {:?}, {:?}, {:?}, {:?}, {:?}",
-        lit,
-        span_with_quotes,
-        mode,
-        range,
-        error
+        lit, span_with_quotes, mode, range, error
     );
     let last_char = || {
         let c = lit[range.clone()].chars().rev().next().unwrap();
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 8c087c65c..a37327f42 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -4,7 +4,7 @@
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
 #![recursion_limit = "256"]
@@ -63,7 +63,7 @@ pub fn parse_crate_from_file<'a>(input: &Path, sess: &'a ParseSess) -> PResult<'
 pub fn parse_crate_attrs_from_file<'a>(
     input: &Path,
     sess: &'a ParseSess,
-) -> PResult<'a, Vec<ast::Attribute>> {
+) -> PResult<'a, ast::AttrVec> {
     let mut parser = new_parser_from_file(sess, input, None);
     parser.parse_inner_attributes()
 }
@@ -80,7 +80,7 @@ pub fn parse_crate_attrs_from_source_str(
     name: FileName,
     source: String,
     sess: &ParseSess,
-) -> PResult<'_, Vec<ast::Attribute>> {
+) -> PResult<'_, ast::AttrVec> {
     new_parser_from_source_str(sess, name, source).parse_inner_attributes()
 }
 
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index acdbddf40..5fd69b15e 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -7,8 +7,6 @@ use rustc_errors::{error_code, Diagnostic, PResult};
 use rustc_span::{sym, BytePos, Span};
 use std::convert::TryInto;
 
-use tracing::debug;
-
 // Public for rustfmt usage
 #[derive(Debug)]
 pub enum InnerAttrPolicy<'a> {
@@ -34,7 +32,7 @@ enum OuterAttributeType {
 impl<'a> Parser<'a> {
     /// Parses attributes that appear before an item.
     pub(super) fn parse_outer_attributes(&mut self) -> PResult<'a, AttrWrapper> {
-        let mut outer_attrs: Vec<ast::Attribute> = Vec::new();
+        let mut outer_attrs = ast::AttrVec::new();
         let mut just_parsed_doc_comment = false;
         let start_pos = self.token_cursor.num_next_calls;
         loop {
@@ -89,6 +87,7 @@ impl<'a> Parser<'a> {
                 // Always make an outer attribute - this allows us to recover from a misplaced
                 // inner attribute.
                 Some(attr::mk_doc_comment(
+                    &self.sess.attr_id_generator,
                     comment_kind,
                     ast::AttrStyle::Outer,
                     data,
@@ -106,7 +105,7 @@ impl<'a> Parser<'a> {
                 break;
             }
         }
-        Ok(AttrWrapper::new(outer_attrs.into(), start_pos))
+        Ok(AttrWrapper::new(outer_attrs, start_pos))
     }
 
     /// Matches `attribute = # ! [ meta_item ]`.
@@ -140,7 +139,13 @@ impl<'a> Parser<'a> {
                     this.error_on_forbidden_inner_attr(attr_sp, inner_parse_policy);
                 }
 
-                Ok(attr::mk_attr_from_item(item, None, style, attr_sp))
+                Ok(attr::mk_attr_from_item(
+                    &self.sess.attr_id_generator,
+                    item,
+                    None,
+                    style,
+                    attr_sp,
+                ))
             } else {
                 let token_str = pprust::token_to_string(&this.token);
                 let msg = &format!("expected `#`, found `{token_str}`");
@@ -283,8 +288,8 @@ impl<'a> Parser<'a> {
     /// terminated by a semicolon.
     ///
     /// Matches `inner_attrs*`.
-    pub(crate) fn parse_inner_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
-        let mut attrs: Vec<ast::Attribute> = vec![];
+    pub(crate) fn parse_inner_attributes(&mut self) -> PResult<'a, ast::AttrVec> {
+        let mut attrs = ast::AttrVec::new();
         loop {
             let start_pos: u32 = self.token_cursor.num_next_calls.try_into().unwrap();
             // Only try to parse if it is an inner attribute (has `!`).
@@ -293,7 +298,13 @@ impl<'a> Parser<'a> {
             } else if let token::DocComment(comment_kind, attr_style, data) = self.token.kind {
                 if attr_style == ast::AttrStyle::Inner {
                     self.bump();
-                    Some(attr::mk_doc_comment(comment_kind, attr_style, data, self.prev_token.span))
+                    Some(attr::mk_doc_comment(
+                        &self.sess.attr_id_generator,
+                        comment_kind,
+                        attr_style,
+                        data,
+                        self.prev_token.span,
+                    ))
                 } else {
                     None
                 }
@@ -303,9 +314,9 @@ impl<'a> Parser<'a> {
             if let Some(attr) = attr {
                 let end_pos: u32 = self.token_cursor.num_next_calls.try_into().unwrap();
                 // If we are currently capturing tokens, mark the location of this inner attribute.
-                // If capturing ends up creating a `LazyTokenStream`, we will include
+                // If capturing ends up creating a `LazyAttrTokenStream`, we will include
                 // this replace range with it, removing the inner attribute from the final
-                // `AttrAnnotatedTokenStream`. Inner attributes are stored in the parsed AST note.
+                // `AttrTokenStream`. Inner attributes are stored in the parsed AST note.
                 // During macro expansion, they are selectively inserted back into the
                 // token stream (the first inner attribute is removed each time we invoke the
                 // corresponding macro).
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index 6c750ff42..5fdafd187 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -1,7 +1,7 @@
 use super::{Capturing, FlatToken, ForceCollect, Parser, ReplaceRange, TokenCursor, TrailingToken};
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
-use rustc_ast::tokenstream::{AttrAnnotatedTokenStream, AttributesData, CreateTokenStream};
-use rustc_ast::tokenstream::{AttrAnnotatedTokenTree, DelimSpan, LazyTokenStream, Spacing};
+use rustc_ast::tokenstream::{AttrTokenStream, AttributesData, ToAttrTokenStream};
+use rustc_ast::tokenstream::{AttrTokenTree, DelimSpan, LazyAttrTokenStream, Spacing};
 use rustc_ast::{self as ast};
 use rustc_ast::{AttrVec, Attribute, HasAttrs, HasTokens};
 use rustc_errors::PResult;
@@ -15,11 +15,11 @@ use std::ops::Range;
 /// for the attribute target. This allows us to perform cfg-expansion on
 /// a token stream before we invoke a derive proc-macro.
 ///
-/// This wrapper prevents direct access to the underlying `Vec<ast::Attribute>`.
+/// This wrapper prevents direct access to the underlying `ast::AttrVec>`.
 /// Parsing code can only get access to the underlying attributes
 /// by passing an `AttrWrapper` to `collect_tokens_trailing_tokens`.
 /// This makes it difficult to accidentally construct an AST node
-/// (which stores a `Vec<ast::Attribute>`) without first collecting tokens.
+/// (which stores an `ast::AttrVec`) without first collecting tokens.
 ///
 /// This struct has its own module, to ensure that the parser code
 /// cannot directly access the `attrs` field
@@ -49,9 +49,10 @@ impl AttrWrapper {
         self.attrs
     }
 
+    // Prepend `self.attrs` to `attrs`.
     // FIXME: require passing an NT to prevent misuse of this method
-    pub(crate) fn prepend_to_nt_inner(self, attrs: &mut Vec<Attribute>) {
-        let mut self_attrs: Vec<_> = self.attrs.into();
+    pub(crate) fn prepend_to_nt_inner(self, attrs: &mut AttrVec) {
+        let mut self_attrs = self.attrs;
         std::mem::swap(attrs, &mut self_attrs);
         attrs.extend(self_attrs);
     }
@@ -87,7 +88,7 @@ fn has_cfg_or_cfg_attr(attrs: &[Attribute]) -> bool {
 // This also makes `Parser` very cheap to clone, since
 // there is no intermediate collection buffer to clone.
 #[derive(Clone)]
-struct LazyTokenStreamImpl {
+struct LazyAttrTokenStreamImpl {
     start_token: (Token, Spacing),
     cursor_snapshot: TokenCursor,
     num_calls: usize,
@@ -96,10 +97,10 @@ struct LazyTokenStreamImpl {
 }
 
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(LazyTokenStreamImpl, 144);
+rustc_data_structures::static_assert_size!(LazyAttrTokenStreamImpl, 144);
 
-impl CreateTokenStream for LazyTokenStreamImpl {
-    fn create_token_stream(&self) -> AttrAnnotatedTokenStream {
+impl ToAttrTokenStream for LazyAttrTokenStreamImpl {
+    fn to_attr_token_stream(&self) -> AttrTokenStream {
         // The token produced by the final call to `{,inlined_}next` was not
         // actually consumed by the callback. The combination of chaining the
         // initial token and using `take` produces the desired result - we
@@ -116,7 +117,7 @@ impl CreateTokenStream for LazyTokenStreamImpl {
 
         if !self.replace_ranges.is_empty() {
             let mut tokens: Vec<_> = tokens.collect();
-            let mut replace_ranges = self.replace_ranges.clone();
+            let mut replace_ranges = self.replace_ranges.to_vec();
             replace_ranges.sort_by_key(|(range, _)| range.start);
 
             #[cfg(debug_assertions)]
@@ -146,7 +147,7 @@ impl CreateTokenStream for LazyTokenStreamImpl {
             // start position, we ensure that any replace range which encloses
             // another replace range will capture the *replaced* tokens for the inner
             // range, not the original tokens.
-            for (range, new_tokens) in replace_ranges.iter().rev() {
+            for (range, new_tokens) in replace_ranges.into_iter().rev() {
                 assert!(!range.is_empty(), "Cannot replace an empty range: {:?}", range);
                 // Replace ranges are only allowed to decrease the number of tokens.
                 assert!(
@@ -165,7 +166,7 @@ impl CreateTokenStream for LazyTokenStreamImpl {
 
                 tokens.splice(
                     (range.start as usize)..(range.end as usize),
-                    new_tokens.clone().into_iter().chain(filler),
+                    new_tokens.into_iter().chain(filler),
                 );
             }
             make_token_stream(tokens.into_iter(), self.break_last_token)
@@ -178,7 +179,7 @@ impl CreateTokenStream for LazyTokenStreamImpl {
 impl<'a> Parser<'a> {
     /// Records all tokens consumed by the provided callback,
     /// including the current token. These tokens are collected
-    /// into a `LazyTokenStream`, and returned along with the result
+    /// into a `LazyAttrTokenStream`, and returned along with the result
     /// of the callback.
     ///
     /// Note: If your callback consumes an opening delimiter
@@ -196,7 +197,7 @@ impl<'a> Parser<'a> {
         &mut self,
         attrs: AttrWrapper,
         force_collect: ForceCollect,
-        f: impl FnOnce(&mut Self, Vec<ast::Attribute>) -> PResult<'a, (R, TrailingToken)>,
+        f: impl FnOnce(&mut Self, ast::AttrVec) -> PResult<'a, (R, TrailingToken)>,
     ) -> PResult<'a, R> {
         // We only bail out when nothing could possibly observe the collected tokens:
         // 1. We cannot be force collecting tokens (since force-collecting requires tokens
@@ -212,7 +213,7 @@ impl<'a> Parser<'a> {
             // or `#[cfg_attr]` attributes.
             && !self.capture_cfg
         {
-            return Ok(f(self, attrs.attrs.into())?.0);
+            return Ok(f(self, attrs.attrs)?.0);
         }
 
         let start_token = (self.token.clone(), self.token_spacing);
@@ -222,7 +223,7 @@ impl<'a> Parser<'a> {
         let prev_capturing = std::mem::replace(&mut self.capture_state.capturing, Capturing::Yes);
         let replace_ranges_start = self.capture_state.replace_ranges.len();
 
-        let ret = f(self, attrs.attrs.into());
+        let ret = f(self, attrs.attrs);
 
         self.capture_state.capturing = prev_capturing;
 
@@ -296,8 +297,8 @@ impl<'a> Parser<'a> {
 
         // If we 'broke' the last token (e.g. breaking a '>>' token to two '>' tokens),
         // then extend the range of captured tokens to include it, since the parser
-        // was not actually bumped past it. When the `LazyTokenStream` gets converted
-        // into an `AttrAnnotatedTokenStream`, we will create the proper token.
+        // was not actually bumped past it. When the `LazyAttrTokenStream` gets converted
+        // into an `AttrTokenStream`, we will create the proper token.
         if self.token_cursor.break_last_token {
             assert_eq!(
                 trailing,
@@ -315,20 +316,20 @@ impl<'a> Parser<'a> {
             Box::new([])
         } else {
             // Grab any replace ranges that occur *inside* the current AST node.
-            // We will perform the actual replacement when we convert the `LazyTokenStream`
-            // to an `AttrAnnotatedTokenStream`
+            // We will perform the actual replacement when we convert the `LazyAttrTokenStream`
+            // to an `AttrTokenStream`.
             let start_calls: u32 = cursor_snapshot_next_calls.try_into().unwrap();
             self.capture_state.replace_ranges[replace_ranges_start..replace_ranges_end]
                 .iter()
                 .cloned()
-                .chain(inner_attr_replace_ranges.clone().into_iter())
+                .chain(inner_attr_replace_ranges.iter().cloned())
                 .map(|(range, tokens)| {
                     ((range.start - start_calls)..(range.end - start_calls), tokens)
                 })
                 .collect()
         };
 
-        let tokens = LazyTokenStream::new(LazyTokenStreamImpl {
+        let tokens = LazyAttrTokenStream::new(LazyAttrTokenStreamImpl {
             start_token,
             num_calls,
             cursor_snapshot,
@@ -352,9 +353,9 @@ impl<'a> Parser<'a> {
         // on the captured token stream.
         if self.capture_cfg
             && matches!(self.capture_state.capturing, Capturing::Yes)
-            && has_cfg_or_cfg_attr(&final_attrs)
+            && has_cfg_or_cfg_attr(final_attrs)
         {
-            let attr_data = AttributesData { attrs: final_attrs.to_vec().into(), tokens };
+            let attr_data = AttributesData { attrs: final_attrs.iter().cloned().collect(), tokens };
 
             // Replace the entire AST node that we just parsed, including attributes,
             // with a `FlatToken::AttrTarget`. If this AST node is inside an item
@@ -391,12 +392,12 @@ impl<'a> Parser<'a> {
 fn make_token_stream(
     mut iter: impl Iterator<Item = (FlatToken, Spacing)>,
     break_last_token: bool,
-) -> AttrAnnotatedTokenStream {
+) -> AttrTokenStream {
     #[derive(Debug)]
     struct FrameData {
         // This is `None` for the first frame, `Some` for all others.
         open_delim_sp: Option<(Delimiter, Span)>,
-        inner: Vec<(AttrAnnotatedTokenTree, Spacing)>,
+        inner: Vec<AttrTokenTree>,
     }
     let mut stack = vec![FrameData { open_delim_sp: None, inner: vec![] }];
     let mut token_and_spacing = iter.next();
@@ -417,48 +418,47 @@ fn make_token_stream(
                     open_delim, span
                 );
                 let dspan = DelimSpan::from_pair(open_sp, span);
-                let stream = AttrAnnotatedTokenStream::new(frame_data.inner);
-                let delimited = AttrAnnotatedTokenTree::Delimited(dspan, delim, stream);
+                let stream = AttrTokenStream::new(frame_data.inner);
+                let delimited = AttrTokenTree::Delimited(dspan, delim, stream);
                 stack
                     .last_mut()
                     .unwrap_or_else(|| {
                         panic!("Bottom token frame is missing for token: {:?}", token)
                     })
                     .inner
-                    .push((delimited, Spacing::Alone));
+                    .push(delimited);
             }
             FlatToken::Token(token) => stack
                 .last_mut()
                 .expect("Bottom token frame is missing!")
                 .inner
-                .push((AttrAnnotatedTokenTree::Token(token), spacing)),
+                .push(AttrTokenTree::Token(token, spacing)),
             FlatToken::AttrTarget(data) => stack
                 .last_mut()
                 .expect("Bottom token frame is missing!")
                 .inner
-                .push((AttrAnnotatedTokenTree::Attributes(data), spacing)),
+                .push(AttrTokenTree::Attributes(data)),
             FlatToken::Empty => {}
         }
         token_and_spacing = iter.next();
     }
     let mut final_buf = stack.pop().expect("Missing final buf!");
     if break_last_token {
-        let (last_token, spacing) = final_buf.inner.pop().unwrap();
-        if let AttrAnnotatedTokenTree::Token(last_token) = last_token {
+        let last_token = final_buf.inner.pop().unwrap();
+        if let AttrTokenTree::Token(last_token, spacing) = last_token {
             let unglued_first = last_token.kind.break_two_token_op().unwrap().0;
 
             // An 'unglued' token is always two ASCII characters
             let mut first_span = last_token.span.shrink_to_lo();
             first_span = first_span.with_hi(first_span.lo() + rustc_span::BytePos(1));
 
-            final_buf.inner.push((
-                AttrAnnotatedTokenTree::Token(Token::new(unglued_first, first_span)),
-                spacing,
-            ));
+            final_buf
+                .inner
+                .push(AttrTokenTree::Token(Token::new(unglued_first, first_span), spacing));
         } else {
             panic!("Unexpected last token {:?}", last_token)
         }
     }
     assert!(stack.is_empty(), "Stack should be empty: final_buf={:?} stack={:?}", final_buf, stack);
-    AttrAnnotatedTokenStream::new(final_buf.inner)
+    AttrTokenStream::new(final_buf.inner)
 }
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index a2155ac1d..be524db78 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -10,26 +10,25 @@ use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, Lit, LitKind, TokenKind};
 use rustc_ast::util::parser::AssocOp;
 use rustc_ast::{
-    AngleBracketedArg, AngleBracketedArgs, AnonConst, AttrVec, BinOpKind, BindingMode, Block,
-    BlockCheckMode, Expr, ExprKind, GenericArg, Generics, Item, ItemKind, Mutability, Param, Pat,
-    PatKind, Path, PathSegment, QSelf, Ty, TyKind,
+    AngleBracketedArg, AngleBracketedArgs, AnonConst, AttrVec, BinOpKind, BindingAnnotation, Block,
+    BlockCheckMode, Expr, ExprKind, GenericArg, Generics, Item, ItemKind, Param, Pat, PatKind,
+    Path, PathSegment, QSelf, Ty, TyKind,
 };
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{
     fluent, Applicability, DiagnosticBuilder, DiagnosticMessage, Handler, MultiSpan, PResult,
 };
-use rustc_errors::{pluralize, struct_span_err, Diagnostic, EmissionGuarantee, ErrorGuaranteed};
+use rustc_errors::{pluralize, struct_span_err, Diagnostic, ErrorGuaranteed};
 use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{kw, Ident};
+use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{Span, SpanSnippetError, DUMMY_SP};
 use std::ops::{Deref, DerefMut};
 
 use std::mem::take;
 
 use crate::parser;
-use tracing::{debug, trace};
 
 const TURBOFISH_SUGGESTION_STR: &str =
     "use `::<...>` instead of `<...>` to specify lifetime, type, or const arguments";
@@ -38,7 +37,7 @@ const TURBOFISH_SUGGESTION_STR: &str =
 pub(super) fn dummy_arg(ident: Ident) -> Param {
     let pat = P(Pat {
         id: ast::DUMMY_NODE_ID,
-        kind: PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None),
+        kind: PatKind::Ident(BindingAnnotation::NONE, ident, None),
         span: ident.span,
         tokens: None,
     });
@@ -228,13 +227,13 @@ struct MultiSugg {
 }
 
 impl MultiSugg {
-    fn emit<G: EmissionGuarantee>(self, err: &mut DiagnosticBuilder<'_, G>) {
+    fn emit(self, err: &mut Diagnostic) {
         err.multipart_suggestion(&self.msg, self.patches, self.applicability);
     }
 
     /// Overrides individual messages and applicabilities.
-    fn emit_many<G: EmissionGuarantee>(
-        err: &mut DiagnosticBuilder<'_, G>,
+    fn emit_many(
+        err: &mut Diagnostic,
         msg: &str,
         applicability: Applicability,
         suggestions: impl Iterator<Item = Self>,
@@ -244,7 +243,7 @@ impl MultiSugg {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::maybe_report_ambiguous_plus)]
+#[diag(parser::maybe_report_ambiguous_plus)]
 struct AmbiguousPlus {
     pub sum_ty: String,
     #[primary_span]
@@ -253,7 +252,7 @@ struct AmbiguousPlus {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::maybe_recover_from_bad_type_plus, code = "E0178")]
+#[diag(parser::maybe_recover_from_bad_type_plus, code = "E0178")]
 struct BadTypePlus {
     pub ty: String,
     #[primary_span]
@@ -287,7 +286,7 @@ pub enum BadTypePlusSub {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::maybe_recover_from_bad_qpath_stage_2)]
+#[diag(parser::maybe_recover_from_bad_qpath_stage_2)]
 struct BadQPathStage2 {
     #[primary_span]
     #[suggestion(applicability = "maybe-incorrect")]
@@ -296,7 +295,7 @@ struct BadQPathStage2 {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::incorrect_semicolon)]
+#[diag(parser::incorrect_semicolon)]
 struct IncorrectSemicolon<'a> {
     #[primary_span]
     #[suggestion_short(applicability = "machine-applicable")]
@@ -307,7 +306,7 @@ struct IncorrectSemicolon<'a> {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::incorrect_use_of_await)]
+#[diag(parser::incorrect_use_of_await)]
 struct IncorrectUseOfAwait {
     #[primary_span]
     #[suggestion(parser::parentheses_suggestion, applicability = "machine-applicable")]
@@ -315,7 +314,7 @@ struct IncorrectUseOfAwait {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::incorrect_use_of_await)]
+#[diag(parser::incorrect_use_of_await)]
 struct IncorrectAwait {
     #[primary_span]
     span: Span,
@@ -326,7 +325,7 @@ struct IncorrectAwait {
 }
 
