Auto merge of #3479 - rust-lang:rustup-2024-04-17, r=RalfJung

Automatic Rustup

8 files changed, 80 insertions, 40 deletions

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 7038b8bbe47..64f766543a7 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -279,7 +279,7 @@ impl<'a> Parser<'a> {
             TokenKind::Colon,
             TokenKind::Comma,
             TokenKind::Semi,
-            TokenKind::ModSep,
+            TokenKind::PathSep,
             TokenKind::OpenDelim(Delimiter::Brace),
             TokenKind::OpenDelim(Delimiter::Parenthesis),
             TokenKind::CloseDelim(Delimiter::Brace),
@@ -1169,7 +1169,7 @@ impl<'a> Parser<'a> {
             return;
         }
 
-        if token::ModSep == self.token.kind && segment.args.is_none() {
+        if token::PathSep == self.token.kind && segment.args.is_none() {
             let snapshot = self.create_snapshot_for_diagnostic();
             self.bump();
             let lo = self.token.span;
@@ -1420,7 +1420,7 @@ impl<'a> Parser<'a> {
                             [(token::Lt, 1), (token::Gt, -1), (token::BinOp(token::Shr), -2)];
                         self.consume_tts(1, &modifiers);
 
-                        if !&[token::OpenDelim(Delimiter::Parenthesis), token::ModSep]
+                        if !&[token::OpenDelim(Delimiter::Parenthesis), token::PathSep]
                             .contains(&self.token.kind)
                         {
                             // We don't have `foo< bar >(` or `foo< bar >::`, so we rewind the
@@ -1428,7 +1428,7 @@ impl<'a> Parser<'a> {
                             self.restore_snapshot(snapshot);
                         }
                     }
-                    return if token::ModSep == self.token.kind {
+                    return if token::PathSep == self.token.kind {
                         // We have some certainty that this was a bad turbofish at this point.
                         // `foo< bar >::`
                         if let ExprKind::Binary(o, ..) = inner_op.kind
@@ -1784,7 +1784,7 @@ impl<'a> Parser<'a> {
         }
 
         // Do not add `::` to expected tokens.
-        if self.token == token::ModSep {
+        if self.token == token::PathSep {
             if let Some(ty) = base.to_ty() {
                 return self.maybe_recover_from_bad_qpath_stage_2(ty.span, ty);
             }
@@ -1799,7 +1799,7 @@ impl<'a> Parser<'a> {
         ty_span: Span,
         ty: P<Ty>,
     ) -> PResult<'a, P<T>> {
-        self.expect(&token::ModSep)?;
+        self.expect(&token::PathSep)?;
 
         let mut path = ast::Path { segments: ThinVec::new(), span: DUMMY_SP, tokens: None };
         self.parse_path_segments(&mut path.segments, T::PATH_STYLE, None)?;
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index fde16ac957d..93a15c938ec 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -62,7 +62,7 @@ impl<'a> Parser<'a> {
                 let snapshot = self.create_snapshot_for_diagnostic();
                 match self.parse_ty() {
                     Ok(p) => {
-                        if let TyKind::ImplTrait(_, bounds) = &p.kind {
+                        if let TyKind::ImplTrait(_, bounds, None) = &p.kind {
                             let span = impl_span.to(self.token.span.shrink_to_lo());
                             let mut err = self.dcx().struct_span_err(
                                 span,
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index d54eb8dc4c9..8ae809f566b 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -358,12 +358,12 @@ impl<'a> Parser<'a> {
     fn is_reuse_path_item(&mut self) -> bool {
         // no: `reuse ::path` for compatibility reasons with macro invocations
         self.token.is_keyword(kw::Reuse)
-            && self.look_ahead(1, |t| t.is_path_start() && t.kind != token::ModSep)
+            && self.look_ahead(1, |t| t.is_path_start() && t.kind != token::PathSep)
     }
 
     /// Are we sure this could not possibly be a macro invocation?
     fn isnt_macro_invocation(&mut self) -> bool {
-        self.check_ident() && self.look_ahead(1, |t| *t != token::Not && *t != token::ModSep)
+        self.check_ident() && self.look_ahead(1, |t| *t != token::Not && *t != token::PathSep)
     }
 