 #[derive(SessionDiagnostic)]
-#[error(parser::in_in_typo)]
+#[diag(parser::in_in_typo)]
 struct InInTypo {
     #[primary_span]
     span: Span,
@@ -334,6 +333,394 @@ struct InInTypo {
     sugg_span: Span,
 }
 
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_variable_declaration)]
+pub struct InvalidVariableDeclaration {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub sub: InvalidVariableDeclarationSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub enum InvalidVariableDeclarationSub {
+    #[suggestion(
+        parser::switch_mut_let_order,
+        applicability = "maybe-incorrect",
+        code = "let mut"
+    )]
+    SwitchMutLetOrder(#[primary_span] Span),
+    #[suggestion(
+        parser::missing_let_before_mut,
+        applicability = "machine-applicable",
+        code = "let mut"
+    )]
+    MissingLet(#[primary_span] Span),
+    #[suggestion(parser::use_let_not_auto, applicability = "machine-applicable", code = "let")]
+    UseLetNotAuto(#[primary_span] Span),
+    #[suggestion(parser::use_let_not_var, applicability = "machine-applicable", code = "let")]
+    UseLetNotVar(#[primary_span] Span),
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_comparison_operator)]
+pub(crate) struct InvalidComparisonOperator {
+    #[primary_span]
+    pub span: Span,
+    pub invalid: String,
+    #[subdiagnostic]
+    pub sub: InvalidComparisonOperatorSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum InvalidComparisonOperatorSub {
+    #[suggestion_short(
+        parser::use_instead,
+        applicability = "machine-applicable",
+        code = "{correct}"
+    )]
+    Correctable {
+        #[primary_span]
+        span: Span,
+        invalid: String,
+        correct: String,
+    },
+    #[label(parser::spaceship_operator_invalid)]
+    Spaceship(#[primary_span] Span),
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_logical_operator)]
+#[note]
+pub(crate) struct InvalidLogicalOperator {
+    #[primary_span]
+    pub span: Span,
+    pub incorrect: String,
+    #[subdiagnostic]
+    pub sub: InvalidLogicalOperatorSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum InvalidLogicalOperatorSub {
+    #[suggestion_short(
+        parser::use_amp_amp_for_conjunction,
+        applicability = "machine-applicable",
+        code = "&&"
+    )]
+    Conjunction(#[primary_span] Span),
+    #[suggestion_short(
+        parser::use_pipe_pipe_for_disjunction,
+        applicability = "machine-applicable",
+        code = "||"
+    )]
+    Disjunction(#[primary_span] Span),
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::tilde_is_not_unary_operator)]
+pub(crate) struct TildeAsUnaryOperator(
+    #[primary_span]
+    #[suggestion_short(applicability = "machine-applicable", code = "!")]
+    pub Span,
+);
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::unexpected_token_after_not)]
+pub(crate) struct NotAsNegationOperator {
+    #[primary_span]
+    pub negated: Span,
+    pub negated_desc: String,
+    #[suggestion_short(applicability = "machine-applicable", code = "!")]
+    pub not: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::malformed_loop_label)]
+pub(crate) struct MalformedLoopLabel {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "{correct_label}")]
+    pub span: Span,
+    pub correct_label: Ident,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::lifetime_in_borrow_expression)]
+pub(crate) struct LifetimeInBorrowExpression {
+    #[primary_span]
+    pub span: Span,
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    #[label]
+    pub lifetime_span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::field_expression_with_generic)]
+pub(crate) struct FieldExpressionWithGeneric(#[primary_span] pub Span);
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::macro_invocation_with_qualified_path)]
+pub(crate) struct MacroInvocationWithQualifiedPath(#[primary_span] pub Span);
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::unexpected_token_after_label)]
+pub(crate) struct UnexpectedTokenAfterLabel(
+    #[primary_span]
+    #[label(parser::unexpected_token_after_label)]
+    pub Span,
+);
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::require_colon_after_labeled_expression)]
+#[note]
+pub(crate) struct RequireColonAfterLabeledExpression {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub label: Span,
+    #[suggestion_short(applicability = "machine-applicable", code = ": ")]
+    pub label_end: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::do_catch_syntax_removed)]
+#[note]
+pub(crate) struct DoCatchSyntaxRemoved {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "try")]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::float_literal_requires_integer_part)]
+pub(crate) struct FloatLiteralRequiresIntegerPart {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "{correct}")]
+    pub span: Span,
+    pub correct: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_int_literal_width)]
+#[help]
+pub(crate) struct InvalidIntLiteralWidth {
+    #[primary_span]
+    pub span: Span,
+    pub width: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_num_literal_base_prefix)]
+#[note]
+pub(crate) struct InvalidNumLiteralBasePrefix {
+    #[primary_span]
+    #[suggestion(applicability = "maybe-incorrect", code = "{fixed}")]
+    pub span: Span,
+    pub fixed: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_num_literal_suffix)]
+#[help]
+pub(crate) struct InvalidNumLiteralSuffix {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub suffix: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_float_literal_width)]
+#[help]
+pub(crate) struct InvalidFloatLiteralWidth {
+    #[primary_span]
+    pub span: Span,
+    pub width: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_float_literal_suffix)]
+#[help]
+pub(crate) struct InvalidFloatLiteralSuffix {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub suffix: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::int_literal_too_large)]
+pub(crate) struct IntLiteralTooLarge {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::missing_semicolon_before_array)]
+pub(crate) struct MissingSemicolonBeforeArray {
+    #[primary_span]
+    pub open_delim: Span,
+    #[suggestion_verbose(applicability = "maybe-incorrect", code = ";")]
+    pub semicolon: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::invalid_block_macro_segment)]
+pub(crate) struct InvalidBlockMacroSegment {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub context: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::if_expression_missing_then_block)]
+pub(crate) struct IfExpressionMissingThenBlock {
+    #[primary_span]
+    pub if_span: Span,
+    #[subdiagnostic]
+    pub sub: IfExpressionMissingThenBlockSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum IfExpressionMissingThenBlockSub {
+    #[help(parser::condition_possibly_unfinished)]
+    UnfinishedCondition(#[primary_span] Span),
+    #[help(parser::add_then_block)]
+    AddThenBlock(#[primary_span] Span),
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::if_expression_missing_condition)]
+pub(crate) struct IfExpressionMissingCondition {
+    #[primary_span]
+    #[label(parser::condition_label)]
+    pub if_span: Span,
+    #[label(parser::block_label)]
+    pub block_span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::expected_expression_found_let)]
+pub(crate) struct ExpectedExpressionFoundLet {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::expected_else_block)]
+pub(crate) struct ExpectedElseBlock {
+    #[primary_span]
+    pub first_tok_span: Span,
+    pub first_tok: String,
+    #[label]
+    pub else_span: Span,
+    #[suggestion(applicability = "maybe-incorrect", code = "if ")]
+    pub condition_start: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::outer_attribute_not_allowed_on_if_else)]
+pub(crate) struct OuterAttributeNotAllowedOnIfElse {
+    #[primary_span]
+    pub last: Span,
+
+    #[label(parser::branch_label)]
+    pub branch_span: Span,
+
+    #[label(parser::ctx_label)]
+    pub ctx_span: Span,
+    pub ctx: String,
+
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    pub attributes: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::missing_in_in_for_loop)]
+pub(crate) struct MissingInInForLoop {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub sub: MissingInInForLoopSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum MissingInInForLoopSub {
+    // Has been misleading, at least in the past (closed Issue #48492), thus maybe-incorrect
+    #[suggestion_short(parser::use_in_not_of, applicability = "maybe-incorrect", code = "in")]
+    InNotOf(#[primary_span] Span),
+    #[suggestion_short(parser::add_in, applicability = "maybe-incorrect", code = " in ")]
+    AddIn(#[primary_span] Span),
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::missing_comma_after_match_arm)]
+pub(crate) struct MissingCommaAfterMatchArm {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = ",")]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::catch_after_try)]
+#[help]
+pub(crate) struct CatchAfterTry {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::comma_after_base_struct)]
+#[note]
+pub(crate) struct CommaAfterBaseStruct {
+    #[primary_span]
+    pub span: Span,
+    #[suggestion_short(applicability = "machine-applicable", code = "")]
+    pub comma: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::eq_field_init)]
+pub(crate) struct EqFieldInit {
+    #[primary_span]
+    pub span: Span,
+    #[suggestion(applicability = "machine-applicable", code = ":")]
+    pub eq: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::dotdotdot)]
+pub(crate) struct DotDotDot {
+    #[primary_span]
+    #[suggestion(parser::suggest_exclusive_range, applicability = "maybe-incorrect", code = "..")]
+    #[suggestion(parser::suggest_inclusive_range, applicability = "maybe-incorrect", code = "..=")]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::left_arrow_operator)]
+pub(crate) struct LeftArrowOperator {
+    #[primary_span]
+    #[suggestion(applicability = "maybe-incorrect", code = "< -")]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::remove_let)]
+pub(crate) struct RemoveLet {
+    #[primary_span]
+    #[suggestion(applicability = "machine-applicable", code = "")]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(parser::use_eq_instead)]
+pub(crate) struct UseEqInstead {
+    #[primary_span]
+    #[suggestion_short(applicability = "machine-applicable", code = "=")]
+    pub span: Span,
+}
+
 // SnapshotParser is used to create a snapshot of the parser
 // without causing duplicate errors being emitted when the `Parser`
 // is dropped.
@@ -387,7 +774,7 @@ impl<'a> Parser<'a> {
     /// This is to avoid losing unclosed delims errors `create_snapshot_for_diagnostic` clears.
     pub(super) fn restore_snapshot(&mut self, snapshot: SnapshotParser<'a>) {
         *self = snapshot.parser;
-        self.unclosed_delims.extend(snapshot.unclosed_delims.clone());
+        self.unclosed_delims.extend(snapshot.unclosed_delims);
     }
 
     pub fn unclosed_delims(&self) -> &[UnmatchedBrace] {
@@ -555,10 +942,12 @@ impl<'a> Parser<'a> {
                 return Ok(true);
             } else if self.look_ahead(0, |t| {
                 t == &token::CloseDelim(Delimiter::Brace)
-                    || (t.can_begin_expr() && t != &token::Semi && t != &token::Pound)
+                    || ((t.can_begin_expr() || t.can_begin_item())
+                        && t != &token::Semi
+                        && t != &token::Pound)
                     // Avoid triggering with too many trailing `#` in raw string.
                     || (sm.is_multiline(
-                        self.prev_token.span.shrink_to_hi().until(self.token.span.shrink_to_lo())
+                        self.prev_token.span.shrink_to_hi().until(self.token.span.shrink_to_lo()),
                     ) && t == &token::Pound)
             }) && !expected.contains(&TokenType::Token(token::Comma))
             {
@@ -576,6 +965,14 @@ impl<'a> Parser<'a> {
             }
         }
 
+        if self.token.kind == TokenKind::EqEq
+            && self.prev_token.is_ident()
+            && expected.iter().any(|tok| matches!(tok, TokenType::Token(TokenKind::Eq)))
+        {
+            // Likely typo: `=` → `==` in let expr or enum item
+            return Err(self.sess.create_err(UseEqInstead { span: self.token.span }));
+        }
+
         let expect = tokens_to_string(&expected);
         let actual = super::token_descr(&self.token);
         let (msg_exp, (label_sp, label_exp)) = if expected.len() > 1 {
@@ -590,7 +987,7 @@ impl<'a> Parser<'a> {
             )
         } else if expected.is_empty() {
             (
-                format!("unexpected token: {}", actual),
+                format!("unexpected token: {actual}"),
                 (self.prev_token.span, "unexpected token after this".to_string()),
             )
         } else {
@@ -603,16 +1000,29 @@ impl<'a> Parser<'a> {
         let mut err = self.struct_span_err(self.token.span, &msg_exp);
 
         if let TokenKind::Ident(symbol, _) = &self.prev_token.kind {
-            if symbol.as_str() == "public" {
+            if ["def", "fun", "func", "function"].contains(&symbol.as_str()) {
                 err.span_suggestion_short(
                     self.prev_token.span,
-                    "write `pub` instead of `public` to make the item public",
-                    "pub",
+                    &format!("write `fn` instead of `{symbol}` to declare a function"),
+                    "fn",
                     appl,
                 );
             }
         }
 
+        // `pub` may be used for an item or `pub(crate)`
+        if self.prev_token.is_ident_named(sym::public)
+            && (self.token.can_begin_item()
+                || self.token.kind == TokenKind::OpenDelim(Delimiter::Parenthesis))
+        {
+            err.span_suggestion_short(
+                self.prev_token.span,
+                "write `pub` instead of `public` to make the item public",
+                "pub",
+                appl,
+            );
+        }
+
         // Add suggestion for a missing closing angle bracket if '>' is included in expected_tokens
         // there are unclosed angle brackets
         if self.unmatched_angle_bracket_count > 0
@@ -734,7 +1144,7 @@ impl<'a> Parser<'a> {
             let mut snapshot = self.create_snapshot_for_diagnostic();
             let path =
                 Path { segments: vec![], span: self.prev_token.span.shrink_to_lo(), tokens: None };
-            let struct_expr = snapshot.parse_struct_expr(None, path, AttrVec::new(), false);
+            let struct_expr = snapshot.parse_struct_expr(None, path, false);
             let block_tail = self.parse_block_tail(lo, s, AttemptLocalParseRecovery::No);
             return Some(match (struct_expr, block_tail) {
                 (Ok(expr), Err(mut err)) => {
@@ -1188,8 +1598,7 @@ impl<'a> Parser<'a> {
             outer_op.node,
         );
 
-        let mk_err_expr =
-            |this: &Self, span| Ok(Some(this.mk_expr(span, ExprKind::Err, AttrVec::new())));
+        let mk_err_expr = |this: &Self, span| Ok(Some(this.mk_expr(span, ExprKind::Err)));
 
         match inner_op.kind {
             ExprKind::Binary(op, ref l1, ref r1) if op.node.is_comparison() => {
@@ -1497,7 +1906,7 @@ impl<'a> Parser<'a> {
         MultiSugg {
             msg: format!("use `{}= 1` instead", kind.op.chr()),
             patches: vec![
-                (pre_span, format!("{{ let {} = ", tmp_var)),
+                (pre_span, format!("{{ let {tmp_var} = ")),
                 (post_span, format!("; {} {}= 1; {} }}", base_src, kind.op.chr(), tmp_var)),
             ],
             applicability: Applicability::HasPlaceholders,
@@ -1647,7 +2056,6 @@ impl<'a> Parser<'a> {
         &mut self,
         lo: Span,
         await_sp: Span,
-        attrs: AttrVec,
     ) -> PResult<'a, P<Expr>> {
         let (hi, expr, is_question) = if self.token == token::Not {
             // Handle `await!(<expr>)`.
@@ -1662,7 +2070,7 @@ impl<'a> Parser<'a> {
             ExprKind::Try(_) => ExprKind::Err,
             _ => ExprKind::Await(expr),
         };
-        let expr = self.mk_expr(lo.to(sp), kind, attrs);
+        let expr = self.mk_expr(lo.to(sp), kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
@@ -1680,7 +2088,7 @@ impl<'a> Parser<'a> {
             // Handle `await { <expr> }`.
             // This needs to be handled separately from the next arm to avoid
             // interpreting `await { <expr> }?` as `<expr>?.await`.
-            self.parse_block_expr(None, self.token.span, BlockCheckMode::Default, AttrVec::new())
+            self.parse_block_expr(None, self.token.span, BlockCheckMode::Default)
         } else {
             self.parse_expr()
         }
@@ -1823,7 +2231,7 @@ impl<'a> Parser<'a> {
                 err.emit();
                 // Recover from parse error, callers expect the closing delim to be consumed.
                 self.consume_block(delim, ConsumeClosingDelim::Yes);
-                self.mk_expr(lo.to(self.prev_token.span), ExprKind::Err, AttrVec::new())
+                self.mk_expr(lo.to(self.prev_token.span), ExprKind::Err)
             }
         }
     }
@@ -2334,7 +2742,7 @@ impl<'a> Parser<'a> {
 
     fn recover_const_param_decl(&mut self, ty_generics: Option<&Generics>) -> Option<GenericArg> {
         let snapshot = self.create_snapshot_for_diagnostic();
-        let param = match self.parse_const_param(vec![]) {
+        let param = match self.parse_const_param(AttrVec::new()) {
             Ok(param) => param,
             Err(err) => {
                 err.cancel();
@@ -2577,7 +2985,7 @@ impl<'a> Parser<'a> {
                                 }
                                 _ => {}
                             },
-                            PatKind::Ident(BindingMode::ByValue(Mutability::Not), ident, None) => {
+                            PatKind::Ident(BindingAnnotation::NONE, ident, None) => {
                                 match &first_pat.kind {
                                     PatKind::Ident(_, old_ident, _) => {
                                         let path = PatKind::Path(
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 0719a0ef0..725768c1f 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1,4 +1,14 @@
-use super::diagnostics::SnapshotParser;
+use super::diagnostics::{
+    CatchAfterTry, CommaAfterBaseStruct, DoCatchSyntaxRemoved, DotDotDot, EqFieldInit,
+    ExpectedElseBlock, ExpectedExpressionFoundLet, FieldExpressionWithGeneric,
+    FloatLiteralRequiresIntegerPart, IfExpressionMissingCondition, IfExpressionMissingThenBlock,
+    IfExpressionMissingThenBlockSub, InvalidBlockMacroSegment, InvalidComparisonOperator,
+    InvalidComparisonOperatorSub, InvalidLogicalOperator, InvalidLogicalOperatorSub,
+    LeftArrowOperator, LifetimeInBorrowExpression, MacroInvocationWithQualifiedPath,
+    MalformedLoopLabel, MissingInInForLoop, MissingInInForLoopSub, MissingSemicolonBeforeArray,
+    NotAsNegationOperator, OuterAttributeNotAllowedOnIfElse, RequireColonAfterLabeledExpression,
+    SnapshotParser, TildeAsUnaryOperator, UnexpectedTokenAfterLabel,
+};
 use super::pat::{CommaRecoveryMode, RecoverColon, RecoverComma, PARAM_EXPECTED};
 use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
 use super::{
@@ -6,6 +16,11 @@ use super::{
     SemiColonMode, SeqSep, TokenExpectType, TokenType, TrailingToken,
 };
 use crate::maybe_recover_from_interpolated_ty_qpath;
+use crate::parser::diagnostics::{
+    IntLiteralTooLarge, InvalidFloatLiteralSuffix, InvalidFloatLiteralWidth,
+    InvalidIntLiteralWidth, InvalidNumLiteralBasePrefix, InvalidNumLiteralSuffix,
+    MissingCommaAfterMatchArm,
+};
 
 use core::mem;
 use rustc_ast::ptr::P;
@@ -20,10 +35,10 @@ use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty
 use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
 use rustc_ast::{ClosureBinder, StmtKind};
 use rustc_ast_pretty::pprust;
-use rustc_data_structures::thin_vec::ThinVec;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, PResult};
+use rustc_errors::{Applicability, Diagnostic, PResult};
 use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
 use rustc_session::lint::BuiltinLintDiagnostics;
+use rustc_session::SessionDiagnostic;
 use rustc_span::source_map::{self, Span, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Pos};
@@ -45,20 +60,12 @@ macro_rules! maybe_whole_expr {
                 token::NtPath(path) => {
                     let path = (**path).clone();
                     $p.bump();
-                    return Ok($p.mk_expr(
-                        $p.prev_token.span,
-                        ExprKind::Path(None, path),
-                        AttrVec::new(),
-                    ));
+                    return Ok($p.mk_expr($p.prev_token.span, ExprKind::Path(None, path)));
                 }
                 token::NtBlock(block) => {
                     let block = block.clone();
                     $p.bump();
-                    return Ok($p.mk_expr(
-                        $p.prev_token.span,
-                        ExprKind::Block(block, None),
-                        AttrVec::new(),
-                    ));
+                    return Ok($p.mk_expr($p.prev_token.span, ExprKind::Block(block, None)));
                 }
                 _ => {}
             };
@@ -120,7 +127,7 @@ impl<'a> Parser<'a> {
                     // Special-case handling of `foo(_, _, _)`
                     err.emit();
                     self.bump();
-                    Ok(self.mk_expr(self.prev_token.span, ExprKind::Err, AttrVec::new()))
+                    Ok(self.mk_expr(self.prev_token.span, ExprKind::Err))
                 }
                 _ => Err(err),
             },
@@ -225,15 +232,18 @@ impl<'a> Parser<'a> {
                     AssocOp::Equal => "==",
                     AssocOp::NotEqual => "!=",
                     _ => unreachable!(),
-                };
-                self.struct_span_err(sp, &format!("invalid comparison operator `{sugg}=`"))
-                    .span_suggestion_short(
-                        sp,
-                        &format!("`{s}=` is not a valid comparison operator, use `{s}`", s = sugg),
-                        sugg,
-                        Applicability::MachineApplicable,
-                    )
-                    .emit();
+                }
+                .into();
+                let invalid = format!("{}=", &sugg);
+                self.sess.emit_err(InvalidComparisonOperator {
+                    span: sp,
+                    invalid: invalid.clone(),
+                    sub: InvalidComparisonOperatorSub::Correctable {
+                        span: sp,
+                        invalid,
+                        correct: sugg,
+                    },
+                });
                 self.bump();
             }
 
@@ -243,14 +253,15 @@ impl<'a> Parser<'a> {
                 && self.prev_token.span.hi() == self.token.span.lo()
             {
                 let sp = op.span.to(self.token.span);
-                self.struct_span_err(sp, "invalid comparison operator `<>`")
-                    .span_suggestion_short(
-                        sp,
-                        "`<>` is not a valid comparison operator, use `!=`",
-                        "!=",
-                        Applicability::MachineApplicable,
-                    )
-                    .emit();
+                self.sess.emit_err(InvalidComparisonOperator {
+                    span: sp,
+                    invalid: "<>".into(),
+                    sub: InvalidComparisonOperatorSub::Correctable {
+                        span: sp,
+                        invalid: "<>".into(),
+                        correct: "!=".into(),
+                    },
+                });
                 self.bump();
             }
 
@@ -260,12 +271,11 @@ impl<'a> Parser<'a> {
                 && self.prev_token.span.hi() == self.token.span.lo()
             {
                 let sp = op.span.to(self.token.span);
-                self.struct_span_err(sp, "invalid comparison operator `<=>`")
-                    .span_label(
-                        sp,
-                        "`<=>` is not a valid comparison operator, use `std::cmp::Ordering`",
-                    )
-                    .emit();
+                self.sess.emit_err(InvalidComparisonOperator {
+                    span: sp,
+                    invalid: "<=>".into(),
+                    sub: InvalidComparisonOperatorSub::Spaceship(sp),
+                });
                 self.bump();
             }
 
@@ -329,11 +339,9 @@ impl<'a> Parser<'a> {
                 | AssocOp::GreaterEqual => {
                     let ast_op = op.to_ast_binop().unwrap();
                     let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
-                    self.mk_expr(span, binary, AttrVec::new())
-                }
-                AssocOp::Assign => {
-                    self.mk_expr(span, ExprKind::Assign(lhs, rhs, cur_op_span), AttrVec::new())
+                    self.mk_expr(span, binary)
                 }
+                AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs, cur_op_span)),
                 AssocOp::AssignOp(k) => {
                     let aop = match k {
                         token::Plus => BinOpKind::Add,
@@ -348,7 +356,7 @@ impl<'a> Parser<'a> {
                         token::Shr => BinOpKind::Shr,
                     };
                     let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
-                    self.mk_expr(span, aopexpr, AttrVec::new())
+                    self.mk_expr(span, aopexpr)
                 }
                 AssocOp::As | AssocOp::Colon | AssocOp::DotDot | AssocOp::DotDotEq => {
                     self.span_bug(span, "AssocOp should have been handled by special case")
@@ -441,11 +449,19 @@ impl<'a> Parser<'a> {
             }
             (Some(op), _) => (op, self.token.span),
             (None, Some((Ident { name: sym::and, span }, false))) => {
-                self.error_bad_logical_op("and", "&&", "conjunction");
+                self.sess.emit_err(InvalidLogicalOperator {
+                    span: self.token.span,
+                    incorrect: "and".into(),
+                    sub: InvalidLogicalOperatorSub::Conjunction(self.token.span),
+                });
                 (AssocOp::LAnd, span)
             }
             (None, Some((Ident { name: sym::or, span }, false))) => {
-                self.error_bad_logical_op("or", "||", "disjunction");
+                self.sess.emit_err(InvalidLogicalOperator {
+                    span: self.token.span,
+                    incorrect: "or".into(),
+                    sub: InvalidLogicalOperatorSub::Disjunction(self.token.span),
+                });
                 (AssocOp::LOr, span)
             }
             _ => return None,
@@ -453,19 +469,6 @@ impl<'a> Parser<'a> {
         Some(source_map::respan(span, op))
     }
 
-    /// Error on `and` and `or` suggesting `&&` and `||` respectively.
-    fn error_bad_logical_op(&self, bad: &str, good: &str, english: &str) {
-        self.struct_span_err(self.token.span, &format!("`{bad}` is not a logical operator"))
-            .span_suggestion_short(
-                self.token.span,
-                &format!("use `{good}` to perform logical {english}"),
-                good,
-                Applicability::MachineApplicable,
-            )
-            .note("unlike in e.g., python and PHP, `&&` and `||` are used for logical operators")
-            .emit();
-    }
-
     /// Checks if this expression is a successfully parsed statement.
     fn expr_is_complete(&self, e: &Expr) -> bool {
         self.restrictions.contains(Restrictions::STMT_EXPR)
@@ -491,7 +494,7 @@ impl<'a> Parser<'a> {
         let limits =
             if op == AssocOp::DotDot { RangeLimits::HalfOpen } else { RangeLimits::Closed };
         let range = self.mk_range(Some(lhs), rhs, limits);
-        Ok(self.mk_expr(span, range, AttrVec::new()))
+        Ok(self.mk_expr(span, range))
     }
 
     fn is_at_start_of_range_notation_rhs(&self) -> bool {
@@ -540,7 +543,7 @@ impl<'a> Parser<'a> {
                 (lo, None)
             };
             let range = this.mk_range(None, opt_end, limits);
-            Ok(this.mk_expr(span, range, attrs.into()))
+            Ok(this.mk_expr_with_attrs(span, range, attrs))
         })
     }
 
@@ -553,7 +556,7 @@ impl<'a> Parser<'a> {
             ($this:ident, $attrs:expr, |this, _| $body:expr) => {
                 $this.collect_tokens_for_expr($attrs, |$this, attrs| {
                     let (hi, ex) = $body?;
-                    Ok($this.mk_expr(lo.to(hi), ex, attrs.into()))
+                    Ok($this.mk_expr_with_attrs(lo.to(hi), ex, attrs))
                 })
             };
         }
@@ -630,14 +633,7 @@ impl<'a> Parser<'a> {
 
     // Recover on `!` suggesting for bitwise negation instead.
     fn recover_tilde_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
-        self.struct_span_err(lo, "`~` cannot be used as a unary operator")
-            .span_suggestion_short(
-                lo,
-                "use `!` to perform bitwise not",
-                "!",
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        self.sess.emit_err(TildeAsUnaryOperator(lo));
 
         self.parse_unary_expr(lo, UnOp::Not)
     }
@@ -663,20 +659,14 @@ impl<'a> Parser<'a> {
     /// Recover on `not expr` in favor of `!expr`.
     fn recover_not_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
         // Emit the error...
-        let not_token = self.look_ahead(1, |t| t.clone());
-        self.struct_span_err(
-            not_token.span,
-            &format!("unexpected {} after identifier", super::token_descr(&not_token)),
-        )
-        .span_suggestion_short(
+        let negated_token = self.look_ahead(1, |t| t.clone());
+        self.sess.emit_err(NotAsNegationOperator {
+            negated: negated_token.span,
+            negated_desc: super::token_descr(&negated_token),
             // Span the `not` plus trailing whitespace to avoid
             // trailing whitespace after the `!` in our suggestion
-            self.sess.source_map().span_until_non_whitespace(lo.to(not_token.span)),
-            "use `!` to perform logical negation",
-            "!",
-            Applicability::MachineApplicable,
-        )
-        .emit();
+            not: self.sess.source_map().span_until_non_whitespace(lo.to(negated_token.span)),
+        });
 
         // ...and recover!
         self.parse_unary_expr(lo, UnOp::Not)
@@ -705,11 +695,7 @@ impl<'a> Parser<'a> {
         expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind,
     ) -> PResult<'a, P<Expr>> {
         let mk_expr = |this: &mut Self, lhs: P<Expr>, rhs: P<Ty>| {
-            this.mk_expr(
-                this.mk_expr_sp(&lhs, lhs_span, rhs.span),
-                expr_kind(lhs, rhs),
-                AttrVec::new(),
-            )
+            this.mk_expr(this.mk_expr_sp(&lhs, lhs_span, rhs.span), expr_kind(lhs, rhs))
         };
 
         // Save the state of the parser before parsing type normally, in case there is a
@@ -737,17 +723,13 @@ impl<'a> Parser<'a> {
                                 segments[0].ident.span,
                             ),
                         };
-                        match self.parse_labeled_expr(label, AttrVec::new(), false) {
+                        match self.parse_labeled_expr(label, false) {
                             Ok(expr) => {
                                 type_err.cancel();
-                                self.struct_span_err(label.ident.span, "malformed loop label")
-                                    .span_suggestion(
-                                        label.ident.span,
-                                        "use the correct loop label format",
-                                        label.ident,
-                                        Applicability::MachineApplicable,
-                                    )
-                                    .emit();
+                                self.sess.emit_err(MalformedLoopLabel {
+                                    span: label.ident.span,
+                                    correct_label: label.ident,
+                                });
                                 return Ok(expr);
                             }
                             Err(err) => {
@@ -859,7 +841,7 @@ impl<'a> Parser<'a> {
             );
             let mut err = self.struct_span_err(span, &msg);
 
-            let suggest_parens = |err: &mut DiagnosticBuilder<'_, _>| {
+            let suggest_parens = |err: &mut Diagnostic| {
                 let suggestions = vec![
                     (span.shrink_to_lo(), "(".to_string()),
                     (span.shrink_to_hi(), ")".to_string()),
@@ -925,15 +907,7 @@ impl<'a> Parser<'a> {
     }
 
     fn error_remove_borrow_lifetime(&self, span: Span, lt_span: Span) {
-        self.struct_span_err(span, "borrow expressions cannot be annotated with lifetimes")
-            .span_label(lt_span, "annotated with lifetime here")
-            .span_suggestion(
-                lt_span,
-                "remove the lifetime annotation",
-                "",
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        self.sess.emit_err(LifetimeInBorrowExpression { span, lifetime_span: lt_span });
     }
 
     /// Parse `mut?` or `raw [ const | mut ]`.
@@ -965,18 +939,23 @@ impl<'a> Parser<'a> {
         &mut self,
         e0: P<Expr>,
         lo: Span,
-        mut attrs: Vec<ast::Attribute>,
+        mut attrs: ast::AttrVec,
     ) -> PResult<'a, P<Expr>> {
         // Stitch the list of outer attributes onto the return value.
         // A little bit ugly, but the best way given the current code
         // structure
-        self.parse_dot_or_call_expr_with_(e0, lo).map(|expr| {
-            expr.map(|mut expr| {
-                attrs.extend::<Vec<_>>(expr.attrs.into());
-                expr.attrs = attrs.into();
-                expr
+        let res = self.parse_dot_or_call_expr_with_(e0, lo);
+        if attrs.is_empty() {
+            res
+        } else {
+            res.map(|expr| {
+                expr.map(|mut expr| {
+                    attrs.extend(expr.attrs);
+                    expr.attrs = attrs;
+                    expr
+                })
             })
-        })
+        }
     }
 
     fn parse_dot_or_call_expr_with_(&mut self, mut e: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
@@ -990,7 +969,7 @@ impl<'a> Parser<'a> {
             };
             if has_question {
                 // `expr?`
-                e = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Try(e), AttrVec::new());
+                e = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Try(e));
                 continue;
             }
             let has_dot = if self.prev_token.kind == TokenKind::Ident(kw::Return, false) {
@@ -1168,7 +1147,7 @@ impl<'a> Parser<'a> {
         let span = self.prev_token.span;
         let field = ExprKind::Field(base, Ident::new(field, span));
         self.expect_no_suffix(span, "a tuple index", suffix);
-        self.mk_expr(lo.to(span), field, AttrVec::new())
+        self.mk_expr(lo.to(span), field)
     }
 
     /// Parse a function call expression, `expr(...)`.
@@ -1182,9 +1161,9 @@ impl<'a> Parser<'a> {
         };
         let open_paren = self.token.span;
 
-        let mut seq = self.parse_paren_expr_seq().map(|args| {
-            self.mk_expr(lo.to(self.prev_token.span), self.mk_call(fun, args), AttrVec::new())
-        });
+        let mut seq = self
+            .parse_paren_expr_seq()
+            .map(|args| self.mk_expr(lo.to(self.prev_token.span), self.mk_call(fun, args)));
         if let Some(expr) =
             self.maybe_recover_struct_lit_bad_delims(lo, open_paren, &mut seq, snapshot)
         {
@@ -1258,10 +1237,13 @@ impl<'a> Parser<'a> {
 
     /// Parse an indexing expression `expr[...]`.
     fn parse_index_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
+        let prev_span = self.prev_token.span;
+        let open_delim_span = self.token.span;
         self.bump(); // `[`
         let index = self.parse_expr()?;
+        self.suggest_missing_semicolon_before_array(prev_span, open_delim_span)?;
         self.expect(&token::CloseDelim(Delimiter::Bracket))?;
-        Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_index(base, index), AttrVec::new()))
+        Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_index(base, index)))
     }
 
     /// Assuming we have just parsed `.`, continue parsing into an expression.
@@ -1282,19 +1264,15 @@ impl<'a> Parser<'a> {
 
             let fn_span = fn_span_lo.to(self.prev_token.span);
             let span = lo.to(self.prev_token.span);
-            Ok(self.mk_expr(span, ExprKind::MethodCall(segment, args, fn_span), AttrVec::new()))
+            Ok(self.mk_expr(span, ExprKind::MethodCall(segment, args, fn_span)))
         } else {
             // Field access `expr.f`
             if let Some(args) = segment.args {
-                self.struct_span_err(
-                    args.span(),
-                    "field expressions cannot have generic arguments",
-                )
-                .emit();
+                self.sess.emit_err(FieldExpressionWithGeneric(args.span()));
             }
 
             let span = lo.to(self.prev_token.span);
-            Ok(self.mk_expr(span, ExprKind::Field(self_arg, segment.ident), AttrVec::new()))
+            Ok(self.mk_expr(span, ExprKind::Field(self_arg, segment.ident)))
         }
     }
 
@@ -1309,10 +1287,6 @@ impl<'a> Parser<'a> {
 
         // Outer attributes are already parsed and will be
         // added to the return value after the fact.
-        //
-        // Therefore, prevent sub-parser from parsing
-        // attributes by giving them an empty "already-parsed" list.
-        let attrs = AttrVec::new();
 
         // Note: when adding new syntax here, don't forget to adjust `TokenKind::can_begin_expr()`.
         let lo = self.token.span;
@@ -1320,13 +1294,13 @@ impl<'a> Parser<'a> {
             // This match arm is a special-case of the `_` match arm below and
             // could be removed without changing functionality, but it's faster
             // to have it here, especially for programs with large constants.
-            self.parse_lit_expr(attrs)
+            self.parse_lit_expr()
         } else if self.check(&token::OpenDelim(Delimiter::Parenthesis)) {
-            self.parse_tuple_parens_expr(attrs)
+            self.parse_tuple_parens_expr()
         } else if self.check(&token::OpenDelim(Delimiter::Brace)) {
-            self.parse_block_expr(None, lo, BlockCheckMode::Default, attrs)
+            self.parse_block_expr(None, lo, BlockCheckMode::Default)
         } else if self.check(&token::BinOp(token::Or)) || self.check(&token::OrOr) {
-            self.parse_closure_expr(attrs).map_err(|mut err| {
+            self.parse_closure_expr().map_err(|mut err| {
                 // If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
                 // then suggest parens around the lhs.
                 if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
@@ -1335,65 +1309,66 @@ impl<'a> Parser<'a> {
                 err
             })
         } else if self.check(&token::OpenDelim(Delimiter::Bracket)) {
-            self.parse_array_or_repeat_expr(attrs, Delimiter::Bracket)
+            self.parse_array_or_repeat_expr(Delimiter::Bracket)
         } else if self.check_path() {
-            self.parse_path_start_expr(attrs)
+            self.parse_path_start_expr()
         } else if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) {
-            self.parse_closure_expr(attrs)
+            self.parse_closure_expr()
         } else if self.eat_keyword(kw::If) {
-            self.parse_if_expr(attrs)
+            self.parse_if_expr()
         } else if self.check_keyword(kw::For) {
             if self.choose_generics_over_qpath(1) {
-                self.parse_closure_expr(attrs)
+                self.parse_closure_expr()
             } else {
                 assert!(self.eat_keyword(kw::For));
-                self.parse_for_expr(None, self.prev_token.span, attrs)
+                self.parse_for_expr(None, self.prev_token.span)
             }
         } else if self.eat_keyword(kw::While) {
-            self.parse_while_expr(None, self.prev_token.span, attrs)
+            self.parse_while_expr(None, self.prev_token.span)
         } else if let Some(label) = self.eat_label() {
-            self.parse_labeled_expr(label, attrs, true)
+            self.parse_labeled_expr(label, true)
         } else if self.eat_keyword(kw::Loop) {
             let sp = self.prev_token.span;
-            self.parse_loop_expr(None, self.prev_token.span, attrs).map_err(|mut err| {
+            self.parse_loop_expr(None, self.prev_token.span).map_err(|mut err| {
                 err.span_label(sp, "while parsing this `loop` expression");
                 err
             })
         } else if self.eat_keyword(kw::Continue) {
             let kind = ExprKind::Continue(self.eat_label());
-            Ok(self.mk_expr(lo.to(self.prev_token.span), kind, attrs))
+            Ok(self.mk_expr(lo.to(self.prev_token.span), kind))
         } else if self.eat_keyword(kw::Match) {
             let match_sp = self.prev_token.span;
-            self.parse_match_expr(attrs).map_err(|mut err| {
+            self.parse_match_expr().map_err(|mut err| {
                 err.span_label(match_sp, "while parsing this `match` expression");
                 err
             })
         } else if self.eat_keyword(kw::Unsafe) {
             let sp = self.prev_token.span;
-            self.parse_block_expr(None, lo, BlockCheckMode::Unsafe(ast::UserProvided), attrs)
-                .map_err(|mut err| {
+            self.parse_block_expr(None, lo, BlockCheckMode::Unsafe(ast::UserProvided)).map_err(
+                |mut err| {
                     err.span_label(sp, "while parsing this `unsafe` expression");
                     err
-                })
+                },
+            )
         } else if self.check_inline_const(0) {
             self.parse_const_block(lo.to(self.token.span), false)
         } else if self.is_do_catch_block() {
-            self.recover_do_catch(attrs)
+            self.recover_do_catch()
         } else if self.is_try_block() {
             self.expect_keyword(kw::Try)?;
-            self.parse_try_block(lo, attrs)
+            self.parse_try_block(lo)
         } else if self.eat_keyword(kw::Return) {
-            self.parse_return_expr(attrs)
+            self.parse_return_expr()
         } else if self.eat_keyword(kw::Break) {
-            self.parse_break_expr(attrs)
+            self.parse_break_expr()
         } else if self.eat_keyword(kw::Yield) {
-            self.parse_yield_expr(attrs)
+            self.parse_yield_expr()
         } else if self.is_do_yeet() {
-            self.parse_yeet_expr(attrs)
+            self.parse_yeet_expr()
         } else if self.check_keyword(kw::Let) {
-            self.parse_let_expr(attrs)
+            self.parse_let_expr()
         } else if self.eat_keyword(kw::Underscore) {
-            Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore, attrs))
+            Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore))
         } else if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
             // Don't complain about bare semicolons after unclosed braces
             // recovery in order to keep the error count down. Fixing the
@@ -1412,32 +1387,32 @@ impl<'a> Parser<'a> {
             if self.check_keyword(kw::Async) {
                 if self.is_async_block() {
                     // Check for `async {` and `async move {`.
-                    self.parse_async_block(attrs)
+                    self.parse_async_block()
                 } else {
-                    self.parse_closure_expr(attrs)
+                    self.parse_closure_expr()
                 }
             } else if self.eat_keyword(kw::Await) {
-                self.recover_incorrect_await_syntax(lo, self.prev_token.span, attrs)
+                self.recover_incorrect_await_syntax(lo, self.prev_token.span)
             } else {
-                self.parse_lit_expr(attrs)
+                self.parse_lit_expr()
             }
         } else {
-            self.parse_lit_expr(attrs)
+            self.parse_lit_expr()
         }
     }
 