     /// Recover on encountering a struct or method definition where the user
@@ -625,7 +625,7 @@ impl<'a> Parser<'a> {
                     // This notably includes paths passed through `ty` macro fragments (#46438).
                     TyKind::Path(None, path) => path,
                     other => {
-                        if let TyKind::ImplTrait(_, bounds) = other
+                        if let TyKind::ImplTrait(_, bounds, None) = other
                             && let [bound] = bounds.as_slice()
                         {
                             // Suggest removing extra `impl` keyword:
@@ -1020,7 +1020,7 @@ impl<'a> Parser<'a> {
         {
             // `use *;` or `use ::*;` or `use {...};` or `use ::{...};`
             let mod_sep_ctxt = self.token.span.ctxt();
-            if self.eat(&token::ModSep) {
+            if self.eat(&token::PathSep) {
                 prefix
                     .segments
                     .push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
@@ -1031,7 +1031,7 @@ impl<'a> Parser<'a> {
             // `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;`
             prefix = self.parse_path(PathStyle::Mod)?;
 
-            if self.eat(&token::ModSep) {
+            if self.eat(&token::PathSep) {
                 self.parse_use_tree_glob_or_nested()?
             } else {
                 // Recover from using a colon as path separator.
@@ -1063,7 +1063,7 @@ impl<'a> Parser<'a> {
     /// Parses a `UseTreeKind::Nested(list)`.
     ///
     /// ```text
-    /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
+    /// USE_TREE_LIST = ∅ | (USE_TREE `,`)* USE_TREE [`,`]
     /// ```
     fn parse_use_tree_list(&mut self) -> PResult<'a, ThinVec<(UseTree, ast::NodeId)>> {
         self.parse_delim_comma_seq(Delimiter::Brace, |p| {
@@ -1968,11 +1968,8 @@ impl<'a> Parser<'a> {
         } else if matches!(is_raw, IdentIsRaw::No) && ident.is_reserved() {
             let snapshot = self.create_snapshot_for_diagnostic();
             let err = if self.check_fn_front_matter(false, Case::Sensitive) {
-                let inherited_vis = Visibility {
-                    span: rustc_span::DUMMY_SP,
-                    kind: VisibilityKind::Inherited,
-                    tokens: None,
-                };
+                let inherited_vis =
+                    Visibility { span: DUMMY_SP, kind: VisibilityKind::Inherited, tokens: None };
                 // We use `parse_fn` to get a span for the function
                 let fn_parse_mode = FnParseMode { req_name: |_| true, req_body: true };
                 match self.parse_fn(
@@ -2752,7 +2749,7 @@ impl<'a> Parser<'a> {
         // Is `self` `n` tokens ahead?
         let is_isolated_self = |this: &Self, n| {
             this.is_keyword_ahead(n, &[kw::SelfLower])
-                && this.look_ahead(n + 1, |t| t != &token::ModSep)
+                && this.look_ahead(n + 1, |t| t != &token::PathSep)
         };
         // Is `mut self` `n` tokens ahead?
         let is_isolated_mut_self =
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 09bc00403f3..a4a9ba9d229 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -109,7 +109,7 @@ macro_rules! maybe_recover_from_interpolated_ty_qpath {
     ($self: expr, $allow_qpath_recovery: expr) => {
         if $allow_qpath_recovery
             && $self.may_recover()
-            && $self.look_ahead(1, |t| t == &token::ModSep)
+            && $self.look_ahead(1, |t| t == &token::PathSep)
             && let token::Interpolated(nt) = &$self.token.kind
             && let token::NtTy(ty) = &nt.0
         {
@@ -1532,7 +1532,7 @@ impl<'a> Parser<'a> {
 
     /// `::{` or `::*`
     fn is_import_coupler(&mut self) -> bool {
-        self.check(&token::ModSep)
+        self.check(&token::PathSep)
             && self.look_ahead(1, |t| {
                 *t == token::OpenDelim(Delimiter::Brace) || *t == token::BinOp(token::Star)
             })
diff --git a/compiler/rustc_parse/src/parser/nonterminal.rs b/compiler/rustc_parse/src/parser/nonterminal.rs
index 36a00df7b44..73b17353ac9 100644
--- a/compiler/rustc_parse/src/parser/nonterminal.rs
+++ b/compiler/rustc_parse/src/parser/nonterminal.rs
@@ -62,7 +62,7 @@ impl<'a> Parser<'a> {
                 _ => false,
             },
             NonterminalKind::Path | NonterminalKind::Meta => match &token.kind {
-                token::ModSep | token::Ident(..) => true,
+                token::PathSep | token::Ident(..) => true,
                 token::Interpolated(nt) => may_be_ident(&nt.0),
                 _ => false,
             },
@@ -76,7 +76,7 @@ impl<'a> Parser<'a> {
                 token::Literal(_) |                         // literal
                 token::DotDot |                             // range pattern (future compat)
                 token::DotDotDot |                          // range pattern (future compat)
-                token::ModSep |                             // path
+                token::PathSep |                             // path
                 token::Lt |                                 // path (UFCS constant)
                 token::BinOp(token::Shl) => true,           // path (double UFCS)
                 // leading vert `|` or-pattern
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 59e0cd92c4c..dd1ecf9b7c1 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -1016,7 +1016,7 @@ impl<'a> Parser<'a> {
         && self.look_ahead(1, |t| !matches!(t.kind, token::OpenDelim(Delimiter::Parenthesis) // A tuple struct pattern.
             | token::OpenDelim(Delimiter::Brace) // A struct pattern.
             | token::DotDotDot | token::DotDotEq | token::DotDot // A range pattern.
-            | token::ModSep // A tuple / struct variant pattern.
+            | token::PathSep // A tuple / struct variant pattern.
             | token::Not)) // A macro expanding to a pattern.
     }
 