-    fn parse_lit_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_lit_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
         match self.parse_opt_lit() {
             Some(literal) => {
-                let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(literal), attrs);
+                let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(literal));
                 self.maybe_recover_from_bad_qpath(expr)
             }
             None => self.try_macro_suggestion(),
         }
     }
 
-    fn parse_tuple_parens_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_tuple_parens_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
         self.expect(&token::OpenDelim(Delimiter::Parenthesis))?;
         let (es, trailing_comma) = match self.parse_seq_to_end(
@@ -1457,15 +1432,11 @@ impl<'a> Parser<'a> {
             // `(e,)` is a tuple with only one field, `e`.
             ExprKind::Tup(es)
         };
-        let expr = self.mk_expr(lo.to(self.prev_token.span), kind, attrs);
+        let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
-    fn parse_array_or_repeat_expr(
-        &mut self,
-        attrs: AttrVec,
-        close_delim: Delimiter,
-    ) -> PResult<'a, P<Expr>> {
+    fn parse_array_or_repeat_expr(&mut self, close_delim: Delimiter) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
         self.bump(); // `[` or other open delim
 
@@ -1494,45 +1465,42 @@ impl<'a> Parser<'a> {
                 ExprKind::Array(vec![first_expr])
             }
         };
-        let expr = self.mk_expr(lo.to(self.prev_token.span), kind, attrs);
+        let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
-    fn parse_path_start_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_path_start_expr(&mut self) -> PResult<'a, P<Expr>> {
         let (qself, path) = if self.eat_lt() {
             let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
             (Some(qself), path)
         } else {
             (None, self.parse_path(PathStyle::Expr)?)
         };
-        let lo = path.span;
 
         // `!`, as an operator, is prefix, so we know this isn't that.
-        let (hi, kind) = if self.eat(&token::Not) {
+        let (span, kind) = if self.eat(&token::Not) {
             // MACRO INVOCATION expression
             if qself.is_some() {
-                self.struct_span_err(path.span, "macros cannot use qualified paths").emit();
+                self.sess.emit_err(MacroInvocationWithQualifiedPath(path.span));
             }
-            let mac = MacCall {
+            let lo = path.span;
+            let mac = P(MacCall {
                 path,
                 args: self.parse_mac_args()?,
                 prior_type_ascription: self.last_type_ascription,
-            };
-            (self.prev_token.span, ExprKind::MacCall(mac))
-        } else if self.check(&token::OpenDelim(Delimiter::Brace)) {
-            if let Some(expr) = self.maybe_parse_struct_expr(qself.as_ref(), &path, &attrs) {
+            });
+            (lo.to(self.prev_token.span), ExprKind::MacCall(mac))
+        } else if self.check(&token::OpenDelim(Delimiter::Brace)) &&
+            let Some(expr) = self.maybe_parse_struct_expr(qself.as_ref(), &path) {
                 if qself.is_some() {
                     self.sess.gated_spans.gate(sym::more_qualified_paths, path.span);
                 }
                 return expr;
-            } else {
-                (path.span, ExprKind::Path(qself, path))
-            }
         } else {
             (path.span, ExprKind::Path(qself, path))
         };
 
-        let expr = self.mk_expr(lo.to(hi), kind, attrs);
+        let expr = self.mk_expr(span, kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
@@ -1540,31 +1508,30 @@ impl<'a> Parser<'a> {
     fn parse_labeled_expr(
         &mut self,
         label: Label,
-        attrs: AttrVec,
         mut consume_colon: bool,
     ) -> PResult<'a, P<Expr>> {
         let lo = label.ident.span;
         let label = Some(label);
         let ate_colon = self.eat(&token::Colon);
         let expr = if self.eat_keyword(kw::While) {
-            self.parse_while_expr(label, lo, attrs)
+            self.parse_while_expr(label, lo)
         } else if self.eat_keyword(kw::For) {
-            self.parse_for_expr(label, lo, attrs)
+            self.parse_for_expr(label, lo)
         } else if self.eat_keyword(kw::Loop) {
-            self.parse_loop_expr(label, lo, attrs)
+            self.parse_loop_expr(label, lo)
         } else if self.check_noexpect(&token::OpenDelim(Delimiter::Brace))
             || self.token.is_whole_block()
         {
-            self.parse_block_expr(label, lo, BlockCheckMode::Default, attrs)
+            self.parse_block_expr(label, lo, BlockCheckMode::Default)
         } else if !ate_colon
             && (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt))
         {
             // We're probably inside of a `Path<'a>` that needs a turbofish
-            let msg = "expected `while`, `for`, `loop` or `{` after a label";
-            self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();
+            self.sess.emit_err(UnexpectedTokenAfterLabel(self.token.span));
             consume_colon = false;
             Ok(self.mk_expr_err(lo))
         } else {
+            // FIXME: use UnexpectedTokenAfterLabel, needs multipart suggestions
             let msg = "expected `while`, `for`, `loop` or `{` after a label";
 
             let mut err = self.struct_span_err(self.token.span, msg);
@@ -1618,10 +1585,10 @@ impl<'a> Parser<'a> {
                     Applicability::MachineApplicable,
                 );
 
-                // Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to supress future errors about `break 'label`.
+                // Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to suppress future errors about `break 'label`.
                 let stmt = self.mk_stmt(span, StmtKind::Expr(expr));
                 let blk = self.mk_block(vec![stmt], BlockCheckMode::Default, span);
-                self.mk_expr(span, ExprKind::Block(blk, label), ThinVec::new())
+                self.mk_expr(span, ExprKind::Block(blk, label))
             });
 
             err.emit();
@@ -1629,44 +1596,27 @@ impl<'a> Parser<'a> {
         }?;
 
         if !ate_colon && consume_colon {
-            self.error_labeled_expr_must_be_followed_by_colon(lo, expr.span);
+            self.sess.emit_err(RequireColonAfterLabeledExpression {
+                span: expr.span,
+                label: lo,
+                label_end: lo.shrink_to_hi(),
+            });
         }
 
         Ok(expr)
     }
 
-    fn error_labeled_expr_must_be_followed_by_colon(&self, lo: Span, span: Span) {
-        self.struct_span_err(span, "labeled expression must be followed by `:`")
-            .span_label(lo, "the label")
-            .span_suggestion_short(
-                lo.shrink_to_hi(),
-                "add `:` after the label",
-                ": ",
-                Applicability::MachineApplicable,
-            )
-            .note("labels are used before loops and blocks, allowing e.g., `break 'label` to them")
-            .emit();
-    }
-
     /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
-    fn recover_do_catch(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn recover_do_catch(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
 
         self.bump(); // `do`
         self.bump(); // `catch`
 
-        let span_dc = lo.to(self.prev_token.span);
-        self.struct_span_err(span_dc, "found removed `do catch` syntax")
-            .span_suggestion(
-                span_dc,
-                "replace with the new syntax",
-                "try",
-                Applicability::MachineApplicable,
-            )
-            .note("following RFC #2388, the new non-placeholder syntax is `try`")
-            .emit();
+        let span = lo.to(self.prev_token.span);
+        self.sess.emit_err(DoCatchSyntaxRemoved { span });
 
-        self.parse_try_block(lo, attrs)
+        self.parse_try_block(lo)
     }
 
     /// Parse an expression if the token can begin one.
@@ -1675,15 +1625,15 @@ impl<'a> Parser<'a> {
     }
 
     /// Parse `"return" expr?`.
-    fn parse_return_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_return_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
         let kind = ExprKind::Ret(self.parse_expr_opt()?);
-        let expr = self.mk_expr(lo.to(self.prev_token.span), kind, attrs);
+        let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
     /// Parse `"do" "yeet" expr?`.
-    fn parse_yeet_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_yeet_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
 
         self.bump(); // `do`
@@ -1693,7 +1643,7 @@ impl<'a> Parser<'a> {
 
         let span = lo.to(self.prev_token.span);
         self.sess.gated_spans.gate(sym::yeet_expr, span);
-        let expr = self.mk_expr(span, kind, attrs);
+        let expr = self.mk_expr(span, kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
@@ -1705,13 +1655,13 @@ impl<'a> Parser<'a> {
     /// `break 'lbl: loop {}`); a labeled break with an unlabeled loop as its value
     /// expression only gets a warning for compatibility reasons; and a labeled break
     /// with a labeled loop does not even get a warning because there is no ambiguity.
-    fn parse_break_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_break_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
         let mut label = self.eat_label();
         let kind = if label.is_some() && self.token == token::Colon {
             // The value expression can be a labeled loop, see issue #86948, e.g.:
             // `loop { break 'label: loop { break 'label 42; }; }`
-            let lexpr = self.parse_labeled_expr(label.take().unwrap(), AttrVec::new(), true)?;
+            let lexpr = self.parse_labeled_expr(label.take().unwrap(), true)?;
             self.struct_span_err(
                 lexpr.span,
                 "parentheses are required around this expression to avoid confusion with a labeled break expression",
@@ -1753,17 +1703,17 @@ impl<'a> Parser<'a> {
         } else {
             None
         };
-        let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Break(label, kind), attrs);
+        let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Break(label, kind));
         self.maybe_recover_from_bad_qpath(expr)
     }
 
     /// Parse `"yield" expr?`.
-    fn parse_yield_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_yield_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
         let kind = ExprKind::Yield(self.parse_expr_opt()?);
         let span = lo.to(self.prev_token.span);
         self.sess.gated_spans.gate(sym::generators, span);
-        let expr = self.mk_expr(span, kind, attrs);
+        let expr = self.mk_expr(span, kind);
         self.maybe_recover_from_bad_qpath(expr)
     }
 
@@ -1775,8 +1725,8 @@ impl<'a> Parser<'a> {
             Some(lit) => match lit.kind {
                 ast::LitKind::Str(symbol_unescaped, style) => Ok(ast::StrLit {
                     style,
-                    symbol: lit.token.symbol,
-                    suffix: lit.token.suffix,
+                    symbol: lit.token_lit.symbol,
+                    suffix: lit.token_lit.suffix,
                     span: lit.span,
                     symbol_unescaped,
                 }),
@@ -1853,20 +1803,16 @@ impl<'a> Parser<'a> {
                 let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None);
                 let symbol = Symbol::intern(&suffixless_lit.to_string());
                 let lit = token::Lit::new(token::Err, symbol, lit.suffix);
-                Some(Lit::from_lit_token(lit, span).unwrap_or_else(|_| unreachable!()))
+                Some(Lit::from_token_lit(lit, span).unwrap_or_else(|_| unreachable!()))
             }
         }
     }
 
     fn error_float_lits_must_have_int_part(&self, token: &Token) {
-        self.struct_span_err(token.span, "float literals must have an integer part")
-            .span_suggestion(
-                token.span,
-                "must have an integer part",
-                pprust::token_to_string(token),
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        self.sess.emit_err(FloatLiteralRequiresIntegerPart {
+            span: token.span,
+            correct: pprust::token_to_string(token).into_owned(),
+        });
     }
 
     fn report_lit_error(&self, err: LitError, lit: token::Lit, span: Span) {
@@ -1908,28 +1854,11 @@ impl<'a> Parser<'a> {
                 let suf = suf.as_str();
                 if looks_like_width_suffix(&['i', 'u'], &suf) {
                     // If it looks like a width, try to be helpful.
-                    let msg = format!("invalid width `{}` for integer literal", &suf[1..]);
-                    self.struct_span_err(span, &msg)
-                        .help("valid widths are 8, 16, 32, 64 and 128")
-                        .emit();
+                    self.sess.emit_err(InvalidIntLiteralWidth { span, width: suf[1..].into() });
                 } else if let Some(fixed) = fix_base_capitalisation(suf) {
-                    let msg = "invalid base prefix for number literal";
-
-                    self.struct_span_err(span, msg)
-                        .note("base prefixes (`0xff`, `0b1010`, `0o755`) are lowercase")
-                        .span_suggestion(
-                            span,
-                            "try making the prefix lowercase",
-                            fixed,
-                            Applicability::MaybeIncorrect,
-                        )
-                        .emit();
+                    self.sess.emit_err(InvalidNumLiteralBasePrefix { span, fixed });
                 } else {
-                    let msg = format!("invalid suffix `{suf}` for number literal");
-                    self.struct_span_err(span, &msg)
-                        .span_label(span, format!("invalid suffix `{suf}`"))
-                        .help("the suffix must be one of the numeric types (`u32`, `isize`, `f32`, etc.)")
-                        .emit();
+                    self.sess.emit_err(InvalidNumLiteralSuffix { span, suffix: suf.to_string() });
                 }
             }
             LitError::InvalidFloatSuffix => {
@@ -1937,14 +1866,10 @@ impl<'a> Parser<'a> {
                 let suf = suf.as_str();
                 if looks_like_width_suffix(&['f'], suf) {
                     // If it looks like a width, try to be helpful.
-                    let msg = format!("invalid width `{}` for float literal", &suf[1..]);
-                    self.struct_span_err(span, &msg).help("valid widths are 32 and 64").emit();
+                    self.sess
+                        .emit_err(InvalidFloatLiteralWidth { span, width: suf[1..].to_string() });
                 } else {
-                    let msg = format!("invalid suffix `{suf}` for float literal");
-                    self.struct_span_err(span, &msg)
-                        .span_label(span, format!("invalid suffix `{suf}`"))
-                        .help("valid suffixes are `f32` and `f64`")
-                        .emit();
+                    self.sess.emit_err(InvalidFloatLiteralSuffix { span, suffix: suf.to_string() });
                 }
             }
             LitError::NonDecimalFloat(base) => {
@@ -1959,7 +1884,7 @@ impl<'a> Parser<'a> {
                     .emit();
             }
             LitError::IntTooLarge => {
-                self.struct_span_err(span, "integer literal is too large").emit();
+                self.sess.emit_err(IntLiteralTooLarge { span });
             }
         }
     }
@@ -2007,14 +1932,10 @@ impl<'a> Parser<'a> {
         let lo = self.token.span;
         let minus_present = self.eat(&token::BinOp(token::Minus));
         let lit = self.parse_lit()?;
-        let expr = self.mk_expr(lit.span, ExprKind::Lit(lit), AttrVec::new());
+        let expr = self.mk_expr(lit.span, ExprKind::Lit(lit));
 
         if minus_present {
-            Ok(self.mk_expr(
-                lo.to(self.prev_token.span),
-                self.mk_unary(UnOp::Neg, expr),
-                AttrVec::new(),
-            ))
+            Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_unary(UnOp::Neg, expr)))
         } else {
             Ok(expr)
         }
@@ -2029,13 +1950,9 @@ impl<'a> Parser<'a> {
     /// Emits a suggestion if it looks like the user meant an array but
     /// accidentally used braces, causing the code to be interpreted as a block
     /// expression.
-    fn maybe_suggest_brackets_instead_of_braces(
-        &mut self,
-        lo: Span,
-        attrs: AttrVec,
-    ) -> Option<P<Expr>> {
+    fn maybe_suggest_brackets_instead_of_braces(&mut self, lo: Span) -> Option<P<Expr>> {
         let mut snapshot = self.create_snapshot_for_diagnostic();
-        match snapshot.parse_array_or_repeat_expr(attrs, Delimiter::Brace) {
+        match snapshot.parse_array_or_repeat_expr(Delimiter::Brace) {
             Ok(arr) => {
                 let hi = snapshot.prev_token.span;
                 self.struct_span_err(arr.span, "this is a block expression, not an array")
@@ -2056,43 +1973,76 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn suggest_missing_semicolon_before_array(
+        &self,
+        prev_span: Span,
+        open_delim_span: Span,
+    ) -> PResult<'a, ()> {
+        if self.token.kind == token::Comma {
+            if !self.sess.source_map().is_multiline(prev_span.until(self.token.span)) {
+                return Ok(());
+            }
+            let mut snapshot = self.create_snapshot_for_diagnostic();
+            snapshot.bump();
+            match snapshot.parse_seq_to_before_end(
+                &token::CloseDelim(Delimiter::Bracket),
+                SeqSep::trailing_allowed(token::Comma),
+                |p| p.parse_expr(),
+            ) {
+                Ok(_)
+                    // When the close delim is `)`, `token.kind` is expected to be `token::CloseDelim(Delimiter::Parenthesis)`,
+                    // but the actual `token.kind` is `token::CloseDelim(Delimiter::Bracket)`.
+                    // This is because the `token.kind` of the close delim is treated as the same as
+                    // that of the open delim in `TokenTreesReader::parse_token_tree`, even if the delimiters of them are different.
+                    // Therefore, `token.kind` should not be compared here.
+                    if snapshot
+                        .span_to_snippet(snapshot.token.span)
+                        .map_or(false, |snippet| snippet == "]") =>
+                {
+                    return Err(MissingSemicolonBeforeArray {
+                        open_delim: open_delim_span,
+                        semicolon: prev_span.shrink_to_hi(),
+                    }.into_diagnostic(&self.sess.span_diagnostic));
+                }
+                Ok(_) => (),
+                Err(err) => err.cancel(),
+            }
+        }
+        Ok(())
+    }
+
     /// Parses a block or unsafe block.
     pub(super) fn parse_block_expr(
         &mut self,
         opt_label: Option<Label>,
         lo: Span,
         blk_mode: BlockCheckMode,
-        mut attrs: AttrVec,
     ) -> PResult<'a, P<Expr>> {
         if self.is_array_like_block() {
-            if let Some(arr) = self.maybe_suggest_brackets_instead_of_braces(lo, attrs.clone()) {
+            if let Some(arr) = self.maybe_suggest_brackets_instead_of_braces(lo) {
                 return Ok(arr);
             }
         }
 
-        if let Some(label) = opt_label {
-            self.sess.gated_spans.gate(sym::label_break_value, label.ident.span);
-        }
-
         if self.token.is_whole_block() {
-            self.struct_span_err(self.token.span, "cannot use a `block` macro fragment here")
-                .span_label(lo.to(self.token.span), "the `block` fragment is within this context")
-                .emit();
+            self.sess.emit_err(InvalidBlockMacroSegment {
+                span: self.token.span,
+                context: lo.to(self.token.span),
+            });
         }
 
-        let (inner_attrs, blk) = self.parse_block_common(lo, blk_mode)?;
-        attrs.extend(inner_attrs);
-        Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs))
+        let (attrs, blk) = self.parse_block_common(lo, blk_mode)?;
+        Ok(self.mk_expr_with_attrs(blk.span, ExprKind::Block(blk, opt_label), attrs))
     }
 
     /// Parse a block which takes no attributes and has no label
     fn parse_simple_block(&mut self) -> PResult<'a, P<Expr>> {
         let blk = self.parse_block()?;
-        Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()))
+        Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None)))
     }
 
     /// Parses a closure expression (e.g., `move |args| expr`).
-    fn parse_closure_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_closure_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
 
         let binder = if self.check_keyword(kw::For) {
@@ -2127,7 +2077,7 @@ impl<'a> Parser<'a> {
             _ => {
                 // If an explicit return type is given, require a block to appear (RFC 968).
                 let body_lo = self.token.span;
-                self.parse_block_expr(None, body_lo, BlockCheckMode::Default, AttrVec::new())?
+                self.parse_block_expr(None, body_lo, BlockCheckMode::Default)?
             }
         };
 
@@ -2158,7 +2108,6 @@ impl<'a> Parser<'a> {
                 body,
                 lo.to(decl_hi),
             ),
-            attrs,
         );
 
         // Disable recovery for closure body
@@ -2221,10 +2170,10 @@ impl<'a> Parser<'a> {
 
             Ok((
                 Param {
-                    attrs: attrs.into(),
+                    attrs,
                     ty,
                     pat,
-                    span: lo.to(this.token.span),
+                    span: lo.to(this.prev_token.span),
                     id: DUMMY_NODE_ID,
                     is_placeholder: false,
                 },
@@ -2234,19 +2183,13 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses an `if` expression (`if` token already eaten).
-    fn parse_if_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_if_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
         let cond = self.parse_cond_expr()?;
-
-        self.parse_if_after_cond(attrs, lo, cond)
+        self.parse_if_after_cond(lo, cond)
     }
 
-    fn parse_if_after_cond(
-        &mut self,
-        attrs: AttrVec,
-        lo: Span,
-        mut cond: P<Expr>,
-    ) -> PResult<'a, P<Expr>> {
+    fn parse_if_after_cond(&mut self, lo: Span, mut cond: P<Expr>) -> PResult<'a, P<Expr>> {
         let cond_span = cond.span;
         // Tries to interpret `cond` as either a missing expression if it's a block,
         // or as an unfinished expression if it's a binop and the RHS is a block.
@@ -2255,11 +2198,19 @@ impl<'a> Parser<'a> {
             let block = match &mut cond.kind {
                 ExprKind::Binary(Spanned { span: binop_span, .. }, _, right)
                     if let ExprKind::Block(_, None) = right.kind => {
-                        this.error_missing_if_then_block(lo, cond_span.shrink_to_lo().to(*binop_span), true).emit();
+                        self.sess.emit_err(IfExpressionMissingThenBlock {
+                            if_span: lo,
+                            sub: IfExpressionMissingThenBlockSub::UnfinishedCondition(
+                                cond_span.shrink_to_lo().to(*binop_span)
+                            ),
+                        });
                         std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi()))
                     },
                 ExprKind::Block(_, None) => {
-                    this.error_missing_if_cond(lo, cond_span).emit();
+                    self.sess.emit_err(IfExpressionMissingCondition {
+                        if_span: self.sess.source_map().next_point(lo),
+                        block_span: self.sess.source_map().start_point(cond_span),
+                    });
                     std::mem::replace(&mut cond, this.mk_expr_err(cond_span.shrink_to_hi()))
                 }
                 _ => {
@@ -2277,7 +2228,10 @@ impl<'a> Parser<'a> {
             if let Some(block) = recover_block_from_condition(self) {
                 block
             } else {
-                self.error_missing_if_then_block(lo, cond_span, false).emit();
+                self.sess.emit_err(IfExpressionMissingThenBlock {
+                    if_span: lo,
+                    sub: IfExpressionMissingThenBlockSub::AddThenBlock(cond_span.shrink_to_hi()),
+                });
                 self.mk_block_err(cond_span.shrink_to_hi())
             }
         } else {
@@ -2302,45 +2256,13 @@ impl<'a> Parser<'a> {
             block
         };
         let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None };
-        Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els), attrs))
-    }
-
-    fn error_missing_if_then_block(
-        &self,
-        if_span: Span,
-        cond_span: Span,
-        is_unfinished: bool,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        let mut err = self.struct_span_err(
-            if_span,
-            "this `if` expression is missing a block after the condition",
-        );
-        if is_unfinished {
-            err.span_help(cond_span, "this binary operation is possibly unfinished");
-        } else {
-            err.span_help(cond_span.shrink_to_hi(), "add a block here");
-        }
-        err
-    }
-
-    fn error_missing_if_cond(
-        &self,
-        lo: Span,
-        span: Span,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
-        let next_span = self.sess.source_map().next_point(lo);
-        let mut err = self.struct_span_err(next_span, "missing condition for `if` expression");
-        err.span_label(next_span, "expected condition here");
-        err.span_label(
-            self.sess.source_map().start_point(span),
-            "if this block is the condition of the `if` expression, then it must be followed by another block"
-        );
-        err
+        Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els)))
     }
 
     /// Parses the condition of a `if` or `while` expression.
     fn parse_cond_expr(&mut self) -> PResult<'a, P<Expr>> {
-        let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)?;
+        let cond =
+            self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)?;
 
         if let ExprKind::Let(..) = cond.kind {
             // Remove the last feature gating of a `let` expression since it's stable.
@@ -2351,7 +2273,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a `let $pat = $expr` pseudo-expression.
-    fn parse_let_expr(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_let_expr(&mut self) -> PResult<'a, P<Expr>> {
         // This is a *approximate* heuristic that detects if `let` chains are
         // being parsed in the right position. It's approximate because it
         // doesn't deny all invalid `let` expressions, just completely wrong usages.
@@ -2360,8 +2282,7 @@ impl<'a> Parser<'a> {
             TokenKind::AndAnd | TokenKind::Ident(kw::If, _) | TokenKind::Ident(kw::While, _)
         );
         if !self.restrictions.contains(Restrictions::ALLOW_LET) || not_in_chain {
-            self.struct_span_err(self.token.span, "expected expression, found `let` statement")
-                .emit();
+            self.sess.emit_err(ExpectedExpressionFoundLet { span: self.token.span });
         }
 
         self.bump(); // Eat `let` token
@@ -2378,7 +2299,7 @@ impl<'a> Parser<'a> {
         })?;
         let span = lo.to(expr.span);
         self.sess.gated_spans.gate(sym::let_chains, span);
-        Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span), attrs))
+        Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span)))
     }
 
     /// Parses an `else { ... }` expression (`else` token already eaten).
@@ -2386,7 +2307,7 @@ impl<'a> Parser<'a> {
         let else_span = self.prev_token.span; // `else`
         let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
         let expr = if self.eat_keyword(kw::If) {
-            self.parse_if_expr(AttrVec::new())?
+            self.parse_if_expr()?
         } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
             self.parse_simple_block()?
         } else {
@@ -2400,16 +2321,13 @@ impl<'a> Parser<'a> {
                     if self.check(&TokenKind::OpenDelim(Delimiter::Brace))
                         && classify::expr_requires_semi_to_be_stmt(&cond) =>
                 {
-                    self.struct_span_err(first_tok_span, format!("expected `{{`, found {first_tok}"))
-                        .span_label(else_span, "expected an `if` or a block after this `else`")
-                        .span_suggestion(
-                            cond.span.shrink_to_lo(),
-                            "add an `if` if this is the condition of a chained `else if` statement",
-                            "if ",
-                            Applicability::MaybeIncorrect,
-                        )
-                        .emit();
-                    self.parse_if_after_cond(AttrVec::new(), cond.span.shrink_to_lo(), cond)?
+                    self.sess.emit_err(ExpectedElseBlock {
+                        first_tok_span,
+                        first_tok,
+                        else_span,
+                        condition_start: cond.span.shrink_to_lo(),
+                    });
+                    self.parse_if_after_cond(cond.span.shrink_to_lo(), cond)?
                 }
                 Err(e) => {
                     e.cancel();
@@ -2433,25 +2351,22 @@ impl<'a> Parser<'a> {
         branch_span: Span,
         attrs: &[ast::Attribute],
     ) {
-        let (span, last) = match attrs {
+        let (attributes, last) = match attrs {
             [] => return,
             [x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
         };
         let ctx = if is_ctx_else { "else" } else { "if" };
-        self.struct_span_err(last, "outer attributes are not allowed on `if` and `else` branches")
-            .span_label(branch_span, "the attributes are attached to this branch")
-            .span_label(ctx_span, format!("the branch belongs to this `{ctx}`"))
-            .span_suggestion(span, "remove the attributes", "", Applicability::MachineApplicable)
-            .emit();
+        self.sess.emit_err(OuterAttributeNotAllowedOnIfElse {
+            last,
+            branch_span,
+            ctx_span,
+            ctx: ctx.to_string(),
+            attributes,
+        });
     }
 
     /// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
-    fn parse_for_expr(
-        &mut self,
-        opt_label: Option<Label>,
-        lo: Span,
-        mut attrs: AttrVec,
-    ) -> PResult<'a, P<Expr>> {
+    fn parse_for_expr(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
         // Record whether we are about to parse `for (`.
         // This is used below for recovery in case of `for ( $stuff ) $block`
         // in which case we will suggest `for $stuff $block`.
@@ -2474,63 +2389,51 @@ impl<'a> Parser<'a> {
 
         let pat = self.recover_parens_around_for_head(pat, begin_paren);
 
-        let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
-        attrs.extend(iattrs);
+        let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
 
         let kind = ExprKind::ForLoop(pat, expr, loop_block, opt_label);
-        Ok(self.mk_expr(lo.to(self.prev_token.span), kind, attrs))
+        Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
     }
 
     fn error_missing_in_for_loop(&mut self) {
-        let (span, msg, sugg) = if self.token.is_ident_named(sym::of) {
+        let (span, sub): (_, fn(_) -> _) = if self.token.is_ident_named(sym::of) {
             // Possibly using JS syntax (#75311).
             let span = self.token.span;
             self.bump();
-            (span, "try using `in` here instead", "in")
+            (span, MissingInInForLoopSub::InNotOf)
         } else {
-            (self.prev_token.span.between(self.token.span), "try adding `in` here", " in ")
+            (self.prev_token.span.between(self.token.span), MissingInInForLoopSub::AddIn)
         };
-        self.struct_span_err(span, "missing `in` in `for` loop")
-            .span_suggestion_short(
-                span,
-                msg,
-                sugg,
-                // Has been misleading, at least in the past (closed Issue #48492).
-                Applicability::MaybeIncorrect,
-            )
-            .emit();
+
+        self.sess.emit_err(MissingInInForLoop { span, sub: sub(span) });
     }
 
     /// Parses a `while` or `while let` expression (`while` token already eaten).
-    fn parse_while_expr(
-        &mut self,
-        opt_label: Option<Label>,
-        lo: Span,
-        mut attrs: AttrVec,
-    ) -> PResult<'a, P<Expr>> {
+    fn parse_while_expr(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
         let cond = self.parse_cond_expr().map_err(|mut err| {
             err.span_label(lo, "while parsing the condition of this `while` expression");
             err
         })?;
-        let (iattrs, body) = self.parse_inner_attrs_and_block().map_err(|mut err| {
+        let (attrs, body) = self.parse_inner_attrs_and_block().map_err(|mut err| {
             err.span_label(lo, "while parsing the body of this `while` expression");
             err.span_label(cond.span, "this `while` condition successfully parsed");
             err
         })?;
-        attrs.extend(iattrs);
-        Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::While(cond, body, opt_label), attrs))
+        Ok(self.mk_expr_with_attrs(
+            lo.to(self.prev_token.span),
+            ExprKind::While(cond, body, opt_label),
+            attrs,
+        ))
     }
 
     /// Parses `loop { ... }` (`loop` token already eaten).
-    fn parse_loop_expr(
-        &mut self,
-        opt_label: Option<Label>,
-        lo: Span,
-        mut attrs: AttrVec,
-    ) -> PResult<'a, P<Expr>> {
-        let (iattrs, body) = self.parse_inner_attrs_and_block()?;
-        attrs.extend(iattrs);
-        Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::Loop(body, opt_label), attrs))
+    fn parse_loop_expr(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
+        let (attrs, body) = self.parse_inner_attrs_and_block()?;
+        Ok(self.mk_expr_with_attrs(
+            lo.to(self.prev_token.span),
+            ExprKind::Loop(body, opt_label),
+            attrs,
+        ))
     }
 
     pub(crate) fn eat_label(&mut self) -> Option<Label> {
@@ -2541,7 +2444,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a `match ... { ... }` expression (`match` token already eaten).
-    fn parse_match_expr(&mut self, mut attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_match_expr(&mut self) -> PResult<'a, P<Expr>> {
         let match_span = self.prev_token.span;
         let lo = self.prev_token.span;
         let scrutinee = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
@@ -2561,7 +2464,7 @@ impl<'a> Parser<'a> {
                 return Err(e);
             }
         }
-        attrs.extend(self.parse_inner_attributes()?);
+        let attrs = self.parse_inner_attributes()?;
 
         let mut arms: Vec<Arm> = Vec::new();
         while self.token != token::CloseDelim(Delimiter::Brace) {
@@ -2575,13 +2478,17 @@ impl<'a> Parser<'a> {
                     if self.token == token::CloseDelim(Delimiter::Brace) {
                         self.bump();
                     }
-                    return Ok(self.mk_expr(span, ExprKind::Match(scrutinee, arms), attrs));
+                    return Ok(self.mk_expr_with_attrs(
+                        span,
+                        ExprKind::Match(scrutinee, arms),
+                        attrs,
+                    ));
                 }
             }
         }
         let hi = self.token.span;
         self.bump();
-        Ok(self.mk_expr(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
+        Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
     }
 
     /// Attempt to recover from match arm body with statements and no surrounding braces.
@@ -2681,7 +2588,7 @@ impl<'a> Parser<'a> {
     }
 
     pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
-        // Used to check the `let_chains` and `if_let_guard` features mostly by scaning
+        // Used to check the `let_chains` and `if_let_guard` features mostly by scanning
         // `&&` tokens.
         fn check_let_expr(expr: &Expr) -> (bool, bool) {
             match expr.kind {
@@ -2756,7 +2663,7 @@ impl<'a> Parser<'a> {
                     let span = body.span;
                     return Ok((
                         ast::Arm {
-                            attrs: attrs.into(),
+                            attrs,
                             pat,
                             guard,
                             body,
@@ -2811,17 +2718,9 @@ impl<'a> Parser<'a> {
                                 .is_ok();
                             if pattern_follows && snapshot.check(&TokenKind::FatArrow) {
                                 err.cancel();
-                                this.struct_span_err(
-                                    hi.shrink_to_hi(),
-                                    "expected `,` following `match` arm",
-                                )
-                                .span_suggestion(
-                                    hi.shrink_to_hi(),
-                                    "missing a comma here to end this `match` arm",
-                                    ",",
-                                    Applicability::MachineApplicable,
-                                )
-                                .emit();
+                                this.sess.emit_err(MissingCommaAfterMatchArm {
+                                    span: hi.shrink_to_hi(),
+                                });
                                 return Ok(true);
                             }
                         }
@@ -2834,7 +2733,7 @@ impl<'a> Parser<'a> {
 
             Ok((
                 ast::Arm {
-                    attrs: attrs.into(),
+                    attrs,
                     pat,
                     guard,
                     body: expr,
@@ -2848,21 +2747,15 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a `try {...}` expression (`try` token already eaten).
-    fn parse_try_block(&mut self, span_lo: Span, mut attrs: AttrVec) -> PResult<'a, P<Expr>> {
-        let (iattrs, body) = self.parse_inner_attrs_and_block()?;
-        attrs.extend(iattrs);
+    fn parse_try_block(&mut self, span_lo: Span) -> PResult<'a, P<Expr>> {
+        let (attrs, body) = self.parse_inner_attrs_and_block()?;
         if self.eat_keyword(kw::Catch) {
-            let mut error = self.struct_span_err(
-                self.prev_token.span,
-                "keyword `catch` cannot follow a `try` block",
-            );
-            error.help("try using `match` on the result of the `try` block instead");
-            error.emit();
-            Err(error)
+            Err(CatchAfterTry { span: self.prev_token.span }
+                .into_diagnostic(&self.sess.span_diagnostic))
         } else {
             let span = span_lo.to(body.span);
             self.sess.gated_spans.gate(sym::try_blocks, span);
-            Ok(self.mk_expr(span, ExprKind::TryBlock(body), attrs))
+            Ok(self.mk_expr_with_attrs(span, ExprKind::TryBlock(body), attrs))
         }
     }
 
@@ -2884,14 +2777,13 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses an `async move? {...}` expression.
-    fn parse_async_block(&mut self, mut attrs: AttrVec) -> PResult<'a, P<Expr>> {
+    fn parse_async_block(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
         self.expect_keyword(kw::Async)?;
         let capture_clause = self.parse_capture_clause()?;
-        let (iattrs, body) = self.parse_inner_attrs_and_block()?;
-        attrs.extend(iattrs);
+        let (attrs, body) = self.parse_inner_attrs_and_block()?;
         let kind = ExprKind::Async(capture_clause, DUMMY_NODE_ID, body);
-        Ok(self.mk_expr(lo.to(self.prev_token.span), kind, attrs))
+        Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
     }
 
     fn is_async_block(&self) -> bool {
@@ -2925,14 +2817,13 @@ impl<'a> Parser<'a> {
         &mut self,
         qself: Option<&ast::QSelf>,
         path: &ast::Path,
-        attrs: &AttrVec,
     ) -> Option<PResult<'a, P<Expr>>> {
         let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
         if struct_allowed || self.is_certainly_not_a_block() {
             if let Err(err) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
                 return Some(Err(err));
             }
-            let expr = self.parse_struct_expr(qself.cloned(), path.clone(), attrs.clone(), true);
+            let expr = self.parse_struct_expr(qself.cloned(), path.clone(), true);
             if let (Ok(expr), false) = (&expr, struct_allowed) {
                 // This is a struct literal, but we don't can't accept them here.
                 self.error_struct_lit_not_allowed_here(path.span, expr.span);
@@ -3069,7 +2960,6 @@ impl<'a> Parser<'a> {
         &mut self,
         qself: Option<ast::QSelf>,
         pth: ast::Path,
-        attrs: AttrVec,
         recover: bool,
     ) -> PResult<'a, P<Expr>> {
         let lo = pth.span;
@@ -3082,7 +2972,7 @@ impl<'a> Parser<'a> {
         } else {
             ExprKind::Struct(P(ast::StructExpr { qself, path: pth, fields, rest: base }))
         };
-        Ok(self.mk_expr(span, expr, attrs))
+        Ok(self.mk_expr(span, expr))
     }
 
     /// Use in case of error after field-looking code: `S { foo: () with a }`.
@@ -3110,18 +3000,10 @@ impl<'a> Parser<'a> {
         if self.token != token::Comma {
             return;
         }
-        self.struct_span_err(
-            span.to(self.prev_token.span),
-            "cannot use a comma after the base struct",
-        )
-        .span_suggestion_short(
-            self.token.span,
-            "remove this comma",
-            "",
-            Applicability::MachineApplicable,
-        )
-        .note("the base struct must always be the last field")
-        .emit();
+        self.sess.emit_err(CommaAfterBaseStruct {
+            span: span.to(self.prev_token.span),
+            comma: self.token.span,
+        });
         self.recover_stmt();
     }
 
@@ -3137,7 +3019,7 @@ impl<'a> Parser<'a> {
                 // Mimic `x: x` for the `x` field shorthand.
                 let ident = this.parse_ident_common(false)?;
                 let path = ast::Path::from_ident(ident);
-                (ident, this.mk_expr(ident.span, ExprKind::Path(None, path), AttrVec::new()))
+                (ident, this.mk_expr(ident.span, ExprKind::Path(None, path)))
             } else {
                 let ident = this.parse_field_name()?;
                 this.error_on_eq_field_init(ident);
@@ -3151,7 +3033,7 @@ impl<'a> Parser<'a> {
                     span: lo.to(expr.span),
                     expr,
                     is_shorthand,
-                    attrs: attrs.into(),
+                    attrs,
                     id: DUMMY_NODE_ID,
                     is_placeholder: false,
                 },
@@ -3167,43 +3049,18 @@ impl<'a> Parser<'a> {
             return;
         }
 
-        self.struct_span_err(self.token.span, "expected `:`, found `=`")
-            .span_suggestion(
-                field_name.span.shrink_to_hi().to(self.token.span),
-                "replace equals symbol with a colon",
-                ":",
-                Applicability::MachineApplicable,
-            )
-            .emit();
+        self.sess.emit_err(EqFieldInit {
+            span: self.token.span,
+            eq: field_name.span.shrink_to_hi().to(self.token.span),
+        });
     }
 
     fn err_dotdotdot_syntax(&self, span: Span) {
-        self.struct_span_err(span, "unexpected token: `...`")
-            .span_suggestion(
-                span,
-                "use `..` for an exclusive range",
-                "..",
-                Applicability::MaybeIncorrect,
-            )
-            .span_suggestion(
-                span,
-                "or `..=` for an inclusive range",
-                "..=",
-                Applicability::MaybeIncorrect,
-            )
-            .emit();
+        self.sess.emit_err(DotDotDot { span });
     }
 
     fn err_larrow_operator(&self, span: Span) {
-        self.struct_span_err(span, "unexpected token: `<-`")
-            .span_suggestion(
-                span,
-                "if you meant to write a comparison against a negative value, add a \
-             space in between `<` and `-`",
-                "< -",
-                Applicability::MaybeIncorrect,
-            )
-            .emit();
+        self.sess.emit_err(LeftArrowOperator { span });
     }
 
     fn mk_assign_op(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
@@ -3242,17 +3099,21 @@ impl<'a> Parser<'a> {
 
     fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> P<Expr> {
         let span = lo.to(self.prev_token.span);
-        let await_expr = self.mk_expr(span, ExprKind::Await(self_arg), AttrVec::new());
+        let await_expr = self.mk_expr(span, ExprKind::Await(self_arg));
         self.recover_from_await_method_call();
         await_expr
     }
 
-    pub(crate) fn mk_expr(&self, span: Span, kind: ExprKind, attrs: AttrVec) -> P<Expr> {
+    pub(crate) fn mk_expr_with_attrs(&self, span: Span, kind: ExprKind, attrs: AttrVec) -> P<Expr> {
         P(Expr { kind, span, attrs, id: DUMMY_NODE_ID, tokens: None })
     }
 
+    pub(crate) fn mk_expr(&self, span: Span, kind: ExprKind) -> P<Expr> {
+        P(Expr { kind, span, attrs: AttrVec::new(), id: DUMMY_NODE_ID, tokens: None })
+    }
+
     pub(super) fn mk_expr_err(&self, span: Span) -> P<Expr> {
-        self.mk_expr(span, ExprKind::Err, AttrVec::new())
+        self.mk_expr(span, ExprKind::Err)
     }
 
     /// Create expression span ensuring the span of the parent node
@@ -3268,7 +3129,7 @@ impl<'a> Parser<'a> {
     fn collect_tokens_for_expr(
         &mut self,
         attrs: AttrWrapper,
-        f: impl FnOnce(&mut Self, Vec<ast::Attribute>) -> PResult<'a, P<Expr>>,
+        f: impl FnOnce(&mut Self, ast::AttrVec) -> PResult<'a, P<Expr>>,
     ) -> PResult<'a, P<Expr>> {
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
             let res = f(this, attrs)?;
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index 1acfd93d8..4d0a8b05e 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -1,9 +1,7 @@
 use super::{ForceCollect, Parser, TrailingToken};
 
 use rustc_ast::token;
-use rustc_ast::{
-    self as ast, Attribute, GenericBounds, GenericParam, GenericParamKind, WhereClause,
-};
+use rustc_ast::{self as ast, AttrVec, GenericBounds, GenericParam, GenericParamKind, WhereClause};
 use rustc_errors::{Applicability, PResult};
 use rustc_span::symbol::kw;
 