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 608cdd945ff..0f410772dd9 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -96,7 +96,7 @@ impl<'a> Parser<'a> {
         }
 
         if !self.recover_colon_before_qpath_proj() {
-            self.expect(&token::ModSep)?;
+            self.expect(&token::PathSep)?;
         }
 
         let qself = P(QSelf { ty, path_span, position: path.segments.len() });
@@ -200,7 +200,7 @@ impl<'a> Parser<'a> {
         let lo = self.token.span;
         let mut segments = ThinVec::new();
         let mod_sep_ctxt = self.token.span.ctxt();
-        if self.eat(&token::ModSep) {
+        if self.eat(&token::PathSep) {
             segments.push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
         }
         self.parse_path_segments(&mut segments, style, ty_generics)?;
@@ -232,11 +232,11 @@ impl<'a> Parser<'a> {
                 // `PathStyle::Expr` is only provided at the root invocation and never in
                 // `parse_path_segment` to recurse and therefore can be checked to maintain
                 // this invariant.
-                self.check_trailing_angle_brackets(&segment, &[&token::ModSep]);
+                self.check_trailing_angle_brackets(&segment, &[&token::PathSep]);
             }
             segments.push(segment);
 
-            if self.is_import_coupler() || !self.eat(&token::ModSep) {
+            if self.is_import_coupler() || !self.eat(&token::PathSep) {
                 if style == PathStyle::Expr
                     && self.may_recover()
                     && self.token == token::Colon
@@ -291,7 +291,7 @@ impl<'a> Parser<'a> {
         Ok(
             if style == PathStyle::Type && check_args_start(self)
                 || style != PathStyle::Mod
-                    && self.check(&token::ModSep)
+                    && self.check(&token::PathSep)
                     && self.look_ahead(1, |t| is_args_start(t))
             {
                 // We use `style == PathStyle::Expr` to check if this is in a recursion or not. If
@@ -303,7 +303,7 @@ impl<'a> Parser<'a> {
                 }
 
                 // Generic arguments are found - `<`, `(`, `::<` or `::(`.
-                self.eat(&token::ModSep);
+                self.eat(&token::PathSep);
                 let lo = self.token.span;
                 let args = if self.eat_lt() {
                     // `<'a, T, A = U>`
@@ -379,7 +379,7 @@ impl<'a> Parser<'a> {
                     let token_before_parsing = self.token.clone();
                     let mut snapshot = None;
                     if self.may_recover()
-                        && prev_token_before_parsing.kind == token::ModSep
+                        && prev_token_before_parsing.kind == token::PathSep
                         && (style == PathStyle::Expr && self.token.can_begin_expr()
                             || style == PathStyle::Pat && self.token.can_begin_pattern())
                     {
@@ -388,7 +388,7 @@ impl<'a> Parser<'a> {
 
                     let (inputs, _) = match self.parse_paren_comma_seq(|p| p.parse_ty()) {
                         Ok(output) => output,
-                        Err(mut error) if prev_token_before_parsing.kind == token::ModSep => {
+                        Err(mut error) if prev_token_before_parsing.kind == token::PathSep => {
                             error.span_label(
                                 prev_token_before_parsing.span.to(token_before_parsing.span),
                                 "while parsing this parenthesized list of type arguments starting here",
@@ -470,7 +470,7 @@ impl<'a> Parser<'a> {
             }
         }
 
-        if let token::ModSep | token::RArrow = self.token.kind {
+        if let token::PathSep | token::RArrow = self.token.kind {
             return;
         }
 