@@ -26,7 +24,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Matches `typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?`.
-    fn parse_ty_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> {
+    fn parse_ty_param(&mut self, preceding_attrs: AttrVec) -> PResult<'a, GenericParam> {
         let ident = self.parse_ident()?;
 
         // Parse optional colon and param bounds.
@@ -43,7 +41,7 @@ impl<'a> Parser<'a> {
         Ok(GenericParam {
             ident,
             id: ast::DUMMY_NODE_ID,
-            attrs: preceding_attrs.into(),
+            attrs: preceding_attrs,
             bounds,
             kind: GenericParamKind::Type { default },
             is_placeholder: false,
@@ -53,7 +51,7 @@ impl<'a> Parser<'a> {
 
     pub(crate) fn parse_const_param(
         &mut self,
-        preceding_attrs: Vec<Attribute>,
+        preceding_attrs: AttrVec,
     ) -> PResult<'a, GenericParam> {
         let const_span = self.token.span;
 
@@ -68,7 +66,7 @@ impl<'a> Parser<'a> {
         Ok(GenericParam {
             ident,
             id: ast::DUMMY_NODE_ID,
-            attrs: preceding_attrs.into(),
+            attrs: preceding_attrs,
             bounds: Vec::new(),
             kind: GenericParamKind::Const { ty, kw_span: const_span, default },
             is_placeholder: false,
@@ -109,7 +107,7 @@ impl<'a> Parser<'a> {
                         Some(ast::GenericParam {
                             ident: lifetime.ident,
                             id: lifetime.id,
-                            attrs: attrs.into(),
+                            attrs,
                             bounds,
                             kind: ast::GenericParamKind::Lifetime,
                             is_placeholder: false,
@@ -314,7 +312,6 @@ impl<'a> Parser<'a> {
                 span: lo.to(self.prev_token.span),
                 lhs_ty: ty,
                 rhs_ty,
-                id: ast::DUMMY_NODE_ID,
             }))
         } else {
             self.maybe_recover_bounds_doubled_colon(&ty)?;
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 567072925..e55b5ce71 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -8,7 +8,7 @@ use rustc_ast::token::{self, Delimiter, TokenKind};
 use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree};
 use rustc_ast::{self as ast, AttrVec, Attribute, DUMMY_NODE_ID};
 use rustc_ast::{Async, Const, Defaultness, IsAuto, Mutability, Unsafe, UseTree, UseTreeKind};
-use rustc_ast::{BindingMode, Block, FnDecl, FnSig, Param, SelfKind};
+use rustc_ast::{BindingAnnotation, Block, FnDecl, FnSig, Param, SelfKind};
 use rustc_ast::{EnumDef, FieldDef, Generics, TraitRef, Ty, TyKind, Variant, VariantData};
 use rustc_ast::{FnHeader, ForeignItem, Path, PathSegment, Visibility, VisibilityKind};
 use rustc_ast::{MacArgs, MacCall, MacDelimiter};
@@ -22,7 +22,6 @@ use rustc_span::DUMMY_SP;
 
 use std::convert::TryFrom;
 use std::mem;
-use tracing::debug;
 
 impl<'a> Parser<'a> {
     /// Parses a source module as a crate. This is the main entry point for the parser.
@@ -32,7 +31,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a `mod <foo> { ... }` or `mod <foo>;` item.
-    fn parse_item_mod(&mut self, attrs: &mut Vec<Attribute>) -> PResult<'a, ItemInfo> {
+    fn parse_item_mod(&mut self, attrs: &mut AttrVec) -> PResult<'a, ItemInfo> {
         let unsafety = self.parse_unsafety();
         self.expect_keyword(kw::Mod)?;
         let id = self.parse_ident()?;
@@ -40,9 +39,9 @@ impl<'a> Parser<'a> {
             ModKind::Unloaded
         } else {
             self.expect(&token::OpenDelim(Delimiter::Brace))?;
-            let (mut inner_attrs, items, inner_span) =
+            let (inner_attrs, items, inner_span) =
                 self.parse_mod(&token::CloseDelim(Delimiter::Brace))?;
-            attrs.append(&mut inner_attrs);
+            attrs.extend(inner_attrs);
             ModKind::Loaded(items, Inline::Yes, inner_span)
         };
         Ok((id, ItemKind::Mod(unsafety, mod_kind)))
@@ -52,7 +51,7 @@ impl<'a> Parser<'a> {
     pub fn parse_mod(
         &mut self,
         term: &TokenKind,
-    ) -> PResult<'a, (Vec<Attribute>, Vec<P<Item>>, ModSpans)> {
+    ) -> PResult<'a, (AttrVec, Vec<P<Item>>, ModSpans)> {
         let lo = self.token.span;
         let attrs = self.parse_inner_attributes()?;
 
@@ -68,7 +67,12 @@ impl<'a> Parser<'a> {
             if !self.maybe_consume_incorrect_semicolon(&items) {
                 let msg = &format!("expected item, found {token_str}");
                 let mut err = self.struct_span_err(self.token.span, msg);
-                err.span_label(self.token.span, "expected item");
+                let label = if self.is_kw_followed_by_ident(kw::Let) {
+                    "consider using `const` or `static` instead of `let` for global variables"
+                } else {
+                    "expected item"
+                };
+                err.span_label(self.token.span, label);
                 return Err(err);
             }
         }
@@ -129,7 +133,7 @@ impl<'a> Parser<'a> {
 
     fn parse_item_common_(
         &mut self,
-        mut attrs: Vec<Attribute>,
+        mut attrs: AttrVec,
         mac_allowed: bool,
         attrs_allowed: bool,
         fn_parse_mode: FnParseMode,
@@ -193,7 +197,7 @@ impl<'a> Parser<'a> {
     /// Parses one of the items allowed by the flags.
     fn parse_item_kind(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         macros_allowed: bool,
         lo: Span,
         vis: &Visibility,
@@ -271,7 +275,10 @@ impl<'a> Parser<'a> {
             // MACRO_RULES ITEM
             self.parse_item_macro_rules(vis, has_bang)?
         } else if self.isnt_macro_invocation()
-            && (self.token.is_ident_named(sym::import) || self.token.is_ident_named(sym::using))
+            && (self.token.is_ident_named(sym::import)
+                || self.token.is_ident_named(sym::using)
+                || self.token.is_ident_named(sym::include)
+                || self.token.is_ident_named(sym::require))
         {
             return self.recover_import_as_use();
         } else if self.isnt_macro_invocation() && vis.kind.is_pub() {
@@ -279,7 +286,7 @@ impl<'a> Parser<'a> {
             return Ok(None);
         } else if macros_allowed && self.check_path() {
             // MACRO INVOCATION ITEM
-            (Ident::empty(), ItemKind::MacCall(self.parse_item_macro(vis)?))
+            (Ident::empty(), ItemKind::MacCall(P(self.parse_item_macro(vis)?)))
         } else {
             return Ok(None);
         };
@@ -526,7 +533,7 @@ impl<'a> Parser<'a> {
     /// ```
     fn parse_item_impl(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         defaultness: Defaultness,
     ) -> PResult<'a, ItemInfo> {
         let unsafety = self.parse_unsafety();
@@ -653,12 +660,12 @@ impl<'a> Parser<'a> {
 
     fn parse_item_list<T>(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         mut parse_item: impl FnMut(&mut Parser<'a>) -> PResult<'a, Option<Option<T>>>,
     ) -> PResult<'a, Vec<T>> {
         let open_brace_span = self.token.span;
         self.expect(&token::OpenDelim(Delimiter::Brace))?;
-        attrs.append(&mut self.parse_inner_attributes()?);
+        attrs.extend(self.parse_inner_attributes()?);
 
         let mut items = Vec::new();
         while !self.eat(&token::CloseDelim(Delimiter::Brace)) {
@@ -667,14 +674,55 @@ impl<'a> Parser<'a> {
             }
             match parse_item(self) {
                 Ok(None) => {
+                    let is_unnecessary_semicolon = !items.is_empty()
+                        // When the close delim is `)` in a case like the following, `token.kind` is expected to be `token::CloseDelim(Delimiter::Parenthesis)`,
+                        // but the actual `token.kind` is `token::CloseDelim(Delimiter::Bracket)`.
+                        // This is because the `token.kind` of the close delim is treated as the same as
+                        // that of the open delim in `TokenTreesReader::parse_token_tree`, even if the delimiters of them are different.
+                        // Therefore, `token.kind` should not be compared here.
+                        //
+                        // issue-60075.rs
+                        // ```
+                        // trait T {
+                        //     fn qux() -> Option<usize> {
+                        //         let _ = if true {
+                        //         });
+                        //          ^ this close delim
+                        //         Some(4)
+                        //     }
+                        // ```
+                        && self
+                            .span_to_snippet(self.prev_token.span)
+                            .map_or(false, |snippet| snippet == "}")
+                        && self.token.kind == token::Semi;
+                    let semicolon_span = self.token.span;
                     // We have to bail or we'll potentially never make progress.
                     let non_item_span = self.token.span;
+                    let is_let = self.token.is_keyword(kw::Let);
+
+                    let mut err = self.struct_span_err(non_item_span, "non-item in item list");
                     self.consume_block(Delimiter::Brace, ConsumeClosingDelim::Yes);
-                    self.struct_span_err(non_item_span, "non-item in item list")
-                        .span_label(open_brace_span, "item list starts here")
-                        .span_label(non_item_span, "non-item starts here")
-                        .span_label(self.prev_token.span, "item list ends here")
-                        .emit();
+                    if is_let {
+                        err.span_suggestion(
+                            non_item_span,
+                            "consider using `const` instead of `let` for associated const",
+                            "const",
+                            Applicability::MachineApplicable,
+                        );
+                    } else {
+                        err.span_label(open_brace_span, "item list starts here")
+                            .span_label(non_item_span, "non-item starts here")
+                            .span_label(self.prev_token.span, "item list ends here");
+                    }
+                    if is_unnecessary_semicolon {
+                        err.span_suggestion(
+                            semicolon_span,
+                            "consider removing this semicolon",
+                            "",
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
+                    err.emit();
                     break;
                 }
                 Ok(Some(item)) => items.extend(item),
@@ -737,7 +785,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses `unsafe? auto? trait Foo { ... }` or `trait Foo = Bar;`.
-    fn parse_item_trait(&mut self, attrs: &mut Vec<Attribute>, lo: Span) -> PResult<'a, ItemInfo> {
+    fn parse_item_trait(&mut self, attrs: &mut AttrVec, lo: Span) -> PResult<'a, ItemInfo> {
         let unsafety = self.parse_unsafety();
         // Parse optional `auto` prefix.
         let is_auto = if self.eat_keyword(kw::Auto) { IsAuto::Yes } else { IsAuto::No };
@@ -1023,7 +1071,7 @@ impl<'a> Parser<'a> {
     /// ```
     fn parse_item_foreign_mod(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         mut unsafety: Unsafe,
     ) -> PResult<'a, ItemInfo> {
         let abi = self.parse_abi(); // ABI?
@@ -1124,6 +1172,16 @@ impl<'a> Parser<'a> {
                     Applicability::MaybeIncorrect,
                 )
                 .emit();
+        } else if self.eat_keyword(kw::Let) {
+            let span = self.prev_token.span;
+            self.struct_span_err(const_span.to(span), "`const` and `let` are mutually exclusive")
+                .span_suggestion(
+                    const_span.to(span),
+                    "remove `let`",
+                    "const",
+                    Applicability::MaybeIncorrect,
+                )
+                .emit();
         }
     }
 
@@ -1131,7 +1189,7 @@ impl<'a> Parser<'a> {
     fn recover_const_impl(
         &mut self,
         const_span: Span,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         defaultness: Defaultness,
     ) -> PResult<'a, ItemInfo> {
         let impl_span = self.token.span;
@@ -1179,10 +1237,11 @@ impl<'a> Parser<'a> {
 
         // Parse the type of a `const` or `static mut?` item.
         // That is, the `":" $ty` fragment.
-        let ty = if self.eat(&token::Colon) {
-            self.parse_ty()?
-        } else {
-            self.recover_missing_const_type(id, m)
+        let ty = match (self.eat(&token::Colon), self.check(&token::Eq) | self.check(&token::Semi))
+        {
+            // If there wasn't a `:` or the colon was followed by a `=` or `;` recover a missing type.
+            (true, false) => self.parse_ty()?,
+            (colon, _) => self.recover_missing_const_type(colon, m),
         };
 
         let expr = if self.eat(&token::Eq) { Some(self.parse_expr()?) } else { None };
@@ -1190,9 +1249,9 @@ impl<'a> Parser<'a> {
         Ok((id, ty, expr))
     }
 
-    /// We were supposed to parse `:` but the `:` was missing.
+    /// We were supposed to parse `":" $ty` but the `:` or the type was missing.
     /// This means that the type is missing.
-    fn recover_missing_const_type(&mut self, id: Ident, m: Option<Mutability>) -> P<Ty> {
+    fn recover_missing_const_type(&mut self, colon_present: bool, m: Option<Mutability>) -> P<Ty> {
         // Construct the error and stash it away with the hope
         // that typeck will later enrich the error with a type.
         let kind = match m {
@@ -1200,18 +1259,25 @@ impl<'a> Parser<'a> {
             Some(Mutability::Not) => "static",
             None => "const",
         };
-        let mut err = self.struct_span_err(id.span, &format!("missing type for `{kind}` item"));
+
+        let colon = match colon_present {
+            true => "",
+            false => ":",
+        };
+
+        let span = self.prev_token.span.shrink_to_hi();
+        let mut err = self.struct_span_err(span, &format!("missing type for `{kind}` item"));
         err.span_suggestion(
-            id.span,
+            span,
             "provide a type for the item",
-            format!("{id}: <type>"),
+            format!("{colon} <type>"),
             Applicability::HasPlaceholders,
         );
-        err.stash(id.span, StashKey::ItemNoType);
+        err.stash(span, StashKey::ItemNoType);
 
         // The user intended that the type be inferred,
         // so treat this as if the user wrote e.g. `const A: _ = expr;`.
-        P(Ty { kind: TyKind::Infer, span: id.span, id: ast::DUMMY_NODE_ID, tokens: None })
+        P(Ty { kind: TyKind::Infer, span, id: ast::DUMMY_NODE_ID, tokens: None })
     }
 
     /// Parses an enum declaration.
@@ -1281,7 +1347,7 @@ impl<'a> Parser<'a> {
                     ident,
                     vis,
                     id: DUMMY_NODE_ID,
-                    attrs: variant_attrs.into(),
+                    attrs: variant_attrs,
                     data: struct_def,
                     disr_expr,
                     span: vlo.to(this.prev_token.span),
@@ -1438,7 +1504,7 @@ impl<'a> Parser<'a> {
                         ident: None,
                         id: DUMMY_NODE_ID,
                         ty,
-                        attrs: attrs.into(),
+                        attrs,
                         is_placeholder: false,
                     },
                     TrailingToken::MaybeComma,
@@ -1464,13 +1530,24 @@ impl<'a> Parser<'a> {
         adt_ty: &str,
         lo: Span,
         vis: Visibility,
-        attrs: Vec<Attribute>,
+        attrs: AttrVec,
     ) -> PResult<'a, FieldDef> {
         let mut seen_comma: bool = false;
         let a_var = self.parse_name_and_ty(adt_ty, lo, vis, attrs)?;
         if self.token == token::Comma {
             seen_comma = true;
         }
+        if self.eat(&token::Semi) {
+            let sp = self.prev_token.span;
+            let mut err = self.struct_span_err(sp, format!("{adt_ty} fields are separated by `,`"));
+            err.span_suggestion_short(
+                sp,
+                "replace `;` with `,`",
+                ",",
+                Applicability::MachineApplicable,
+            );
+            return Err(err);
+        }
         match self.token.kind {
             token::Comma => {
                 self.bump();
@@ -1528,8 +1605,12 @@ impl<'a> Parser<'a> {
                     }
                 }
 
-                if self.token.is_ident() {
-                    // This is likely another field; emit the diagnostic and keep going
+                if self.token.is_ident()
+                    || (self.token.kind == TokenKind::Pound
+                        && (self.look_ahead(1, |t| t == &token::OpenDelim(Delimiter::Bracket))))
+                {
+                    // This is likely another field, TokenKind::Pound is used for `#[..]` attribute for next field,
+                    // emit the diagnostic and keep going
                     err.span_suggestion(
                         sp,
                         "try adding a comma",
@@ -1590,7 +1671,7 @@ impl<'a> Parser<'a> {
         adt_ty: &str,
         lo: Span,
         vis: Visibility,
-        attrs: Vec<Attribute>,
+        attrs: AttrVec,
     ) -> PResult<'a, FieldDef> {
         let name = self.parse_field_ident(adt_ty, lo)?;
         self.expect_field_ty_separator()?;
@@ -1624,7 +1705,7 @@ impl<'a> Parser<'a> {
             vis,
             id: DUMMY_NODE_ID,
             ty,
-            attrs: attrs.into(),
+            attrs,
             is_placeholder: false,
         })
     }
@@ -1643,7 +1724,7 @@ impl<'a> Parser<'a> {
                 // We use `parse_fn` to get a span for the function
                 let fn_parse_mode = FnParseMode { req_name: |_| true, req_body: true };
                 if let Err(mut db) =
-                    self.parse_fn(&mut Vec::new(), fn_parse_mode, lo, &inherited_vis)
+                    self.parse_fn(&mut AttrVec::new(), fn_parse_mode, lo, &inherited_vis)
                 {
                     db.delay_as_bug();
                 }
@@ -1919,7 +2000,7 @@ impl<'a> Parser<'a> {
     /// Parse a function starting from the front matter (`const ...`) to the body `{ ... }` or `;`.
     fn parse_fn(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         fn_parse_mode: FnParseMode,
         sig_lo: Span,
         vis: &Visibility,
@@ -1942,7 +2023,7 @@ impl<'a> Parser<'a> {
     /// or e.g. a block when the function is a provided one.
     fn parse_fn_body(
         &mut self,
-        attrs: &mut Vec<Attribute>,
+        attrs: &mut AttrVec,
         ident: &Ident,
         sig_hi: &mut Span,
         req_body: bool,
@@ -1957,7 +2038,7 @@ impl<'a> Parser<'a> {
             // Include the trailing semicolon in the span of the signature
             self.expect_semi()?;
             *sig_hi = self.prev_token.span;
-            (Vec::new(), None)
+            (AttrVec::new(), None)
         } else if self.check(&token::OpenDelim(Delimiter::Brace)) || self.token.is_whole_block() {
             self.parse_inner_attrs_and_block().map(|(attrs, body)| (attrs, Some(body)))?
         } else if self.token.kind == token::Eq {
@@ -1974,7 +2055,7 @@ impl<'a> Parser<'a> {
                     Applicability::MachineApplicable,
                 )
                 .emit();
-            (Vec::new(), Some(self.mk_block_err(span)))
+            (AttrVec::new(), Some(self.mk_block_err(span)))
         } else {
             let expected = if req_body {
                 &[token::OpenDelim(Delimiter::Brace)][..]
@@ -1991,7 +2072,7 @@ impl<'a> Parser<'a> {
                     return Err(err);
                 }
             }
-            (Vec::new(), None)
+            (AttrVec::new(), None)
         };
         attrs.extend(inner_attrs);
         Ok(body)
@@ -2220,7 +2301,7 @@ impl<'a> Parser<'a> {
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
             // Possibly parse `self`. Recover if we parsed it and it wasn't allowed here.
             if let Some(mut param) = this.parse_self_param()? {
-                param.attrs = attrs.into();
+                param.attrs = attrs;
                 let res = if first_param { Ok(param) } else { this.recover_bad_self_param(param) };
                 return Ok((res?, TrailingToken::None));
             }
@@ -2249,7 +2330,7 @@ impl<'a> Parser<'a> {
                 (pat, this.parse_ty_for_param()?)
             } else {
                 debug!("parse_param_general ident_to_pat");
-                let parser_snapshot_before_ty = this.clone();
+                let parser_snapshot_before_ty = this.create_snapshot_for_diagnostic();
                 this.eat_incorrect_doc_comment_for_param_type();
                 let mut ty = this.parse_ty_for_param();
                 if ty.is_ok()
@@ -2263,7 +2344,7 @@ impl<'a> Parser<'a> {
                 match ty {
                     Ok(ty) => {
                         let ident = Ident::new(kw::Empty, this.prev_token.span);
-                        let bm = BindingMode::ByValue(Mutability::Not);
+                        let bm = BindingAnnotation::NONE;
                         let pat = this.mk_pat_ident(ty.span, bm, ident);
                         (pat, ty)
                     }
@@ -2272,23 +2353,16 @@ impl<'a> Parser<'a> {
                     // Recover from attempting to parse the argument as a type without pattern.
                     Err(err) => {
                         err.cancel();
-                        *this = parser_snapshot_before_ty;
+                        this.restore_snapshot(parser_snapshot_before_ty);
                         this.recover_arg_parse()?
                     }
                 }
             };
 
-            let span = lo.until(this.token.span);
+            let span = lo.to(this.prev_token.span);
 
             Ok((
-                Param {
-                    attrs: attrs.into(),
-                    id: ast::DUMMY_NODE_ID,
-                    is_placeholder: false,
-                    pat,
-                    span,
-                    ty,
-                },
+                Param { attrs, id: ast::DUMMY_NODE_ID, is_placeholder: false, pat, span, ty },
                 TrailingToken::None,
             ))
         })
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 0c523ad22..4cb198561 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -37,7 +37,6 @@ use rustc_errors::{
 use rustc_session::parse::ParseSess;
 use rustc_span::source_map::{Span, DUMMY_SP};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use tracing::debug;
 
 use std::ops::Range;
 use std::{cmp, mem, slice};
@@ -171,7 +170,7 @@ pub struct ClosureSpans {
 /// attribute, we parse a nested AST node that has `#[cfg]` or `#[cfg_attr]`
 /// In this case, we use a `ReplaceRange` to replace the entire inner AST node
 /// with `FlatToken::AttrTarget`, allowing us to perform eager cfg-expansion
-/// on an `AttrAnnotatedTokenStream`
+/// on an `AttrTokenStream`.
 ///
 /// 2. When we parse an inner attribute while collecting tokens. We
 /// remove inner attributes from the token stream entirely, and
@@ -184,7 +183,7 @@ pub type ReplaceRange = (Range<u32>, Vec<(FlatToken, Spacing)>);
 
 /// Controls how we capture tokens. Capturing can be expensive,
 /// so we try to avoid performing capturing in cases where
-/// we will never need an `AttrAnnotatedTokenStream`
+/// we will never need an `AttrTokenStream`.
 #[derive(Copy, Clone)]
 pub enum Capturing {
     /// We aren't performing any capturing - this is the default mode.
@@ -238,7 +237,7 @@ struct TokenCursor {
     // the trailing `>>` token. The `break_last_token`
     // field is used to track this token - it gets
     // appended to the captured stream when
-    // we evaluate a `LazyTokenStream`
+    // we evaluate a `LazyAttrTokenStream`.
     break_last_token: bool,
 }
 
@@ -281,7 +280,7 @@ impl TokenCursor {
                         if delim != Delimiter::Invisible {
                             return (Token::new(token::OpenDelim(delim), sp.open), Spacing::Alone);
                         }
-                        // No open delimeter to return; continue on to the next iteration.
+                        // No open delimiter to return; continue on to the next iteration.
                     }
                 };
             } else if let Some(frame) = self.stack.pop() {
@@ -1116,10 +1115,14 @@ impl<'a> Parser<'a> {
         let (attrs, blk) = self.parse_inner_attrs_and_block()?;
         let anon_const = AnonConst {
             id: DUMMY_NODE_ID,
-            value: self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()),
+            value: self.mk_expr(blk.span, ExprKind::Block(blk, None)),
         };
         let blk_span = anon_const.value.span;
-        Ok(self.mk_expr(span.to(blk_span), ExprKind::ConstBlock(anon_const), AttrVec::from(attrs)))
+        Ok(self.mk_expr_with_attrs(
+            span.to(blk_span),
+            ExprKind::ConstBlock(anon_const),
+            AttrVec::from(attrs),
+        ))
     }
 
     /// Parses mutability (`mut` or nothing).
@@ -1295,7 +1298,11 @@ impl<'a> Parser<'a> {
                 self.bump(); // `in`
                 let path = self.parse_path(PathStyle::Mod)?; // `path`
                 self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)`
-                let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
+                let vis = VisibilityKind::Restricted {
+                    path: P(path),
+                    id: ast::DUMMY_NODE_ID,
+                    shorthand: false,
+                };
                 return Ok(Visibility {
                     span: lo.to(self.prev_token.span),
                     kind: vis,
@@ -1308,7 +1315,11 @@ impl<'a> Parser<'a> {
                 self.bump(); // `(`
                 let path = self.parse_path(PathStyle::Mod)?; // `crate`/`super`/`self`
                 self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; // `)`
-                let vis = VisibilityKind::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
+                let vis = VisibilityKind::Restricted {
+                    path: P(path),
+                    id: ast::DUMMY_NODE_ID,
+                    shorthand: true,
+                };
                 return Ok(Visibility {
                     span: lo.to(self.prev_token.span),
                     kind: vis,
@@ -1371,7 +1382,7 @@ impl<'a> Parser<'a> {
         match self.parse_str_lit() {
             Ok(str_lit) => Some(str_lit),
             Err(Some(lit)) => match lit.kind {
-                ast::LitKind::Err(_) => None,
+                ast::LitKind::Err => None,
                 _ => {
                     self.struct_span_err(lit.span, "non-string ABI literal")
                         .span_suggestion(
@@ -1453,11 +1464,11 @@ pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &Pa
     }
 }
 
-/// A helper struct used when building an `AttrAnnotatedTokenStream` from
-/// a `LazyTokenStream`. Both delimiter and non-delimited tokens
+/// A helper struct used when building an `AttrTokenStream` from
+/// a `LazyAttrTokenStream`. Both delimiter and non-delimited tokens
 /// are stored as `FlatToken::Token`. A vector of `FlatToken`s
-/// is then 'parsed' to build up an `AttrAnnotatedTokenStream` with nested
-/// `AttrAnnotatedTokenTree::Delimited` tokens
+/// is then 'parsed' to build up an `AttrTokenStream` with nested
+/// `AttrTokenTree::Delimited` tokens.
 #[derive(Debug, Clone)]
 pub enum FlatToken {
     /// A token - this holds both delimiter (e.g. '{' and '}')
@@ -1465,11 +1476,11 @@ pub enum FlatToken {
     Token(Token),
     /// Holds the `AttributesData` for an AST node. The
     /// `AttributesData` is inserted directly into the
-    /// constructed `AttrAnnotatedTokenStream` as
-    /// an `AttrAnnotatedTokenTree::Attributes`
+    /// constructed `AttrTokenStream` as
+    /// an `AttrTokenTree::Attributes`.
     AttrTarget(AttributesData),
     /// A special 'empty' token that is ignored during the conversion
-    /// to an `AttrAnnotatedTokenStream`. This is used to simplify the
+    /// to an `AttrTokenStream`. This is used to simplify the
     /// handling of replace ranges.
     Empty,
 }
diff --git a/compiler/rustc_parse/src/parser/nonterminal.rs b/compiler/rustc_parse/src/parser/nonterminal.rs
index e215b6872..103dd8012 100644
--- a/compiler/rustc_parse/src/parser/nonterminal.rs
+++ b/compiler/rustc_parse/src/parser/nonterminal.rs
@@ -66,18 +66,18 @@ impl<'a> Parser<'a> {
             },
             NonterminalKind::PatParam { .. } | NonterminalKind::PatWithOr { .. } => {
                 match token.kind {
-                token::Ident(..) |                  // box, ref, mut, and other identifiers (can stricten)
-                token::OpenDelim(Delimiter::Parenthesis) |    // tuple pattern
-                token::OpenDelim(Delimiter::Bracket) |  // slice pattern
-                token::BinOp(token::And) |          // reference
-                token::BinOp(token::Minus) |        // negative literal
-                token::AndAnd |                     // double reference
-                token::Literal(..) |                // literal
-                token::DotDot |                     // range pattern (future compat)
-                token::DotDotDot |                  // range pattern (future compat)
-                token::ModSep |                     // path
-                token::Lt |                         // path (UFCS constant)
-                token::BinOp(token::Shl) => true,   // path (double UFCS)
+                token::Ident(..) |                          // box, ref, mut, and other identifiers (can stricten)
+                token::OpenDelim(Delimiter::Parenthesis) |  // tuple pattern
+                token::OpenDelim(Delimiter::Bracket) |      // slice pattern
+                token::BinOp(token::And) |                  // reference
+                token::BinOp(token::Minus) |                // negative literal
+                token::AndAnd |                             // double reference
+                token::Literal(..) |                        // literal
+                token::DotDot |                             // range pattern (future compat)
+                token::DotDotDot |                          // range pattern (future compat)
+                token::ModSep |                             // path
+                token::Lt |                                 // path (UFCS constant)
+                token::BinOp(token::Shl) => true,           // path (double UFCS)
                 // leading vert `|` or-pattern
                 token::BinOp(token::Or) =>  matches!(kind, NonterminalKind::PatWithOr {..}),
                 token::Interpolated(ref nt) => may_be_ident(nt),
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index ba77a3958..120a3c267 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -1,10 +1,11 @@
 use super::{ForceCollect, Parser, PathStyle, TrailingToken};
+use crate::parser::diagnostics::RemoveLet;
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor};
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter};
 use rustc_ast::{
-    self as ast, AttrVec, Attribute, BindingMode, Expr, ExprKind, MacCall, Mutability, Pat,
+    self as ast, AttrVec, BindingAnnotation, ByRef, Expr, ExprKind, MacCall, Mutability, Pat,
     PatField, PatKind, Path, QSelf, RangeEnd, RangeSyntax,
 };
 use rustc_ast_pretty::pprust;
@@ -320,7 +321,13 @@ impl<'a> Parser<'a> {
         maybe_recover_from_interpolated_ty_qpath!(self, true);
         maybe_whole!(self, NtPat, |x| x);
 
-        let lo = self.token.span;
+        let mut lo = self.token.span;
+
+        if self.token.is_keyword(kw::Let) && self.look_ahead(1, |tok| tok.can_begin_pattern()) {
+            self.bump();
+            self.sess.emit_err(RemoveLet { span: lo });
+            lo = self.token.span;
+        }
 
         let pat = if self.check(&token::BinOp(token::And)) || self.token.kind == token::AndAnd {
             self.parse_pat_deref(expected)?
@@ -353,7 +360,7 @@ impl<'a> Parser<'a> {
         } else if self.eat_keyword(kw::Ref) {
             // Parse ref ident @ pat / ref mut ident @ pat
             let mutbl = self.parse_mutability();
-            self.parse_pat_ident(BindingMode::ByRef(mutbl))?
+            self.parse_pat_ident(BindingAnnotation(ByRef::Yes, mutbl))?
         } else if self.eat_keyword(kw::Box) {
             self.parse_pat_box()?
         } else if self.check_inline_const(0) {
@@ -369,7 +376,7 @@ impl<'a> Parser<'a> {
             // Parse `ident @ pat`
             // This can give false positives and parse nullary enums,
             // they are dealt with later in resolve.
-            self.parse_pat_ident(BindingMode::ByValue(Mutability::Not))?
+            self.parse_pat_ident(BindingAnnotation::NONE)?
         } else if self.is_start_of_pat_with_path() {
             // Parse pattern starting with a path
             let (qself, path) = if self.eat_lt() {
@@ -385,7 +392,7 @@ impl<'a> Parser<'a> {
             if qself.is_none() && self.check(&token::Not) {
                 self.parse_pat_mac_invoc(path)?
             } else if let Some(form) = self.parse_range_end() {
-                let begin = self.mk_expr(span, ExprKind::Path(qself, path), AttrVec::new());
+                let begin = self.mk_expr(span, ExprKind::Path(qself, path));
                 self.parse_pat_range_begin_with(begin, form)?
             } else if self.check(&token::OpenDelim(Delimiter::Brace)) {
                 self.parse_pat_struct(qself, path)?
@@ -578,7 +585,8 @@ impl<'a> Parser<'a> {
         let mut pat = self.parse_pat_no_top_alt(Some("identifier"))?;
 
         // If we don't have `mut $ident (@ pat)?`, error.
-        if let PatKind::Ident(BindingMode::ByValue(m @ Mutability::Not), ..) = &mut pat.kind {
+        if let PatKind::Ident(BindingAnnotation(ByRef::No, m @ Mutability::Not), ..) = &mut pat.kind
+        {
             // Don't recurse into the subpattern.
             // `mut` on the outer binding doesn't affect the inner bindings.
             *m = Mutability::Mut;
@@ -604,7 +612,7 @@ impl<'a> Parser<'a> {
             )
             .emit();
 
-        self.parse_pat_ident(BindingMode::ByRef(Mutability::Mut))
+        self.parse_pat_ident(BindingAnnotation::REF_MUT)
     }
 
     /// Turn all by-value immutable bindings in a pattern into mutable bindings.
@@ -613,7 +621,8 @@ impl<'a> Parser<'a> {
         struct AddMut(bool);
         impl MutVisitor for AddMut {
             fn visit_pat(&mut self, pat: &mut P<Pat>) {
-                if let PatKind::Ident(BindingMode::ByValue(m @ Mutability::Not), ..) = &mut pat.kind
+                if let PatKind::Ident(BindingAnnotation(ByRef::No, m @ Mutability::Not), ..) =
+                    &mut pat.kind
                 {
                     self.0 = true;
                     *m = Mutability::Mut;
@@ -665,7 +674,7 @@ impl<'a> Parser<'a> {
     fn parse_pat_mac_invoc(&mut self, path: Path) -> PResult<'a, PatKind> {
         self.bump();
         let args = self.parse_mac_args()?;
-        let mac = MacCall { path, args, prior_type_ascription: self.last_type_ascription };
+        let mac = P(MacCall { path, args, prior_type_ascription: self.last_type_ascription });
         Ok(PatKind::MacCall(mac))
     }
 
@@ -807,7 +816,7 @@ impl<'a> Parser<'a> {
                 (None, self.parse_path(PathStyle::Expr)?)
             };
             let hi = self.prev_token.span;
-            Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path), AttrVec::new()))
+            Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path)))
         } else {
             self.parse_literal_maybe_minus()
         }
@@ -838,7 +847,7 @@ impl<'a> Parser<'a> {
     /// Parses `ident` or `ident @ pat`.
     /// Used by the copy foo and ref foo patterns to give a good
     /// error message when parsing mistakes like `ref foo(a, b)`.
-    fn parse_pat_ident(&mut self, binding_mode: BindingMode) -> PResult<'a, PatKind> {
+    fn parse_pat_ident(&mut self, binding_annotation: BindingAnnotation) -> PResult<'a, PatKind> {
         let ident = self.parse_ident()?;
         let sub = if self.eat(&token::At) {
             Some(self.parse_pat_no_top_alt(Some("binding pattern"))?)
@@ -856,7 +865,7 @@ impl<'a> Parser<'a> {
                 .struct_span_err(self.prev_token.span, "expected identifier, found enum pattern"));
         }
 
-        Ok(PatKind::Ident(binding_mode, ident, sub))
+        Ok(PatKind::Ident(binding_annotation, ident, sub))
     }
 
     /// Parse a struct ("record") pattern (e.g. `Foo { ... }` or `Foo::Bar { ... }`).
@@ -936,11 +945,7 @@ impl<'a> Parser<'a> {
                 None
             };
 
-            Ok(PatKind::Ident(
-                BindingMode::ByValue(Mutability::Not),
-                Ident::new(kw::Box, box_span),
-                sub,
-            ))
+            Ok(PatKind::Ident(BindingAnnotation::NONE, Ident::new(kw::Box, box_span), sub))
         } else {
             let pat = self.parse_pat_with_range_pat(false, None)?;
             self.sess.gated_spans.gate(sym::box_patterns, box_span.to(self.prev_token.span));
@@ -1093,7 +1098,7 @@ impl<'a> Parser<'a> {
             .emit();
     }
 
-    fn parse_pat_field(&mut self, lo: Span, attrs: Vec<Attribute>) -> PResult<'a, PatField> {
+    fn parse_pat_field(&mut self, lo: Span, attrs: AttrVec) -> PResult<'a, PatField> {
         // Check if a colon exists one ahead. This means we're parsing a fieldname.
         let hi;
         let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
@@ -1117,14 +1122,12 @@ impl<'a> Parser<'a> {
             let fieldname = self.parse_field_name()?;
             hi = self.prev_token.span;
 
-            let bind_type = match (is_ref, is_mut) {
-                (true, true) => BindingMode::ByRef(Mutability::Mut),
-                (true, false) => BindingMode::ByRef(Mutability::Not),
-                (false, true) => BindingMode::ByValue(Mutability::Mut),
-                (false, false) => BindingMode::ByValue(Mutability::Not),
+            let mutability = match is_mut {
+                false => Mutability::Not,
+                true => Mutability::Mut,
             };
-
-            let fieldpat = self.mk_pat_ident(boxed_span.to(hi), bind_type, fieldname);
+            let ann = BindingAnnotation(ByRef::from(is_ref), mutability);
+            let fieldpat = self.mk_pat_ident(boxed_span.to(hi), ann, fieldname);
             let subpat =
                 if is_box { self.mk_pat(lo.to(hi), PatKind::Box(fieldpat)) } else { fieldpat };
             (subpat, fieldname, true)
@@ -1134,15 +1137,15 @@ impl<'a> Parser<'a> {
             ident: fieldname,
             pat: subpat,
             is_shorthand,
-            attrs: attrs.into(),
+            attrs,
             id: ast::DUMMY_NODE_ID,
             span: lo.to(hi),
             is_placeholder: false,
         })
     }
 
-    pub(super) fn mk_pat_ident(&self, span: Span, bm: BindingMode, ident: Ident) -> P<Pat> {
-        self.mk_pat(span, PatKind::Ident(bm, ident, None))
+    pub(super) fn mk_pat_ident(&self, span: Span, ann: BindingAnnotation, ident: Ident) -> P<Pat> {
+        self.mk_pat(span, PatKind::Ident(ann, ident, None))
     }
 
     pub(super) fn mk_pat(&self, span: Span, kind: PatKind) -> P<Pat> {
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 5cf1758c3..fdc1af27f 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -13,7 +13,6 @@ use rustc_span::source_map::{BytePos, Span};
 use rustc_span::symbol::{kw, sym, Ident};
 
 use std::mem;
-use tracing::debug;
 
 /// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
@@ -527,7 +526,7 @@ impl<'a> Parser<'a> {
                         Ok(ident_gen_args) => ident_gen_args,
                         Err(()) => return Ok(Some(AngleBracketedArg::Arg(arg))),
                     };
-                    if binder.is_some() {
+                    if binder {
                         // FIXME(compiler-errors): this could be improved by suggesting lifting
                         // this up to the trait, at least before this becomes real syntax.
                         // e.g. `Trait<for<'a> Assoc = Ty>` -> `for<'a> Trait<Assoc = Ty>`
@@ -652,12 +651,7 @@ impl<'a> Parser<'a> {
     pub(super) fn parse_const_arg(&mut self) -> PResult<'a, AnonConst> {
         // Parse const argument.
         let value = if let token::OpenDelim(Delimiter::Brace) = self.token.kind {
-            self.parse_block_expr(
-                None,
-                self.token.span,
-                BlockCheckMode::Default,
-                ast::AttrVec::new(),
-            )?
+            self.parse_block_expr(None, self.token.span, BlockCheckMode::Default)?
         } else {
             self.handle_unambiguous_unbraced_const_arg()?
         };
@@ -725,28 +719,24 @@ impl<'a> Parser<'a> {
 
     /// Given a arg inside of generics, we try to destructure it as if it were the LHS in
     /// `LHS = ...`, i.e. an associated type binding.
-    /// This returns (optionally, if they are present) any `for<'a, 'b>` binder args, the
+    /// This returns a bool indicating if there are any `for<'a, 'b>` binder args, the
     /// identifier, and any GAT arguments.
     fn get_ident_from_generic_arg(
         &self,
         gen_arg: &GenericArg,
-    ) -> Result<(Option<Vec<ast::GenericParam>>, Ident, Option<GenericArgs>), ()> {
+    ) -> Result<(bool, Ident, Option<GenericArgs>), ()> {
         if let GenericArg::Type(ty) = gen_arg {
             if let ast::TyKind::Path(qself, path) = &ty.kind
                 && qself.is_none()
                 && let [seg] = path.segments.as_slice()
             {
-                return Ok((None, seg.ident, seg.args.as_deref().cloned()));
+                return Ok((false, seg.ident, seg.args.as_deref().cloned()));
             } else if let ast::TyKind::TraitObject(bounds, ast::TraitObjectSyntax::None) = &ty.kind
                 && let [ast::GenericBound::Trait(trait_ref, ast::TraitBoundModifier::None)] =
                     bounds.as_slice()
                 && let [seg] = trait_ref.trait_ref.path.segments.as_slice()
             {
-                return Ok((
-                    Some(trait_ref.bound_generic_params.clone()),
-                    seg.ident,
-                    seg.args.as_deref().cloned(),
-                ));
+                return Ok((true, seg.ident, seg.args.as_deref().cloned()));
             }
         }
         Err(())
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 51bd9d2d3..3d957406b 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -1,5 +1,7 @@
 use super::attr::DEFAULT_INNER_ATTR_FORBIDDEN;
-use super::diagnostics::{AttemptLocalParseRecovery, Error};
+use super::diagnostics::{
+    AttemptLocalParseRecovery, Error, InvalidVariableDeclaration, InvalidVariableDeclarationSub,
+};
 use super::expr::LhsExpr;
 use super::pat::RecoverComma;
 use super::path::PathStyle;
@@ -34,7 +36,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// If `force_capture` is true, forces collection of tokens regardless of whether
+    /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of whether
     /// or not we have attributes
     pub(crate) fn parse_stmt_without_recovery(
         &mut self,
@@ -55,18 +57,25 @@ impl<'a> Parser<'a> {
             return Ok(Some(stmt.into_inner()));
         }
 