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 1cea32cb90f..7096b201f84 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -1,4 +1,4 @@
-use super::{Parser, PathStyle, TokenType, Trailing};
+use super::{Parser, PathStyle, SeqSep, TokenType, Trailing};
 
 use crate::errors::{
     self, DynAfterMut, ExpectedFnPathFoundFnKeyword, ExpectedMutOrConstInRawPointerType,
@@ -14,7 +14,7 @@ use rustc_ast::util::case::Case;
 use rustc_ast::{
     self as ast, BareFnTy, BoundAsyncness, BoundConstness, BoundPolarity, FnRetTy, GenericBound,
     GenericBounds, GenericParam, Generics, Lifetime, MacCall, MutTy, Mutability, PolyTraitRef,
-    TraitBoundModifiers, TraitObjectSyntax, Ty, TyKind, DUMMY_NODE_ID,
+    PreciseCapturingArg, TraitBoundModifiers, TraitObjectSyntax, Ty, TyKind, DUMMY_NODE_ID,
 };
 use rustc_errors::{Applicability, PResult};
 use rustc_span::symbol::{kw, sym, Ident};
@@ -82,7 +82,7 @@ enum AllowCVariadic {
 /// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes
 /// that `IDENT` is not the ident of a fn trait.
 fn can_continue_type_after_non_fn_ident(t: &Token) -> bool {
-    t == &token::ModSep || t == &token::Lt || t == &token::BinOp(token::Shl)
+    t == &token::PathSep || t == &token::Lt || t == &token::BinOp(token::Shl)
 }
 
 fn can_begin_dyn_bound_in_edition_2015(t: &Token) -> bool {
@@ -316,7 +316,7 @@ impl<'a> Parser<'a> {
                             TyKind::TraitObject(bounds, TraitObjectSyntax::Dyn)
                         }
                         (TyKind::TraitObject(bounds, _), kw::Impl) => {
-                            TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)
+                            TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds, None)
                         }
                         _ => return Err(err),
                     };
@@ -655,7 +655,6 @@ impl<'a> Parser<'a> {
 
     /// Parses an `impl B0 + ... + Bn` type.
     fn parse_impl_ty(&mut self, impl_dyn_multi: &mut bool) -> PResult<'a, TyKind> {
-        // Always parse bounds greedily for better error recovery.
         if self.token.is_lifetime() {
             self.look_ahead(1, |t| {
                 if let token::Ident(sym, _) = t.kind {
@@ -669,9 +668,53 @@ impl<'a> Parser<'a> {
                 }
             })
         }
+
+        // parse precise captures, if any. This is `use<'lt, 'lt, P, P>`; a list of
+        // lifetimes and ident params (including SelfUpper). These are validated later
+        // for order, duplication, and whether they actually reference params.
+        let precise_capturing = if self.eat_keyword(kw::Use) {
+            let use_span = self.prev_token.span;
+            self.psess.gated_spans.gate(sym::precise_capturing, use_span);
+            let args = self.parse_precise_capturing_args()?;
+            Some(P((args, use_span)))
+        } else {
+            None
+        };
+
+        // Always parse bounds greedily for better error recovery.
         let bounds = self.parse_generic_bounds()?;
+
         *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus);
-        Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds))
+
+        Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds, precise_capturing))
+    }
+
+    fn parse_precise_capturing_args(&mut self) -> PResult<'a, ThinVec<PreciseCapturingArg>> {
+        Ok(self
+            .parse_unspanned_seq(
+                &TokenKind::Lt,
+                &TokenKind::Gt,
+                SeqSep::trailing_allowed(token::Comma),
+                |self_| {
+                    if self_.check_keyword(kw::SelfUpper) {
+                        self_.bump();
+                        Ok(PreciseCapturingArg::Arg(
+                            ast::Path::from_ident(self_.prev_token.ident().unwrap().0),
+                            DUMMY_NODE_ID,
+                        ))
+                    } else if self_.check_ident() {
+                        Ok(PreciseCapturingArg::Arg(
+                            ast::Path::from_ident(self_.parse_ident()?),
+                            DUMMY_NODE_ID,
+                        ))
+                    } else if self_.check_lifetime() {
+                        Ok(PreciseCapturingArg::Lifetime(self_.expect_lifetime()))
+                    } else {
+                        self_.unexpected_any()
+                    }
+                },
+            )?
+            .0)
     }
 
     /// Is a `dyn B0 + ... + Bn` type allowed here?
@@ -957,7 +1000,7 @@ impl<'a> Parser<'a> {
                             Applicability::MaybeIncorrect,
                         )
                     }
-                    TyKind::ImplTrait(_, bounds)
+                    TyKind::ImplTrait(_, bounds, None)
                         if let [GenericBound::Trait(tr, ..), ..] = bounds.as_slice() =>
                     {
                         (