+        if self.token.is_keyword(kw::Mut) && self.is_keyword_ahead(1, &[kw::Let]) {
+            self.bump();
+            let mut_let_span = lo.to(self.token.span);
+            self.sess.emit_err(InvalidVariableDeclaration {
+                span: mut_let_span,
+                sub: InvalidVariableDeclarationSub::SwitchMutLetOrder(mut_let_span),
+            });
+        }
+
         Ok(Some(if self.token.is_keyword(kw::Let) {
             self.parse_local_mk(lo, attrs, capture_semi, force_collect)?
         } else if self.is_kw_followed_by_ident(kw::Mut) {
-            self.recover_stmt_local(lo, attrs, "missing keyword", "let mut")?
+            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::MissingLet)?
         } else if self.is_kw_followed_by_ident(kw::Auto) {
             self.bump(); // `auto`
-            let msg = "write `let` instead of `auto` to introduce a new variable";
-            self.recover_stmt_local(lo, attrs, msg, "let")?
+            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotAuto)?
         } else if self.is_kw_followed_by_ident(sym::var) {
             self.bump(); // `var`
-            let msg = "write `let` instead of `var` to introduce a new variable";
-            self.recover_stmt_local(lo, attrs, msg, "let")?
+            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotVar)?
         } else if self.check_path() && !self.token.is_qpath_start() && !self.is_path_start_item() {
             // We have avoided contextual keywords like `union`, items with `crate` visibility,
             // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
@@ -121,7 +130,7 @@ impl<'a> Parser<'a> {
             let path = this.parse_path(PathStyle::Expr)?;
 
             if this.eat(&token::Not) {
-                let stmt_mac = this.parse_stmt_mac(lo, attrs.into(), path)?;
+                let stmt_mac = this.parse_stmt_mac(lo, attrs, path)?;
                 if this.token == token::Semi {
                     return Ok((stmt_mac, TrailingToken::Semi));
                 } else {
@@ -130,10 +139,10 @@ impl<'a> Parser<'a> {
             }
 
             let expr = if this.eat(&token::OpenDelim(Delimiter::Brace)) {
-                this.parse_struct_expr(None, path, AttrVec::new(), true)?
+                this.parse_struct_expr(None, path, true)?
             } else {
                 let hi = this.prev_token.span;
-                this.mk_expr(lo.to(hi), ExprKind::Path(None, path), AttrVec::new())
+                this.mk_expr(lo.to(hi), ExprKind::Path(None, path))
             };
 
             let expr = this.with_res(Restrictions::STMT_EXPR, |this| {
@@ -168,7 +177,7 @@ impl<'a> Parser<'a> {
             None => unreachable!(),
         };
 
-        let mac = MacCall { path, args, prior_type_ascription: self.last_type_ascription };
+        let mac = P(MacCall { path, args, prior_type_ascription: self.last_type_ascription });
 
         let kind = if (style == MacStmtStyle::Braces
             && self.token != token::Dot
@@ -179,9 +188,9 @@ impl<'a> Parser<'a> {
             StmtKind::MacCall(P(MacCallStmt { mac, style, attrs, tokens: None }))
         } else {
             // Since none of the above applied, this is an expression statement macro.
-            let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac), AttrVec::new());
+            let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
             let e = self.maybe_recover_from_bad_qpath(e)?;
-            let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?;
+            let e = self.parse_dot_or_call_expr_with(e, lo, attrs)?;
             let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
             StmtKind::Expr(e)
         };
@@ -204,13 +213,10 @@ impl<'a> Parser<'a> {
         &mut self,
         lo: Span,
         attrs: AttrWrapper,
-        msg: &str,
-        sugg: &str,
+        subdiagnostic: fn(Span) -> InvalidVariableDeclarationSub,
     ) -> PResult<'a, Stmt> {
         let stmt = self.recover_local_after_let(lo, attrs)?;
-        self.struct_span_err(lo, "invalid variable declaration")
-            .span_suggestion(lo, msg, sugg, Applicability::MachineApplicable)
-            .emit();
+        self.sess.emit_err(InvalidVariableDeclaration { span: lo, sub: subdiagnostic(lo) });
         Ok(stmt)
     }
 
@@ -223,7 +229,7 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, Stmt> {
         self.collect_tokens_trailing_token(attrs, force_collect, |this, attrs| {
             this.expect_keyword(kw::Let)?;
-            let local = this.parse_local(attrs.into())?;
+            let local = this.parse_local(attrs)?;
             let trailing = if capture_semi && this.token.kind == token::Semi {
                 TrailingToken::Semi
             } else {
@@ -235,7 +241,7 @@ impl<'a> Parser<'a> {
 
     fn recover_local_after_let(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
         self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
-            let local = this.parse_local(attrs.into())?;
+            let local = this.parse_local(attrs)?;
             // FIXME - maybe capture semicolon in recovery?
             Ok((
                 this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)),
@@ -247,6 +253,22 @@ impl<'a> Parser<'a> {
     /// Parses a local variable declaration.
     fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
         let lo = self.prev_token.span;
+
+        if self.token.is_keyword(kw::Const) && self.look_ahead(1, |t| t.is_ident()) {
+            self.struct_span_err(
+                lo.to(self.token.span),
+                "`const` and `let` are mutually exclusive",
+            )
+            .span_suggestion(
+                lo.to(self.token.span),
+                "remove `let`",
+                "const",
+                Applicability::MaybeIncorrect,
+            )
+            .emit();
+            self.bump();
+        }
+
         let (pat, colon) = self.parse_pat_before_ty(None, RecoverComma::Yes, "`let` bindings")?;
 
         let (err, ty) = if colon {
@@ -487,9 +509,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a block. Inner attributes are allowed.
-    pub(super) fn parse_inner_attrs_and_block(
-        &mut self,
-    ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
+    pub(super) fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (AttrVec, P<Block>)> {
         self.parse_block_common(self.token.span, BlockCheckMode::Default)
     }
 
@@ -498,8 +518,8 @@ impl<'a> Parser<'a> {
         &mut self,
         lo: Span,
         blk_mode: BlockCheckMode,
-    ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
-        maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
+    ) -> PResult<'a, (AttrVec, P<Block>)> {
+        maybe_whole!(self, NtBlock, |x| (AttrVec::new(), x));
 
         self.maybe_recover_unexpected_block_label();
         if !self.eat(&token::OpenDelim(Delimiter::Brace)) {
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 31b40a83e..b47f0c097 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -567,7 +567,8 @@ impl<'a> Parser<'a> {
         self.check_keyword(kw::Dyn)
             && (!self.token.uninterpolated_span().rust_2015()
                 || self.look_ahead(1, |t| {
-                    t.can_begin_bound() && !can_continue_type_after_non_fn_ident(t)
+                    (t.can_begin_bound() || t.kind == TokenKind::BinOp(token::Star))
+                        && !can_continue_type_after_non_fn_ident(t)
                 }))
     }
 
@@ -576,10 +577,18 @@ impl<'a> Parser<'a> {
     /// Note that this does *not* parse bare trait objects.
     fn parse_dyn_ty(&mut self, impl_dyn_multi: &mut bool) -> PResult<'a, TyKind> {
         self.bump(); // `dyn`
+
+        // parse dyn* types
+        let syntax = if self.eat(&TokenKind::BinOp(token::Star)) {
+            TraitObjectSyntax::DynStar
+        } else {
+            TraitObjectSyntax::Dyn
+        };
+
         // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds(None)?;
         *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
-        Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn))
+        Ok(TyKind::TraitObject(bounds, syntax))
     }
 
     /// Parses a type starting with a path.
@@ -598,11 +607,11 @@ impl<'a> Parser<'a> {
         let path = self.parse_path_inner(PathStyle::Type, ty_generics)?;
         if self.eat(&token::Not) {
             // Macro invocation in type position
-            Ok(TyKind::MacCall(MacCall {
+            Ok(TyKind::MacCall(P(MacCall {
                 path,
                 args: self.parse_mac_args()?,
                 prior_type_ascription: self.last_type_ascription,
-            }))
+            })))
         } else if allow_plus == AllowPlus::Yes && self.check_plus() {
             // `Trait1 + Trait2 + 'a`
             self.parse_remaining_bounds_path(Vec::new(), path, lo, true)
@@ -640,7 +649,13 @@ impl<'a> Parser<'a> {
         let mut bounds = Vec::new();
         let mut negative_bounds = Vec::new();
 
-        while self.can_begin_bound() || self.token.is_keyword(kw::Dyn) {
+        while self.can_begin_bound()
+            // Continue even if we find a keyword.
+            // This is necessary for error recover on, for example, `impl fn()`.
+            //
+            // The only keyword that can go after generic bounds is `where`, so stop if it's it.
+            || (self.token.is_reserved_ident() && !self.token.is_keyword(kw::Where))
+        {
             if self.token.is_keyword(kw::Dyn) {
                 // Account for `&dyn Trait + dyn Other`.
                 self.struct_span_err(self.token.span, "invalid `dyn` keyword")
@@ -804,6 +819,20 @@ impl<'a> Parser<'a> {
             let span = tilde.to(self.prev_token.span);
             self.sess.gated_spans.gate(sym::const_trait_impl, span);
             Some(span)
+        } else if self.eat_keyword(kw::Const) {
+            let span = self.prev_token.span;
+            self.sess.gated_spans.gate(sym::const_trait_impl, span);
+
+            self.struct_span_err(span, "const bounds must start with `~`")
+                .span_suggestion(
+                    span.shrink_to_lo(),
+                    "add `~`",
+                    "~",
+                    Applicability::MachineApplicable,
+                )
+                .emit();
+
+            Some(span)
         } else {
             None
         };
diff --git a/compiler/rustc_parse_format/src/lib.rs b/compiler/rustc_parse_format/src/lib.rs
index 4890fade5..a9e502016 100644
--- a/compiler/rustc_parse_format/src/lib.rs
+++ b/compiler/rustc_parse_format/src/lib.rs
@@ -9,6 +9,8 @@
     html_playground_url = "https://play.rust-lang.org/",
     test(attr(deny(warnings)))
 )]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 // We want to be able to build this crate with a stable compiler, so no
 // `#![feature]` attributes should be added.
 
@@ -165,6 +167,8 @@ pub enum Count<'a> {
     CountIsName(&'a str, InnerSpan),
     /// The count is specified by the argument at the given index.
     CountIsParam(usize),
+    /// The count is specified by a star (like in `{:.*}`) that refers to the argument at the given index.
+    CountIsStar(usize),
     /// The count is implied and cannot be explicitly specified.
     CountImplied,
 }
@@ -262,9 +266,7 @@ impl<'a> Iterator for Parser<'a> {
             }
         } else {
             if self.is_literal {
-                let start = self.to_span_index(self.cur_line_start);
-                let end = self.to_span_index(self.input.len());
-                let span = start.to(end);
+                let span = self.span(self.cur_line_start, self.input.len());
                 if self.line_spans.last() != Some(&span) {
                     self.line_spans.push(span);
                 }
@@ -382,6 +384,12 @@ impl<'a> Parser<'a> {
         InnerOffset(raw + pos + 1)
     }
 
+    fn span(&self, start_pos: usize, end_pos: usize) -> InnerSpan {
+        let start = self.to_span_index(start_pos);
+        let end = self.to_span_index(end_pos);
+        start.to(end)
+    }
+
     /// Forces consumption of the specified character. If the character is not
     /// found, an error is emitted.
     fn must_consume(&mut self, c: char) -> Option<usize> {
@@ -470,9 +478,7 @@ impl<'a> Parser<'a> {
                     return &self.input[start..pos];
                 }
                 '\n' if self.is_literal => {
-                    let start = self.to_span_index(self.cur_line_start);
-                    let end = self.to_span_index(pos);
-                    self.line_spans.push(start.to(end));
+                    self.line_spans.push(self.span(self.cur_line_start, pos));
                     self.cur_line_start = pos + 1;
                     self.cur.next();
                 }
@@ -535,6 +541,10 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn current_pos(&mut self) -> usize {
+        if let Some(&(pos, _)) = self.cur.peek() { pos } else { self.input.len() }
+    }
+
     /// Parses a format specifier at the current position, returning all of the
     /// relevant information in the `FormatSpec` struct.
     fn format(&mut self) -> FormatSpec<'a> {
@@ -588,39 +598,37 @@ impl<'a> Parser<'a> {
             // no '0' flag and '0$' as the width instead.
             if let Some(end) = self.consume_pos('$') {
                 spec.width = CountIsParam(0);
-
-                if let Some((pos, _)) = self.cur.peek().cloned() {
-                    spec.width_span = Some(self.to_span_index(pos - 2).to(self.to_span_index(pos)));
-                }
+                spec.width_span = Some(self.span(end - 1, end + 1));
                 havewidth = true;
-                spec.width_span = Some(self.to_span_index(end - 1).to(self.to_span_index(end + 1)));
             } else {
                 spec.flags |= 1 << (FlagSignAwareZeroPad as u32);
             }
         }
+
         if !havewidth {
-            let width_span_start = if let Some((pos, _)) = self.cur.peek() { *pos } else { 0 };
-            let (w, sp) = self.count(width_span_start);
-            spec.width = w;
-            spec.width_span = sp;
+            let start = self.current_pos();
+            spec.width = self.count(start);
+            if spec.width != CountImplied {
+                let end = self.current_pos();
+                spec.width_span = Some(self.span(start, end));
+            }
         }
 
         if let Some(start) = self.consume_pos('.') {
-            if let Some(end) = self.consume_pos('*') {
+            if self.consume('*') {
                 // Resolve `CountIsNextParam`.
                 // We can do this immediately as `position` is resolved later.
                 let i = self.curarg;
                 self.curarg += 1;
-                spec.precision = CountIsParam(i);
-                spec.precision_span =
-                    Some(self.to_span_index(start).to(self.to_span_index(end + 1)));
+                spec.precision = CountIsStar(i);
             } else {
-                let (p, sp) = self.count(start);
-                spec.precision = p;
-                spec.precision_span = sp;
+                spec.precision = self.count(start + 1);
             }
+            let end = self.current_pos();
+            spec.precision_span = Some(self.span(start, end));
         }
-        let ty_span_start = self.cur.peek().map(|(pos, _)| *pos);
+
+        let ty_span_start = self.current_pos();
         // Optional radix followed by the actual format specifier
         if self.consume('x') {
             if self.consume('?') {
@@ -640,11 +648,9 @@ impl<'a> Parser<'a> {
             spec.ty = "?";
         } else {
             spec.ty = self.word();
-            let ty_span_end = self.cur.peek().map(|(pos, _)| *pos);
             if !spec.ty.is_empty() {
-                spec.ty_span = ty_span_start
-                    .and_then(|s| ty_span_end.map(|e| (s, e)))
-                    .map(|(start, end)| self.to_span_index(start).to(self.to_span_index(end)));
+                let ty_span_end = self.current_pos();
+                spec.ty_span = Some(self.span(ty_span_start, ty_span_end));
             }
         }
         spec
@@ -668,13 +674,11 @@ impl<'a> Parser<'a> {
             return spec;
         }
 
-        let ty_span_start = self.cur.peek().map(|(pos, _)| *pos);
+        let ty_span_start = self.current_pos();
         spec.ty = self.word();
-        let ty_span_end = self.cur.peek().map(|(pos, _)| *pos);
         if !spec.ty.is_empty() {
-            spec.ty_span = ty_span_start
-                .and_then(|s| ty_span_end.map(|e| (s, e)))
-                .map(|(start, end)| self.to_span_index(start).to(self.to_span_index(end)));
+            let ty_span_end = self.current_pos();
+            spec.ty_span = Some(self.span(ty_span_start, ty_span_end));
         }
 
         spec
@@ -683,26 +687,21 @@ impl<'a> Parser<'a> {
     /// Parses a `Count` parameter at the current position. This does not check
     /// for 'CountIsNextParam' because that is only used in precision, not
     /// width.
-    fn count(&mut self, start: usize) -> (Count<'a>, Option<InnerSpan>) {
+    fn count(&mut self, start: usize) -> Count<'a> {
         if let Some(i) = self.integer() {
-            if let Some(end) = self.consume_pos('$') {
-                let span = self.to_span_index(start).to(self.to_span_index(end + 1));
-                (CountIsParam(i), Some(span))
-            } else {
-                (CountIs(i), None)
-            }
+            if self.consume('$') { CountIsParam(i) } else { CountIs(i) }
         } else {
             let tmp = self.cur.clone();
             let word = self.word();
             if word.is_empty() {
                 self.cur = tmp;
-                (CountImplied, None)
+                CountImplied
             } else if let Some(end) = self.consume_pos('$') {
-                let span = self.to_span_index(start + 1).to(self.to_span_index(end));
-                (CountIsName(word, span), None)
+                let name_span = self.span(start, end);
+                CountIsName(word, name_span)
             } else {
                 self.cur = tmp;
-                (CountImplied, None)
+                CountImplied
             }
         }
     }
@@ -735,7 +734,7 @@ impl<'a> Parser<'a> {
                 "invalid argument name `_`",
                 "invalid argument name",
                 "argument name cannot be a single underscore",
-                self.to_span_index(start).to(self.to_span_index(end)),
+                self.span(start, end),
             );
         }
         word
diff --git a/compiler/rustc_parse_format/src/tests.rs b/compiler/rustc_parse_format/src/tests.rs
index 578530696..2f8c229c6 100644
--- a/compiler/rustc_parse_format/src/tests.rs
+++ b/compiler/rustc_parse_format/src/tests.rs
@@ -1,5 +1,6 @@
 use super::*;
 
+#[track_caller]
 fn same(fmt: &'static str, p: &[Piece<'static>]) {
     let parser = Parser::new(fmt, None, None, false, ParseMode::Format);
     assert_eq!(parser.collect::<Vec<Piece<'static>>>(), p);
@@ -190,9 +191,9 @@ fn format_counts() {
                 align: AlignUnknown,
                 flags: 0,
                 precision: CountImplied,
-                width: CountIs(10),
                 precision_span: None,
-                width_span: None,
+                width: CountIs(10),
+                width_span: Some(InnerSpan { start: 3, end: 5 }),
                 ty: "x",
                 ty_span: None,
             },
@@ -208,9 +209,9 @@ fn format_counts() {
                 align: AlignUnknown,
                 flags: 0,
                 precision: CountIs(10),
+                precision_span: Some(InnerSpan { start: 6, end: 9 }),
                 width: CountIsParam(10),
-                precision_span: None,
-                width_span: Some(InnerSpan::new(3, 6)),
+                width_span: Some(InnerSpan { start: 3, end: 6 }),
                 ty: "x",
                 ty_span: None,
             },
@@ -226,9 +227,9 @@ fn format_counts() {
                 align: AlignUnknown,
                 flags: 0,
                 precision: CountIs(10),
+                precision_span: Some(InnerSpan { start: 6, end: 9 }),
                 width: CountIsParam(0),
-                precision_span: None,
-                width_span: Some(InnerSpan::new(4, 6)),
+                width_span: Some(InnerSpan { start: 4, end: 6 }),
                 ty: "x",
                 ty_span: None,
             },
@@ -243,9 +244,9 @@ fn format_counts() {
                 fill: None,
                 align: AlignUnknown,
                 flags: 0,
-                precision: CountIsParam(0),
+                precision: CountIsStar(0),
+                precision_span: Some(InnerSpan { start: 3, end: 5 }),
                 width: CountImplied,
-                precision_span: Some(InnerSpan::new(3, 5)),
                 width_span: None,
                 ty: "x",
                 ty_span: None,
@@ -279,15 +280,33 @@ fn format_counts() {
                 fill: None,
                 align: AlignUnknown,
                 flags: 0,
-                precision: CountIsName("b", InnerSpan::new(6, 7)),
-                width: CountIsName("a", InnerSpan::new(4, 4)),
-                precision_span: None,
-                width_span: None,
+                precision: CountIsName("b", InnerSpan { start: 6, end: 7 }),
+                precision_span: Some(InnerSpan { start: 5, end: 8 }),
+                width: CountIsName("a", InnerSpan { start: 3, end: 4 }),
+                width_span: Some(InnerSpan { start: 3, end: 5 }),
                 ty: "?",
                 ty_span: None,
             },
         })],
     );
+    same(
+        "{:.4}",
+        &[NextArgument(Argument {
+            position: ArgumentImplicitlyIs(0),
+            position_span: InnerSpan { start: 2, end: 2 },
+            format: FormatSpec {
+                fill: None,
+                align: AlignUnknown,
+                flags: 0,
+                precision: CountIs(4),
+                precision_span: Some(InnerSpan { start: 3, end: 5 }),
+                width: CountImplied,
+                width_span: None,
+                ty: "",
+                ty_span: None,
+            },
+        })],
+    )
 }
 #[test]
 fn format_flags() {