Rollup of 6 pull requests

compiler/rustc_ast/src/mut_visit.rs

@@ -152,6 +152,12 @@ pub trait MutVisitor: Sized {
         noop_visit_expr(e, self);
     }
 
+    /// This method is a hack to workaround unstable of `stmt_expr_attributes`.
+    /// It can be removed once that feature is stabilized.
+    fn visit_method_receiver_expr(&mut self, ex: &mut P<Expr>) {
+        self.visit_expr(ex)
+    }
+
     fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
         noop_filter_map_expr(e, self)
     }
@@ -1301,7 +1307,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             vis.visit_ident(ident);
             vis.visit_id(id);
             visit_opt(args, |args| vis.visit_generic_args(args));
-            vis.visit_expr(receiver);
+            vis.visit_method_receiver_expr(receiver);
             visit_exprs(exprs, vis);
             vis.visit_span(span);
         }
@@ -1589,3 +1595,9 @@ impl DummyAstNode for Crate {
         }
     }
 }
+
+impl<N: DummyAstNode, T: DummyAstNode> DummyAstNode for crate::ast_traits::AstNodeWrapper<N, T> {
+    fn dummy() -> Self {
+        crate::ast_traits::AstNodeWrapper::new(N::dummy(), T::dummy())
+    }
+}

compiler/rustc_ast/src/visit.rs

@@ -140,6 +140,11 @@ pub trait Visitor<'ast>: Sized {
     fn visit_expr(&mut self, ex: &'ast Expr) {
         walk_expr(self, ex)
     }
+    /// This method is a hack to workaround unstable of `stmt_expr_attributes`.
+    /// It can be removed once that feature is stabilized.
+    fn visit_method_receiver_expr(&mut self, ex: &'ast Expr) {
+        self.visit_expr(ex)
+    }
     fn visit_expr_post(&mut self, _ex: &'ast Expr) {}
     fn visit_ty(&mut self, t: &'ast Ty) {
         walk_ty(self, t)

compiler/rustc_builtin_macros/src/cfg_eval.rs

@@ -210,8 +210,15 @@ impl CfgEval<'_, '_> {
 }
 
 impl MutVisitor for CfgEval<'_, '_> {
+    #[instrument(level = "trace", skip(self))]
     fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
-        self.cfg.configure_expr(expr);
+        self.cfg.configure_expr(expr, false);
+        mut_visit::noop_visit_expr(expr, self);
+    }
+
+    #[instrument(level = "trace", skip(self))]
+    fn visit_method_receiver_expr(&mut self, expr: &mut P<ast::Expr>) {
+        self.cfg.configure_expr(expr, true);
         mut_visit::noop_visit_expr(expr, self);
     }
 

compiler/rustc_errors/src/diagnostic.rs

@@ -690,6 +690,24 @@ impl Diagnostic {
         msg: impl Into<SubdiagnosticMessage>,
         suggestions: impl Iterator<Item = String>,
         applicability: Applicability,
+    ) -> &mut Self {
+        self.span_suggestions_with_style(
+            sp,
+            msg,
+            suggestions,
+            applicability,
+            SuggestionStyle::ShowCode,
+        )
+    }
+
+    /// [`Diagnostic::span_suggestions()`] but you can set the [`SuggestionStyle`].
+    pub fn span_suggestions_with_style(
+        &mut self,
+        sp: Span,
+        msg: impl Into<SubdiagnosticMessage>,
+        suggestions: impl Iterator<Item = String>,
+        applicability: Applicability,
+        style: SuggestionStyle,
     ) -> &mut Self {
         let mut suggestions: Vec<_> = suggestions.collect();
         suggestions.sort();
@@ -706,14 +724,15 @@ impl Diagnostic {
         self.push_suggestion(CodeSuggestion {
             substitutions,
             msg: self.subdiagnostic_message_to_diagnostic_message(msg),
-            style: SuggestionStyle::ShowCode,
+            style,
             applicability,
         });
         self
     }
 
-    /// Prints out a message with multiple suggested edits of the code.
-    /// See also [`Diagnostic::span_suggestion()`].
+    /// Prints out a message with multiple suggested edits of the code, where each edit consists of
+    /// multiple parts.
+    /// See also [`Diagnostic::multipart_suggestion()`].
     pub fn multipart_suggestions(
         &mut self,
         msg: impl Into<SubdiagnosticMessage>,
@@ -745,6 +764,7 @@ impl Diagnostic {
         });
         self
     }
+
     /// Prints out a message with a suggested edit of the code. If the suggestion is presented
     /// inline, it will only show the message and not the suggestion.
     ///

compiler/rustc_expand/src/config.rs

@@ -469,6 +469,7 @@ impl<'a> StripUnconfigured<'a> {
     }
 
     /// If attributes are not allowed on expressions, emit an error for `attr`
+    #[instrument(level = "trace", skip(self))]
     pub(crate) fn maybe_emit_expr_attr_err(&self, attr: &Attribute) {
         if !self.features.map_or(true, |features| features.stmt_expr_attributes) {
             let mut err = feature_err(
@@ -486,9 +487,12 @@ impl<'a> StripUnconfigured<'a> {
         }
     }
 
-    pub fn configure_expr(&self, expr: &mut P<ast::Expr>) {
-        for attr in expr.attrs.iter() {
-            self.maybe_emit_expr_attr_err(attr);
+    #[instrument(level = "trace", skip(self))]
+    pub fn configure_expr(&self, expr: &mut P<ast::Expr>, method_receiver: bool) {
+        if !method_receiver {
+            for attr in expr.attrs.iter() {
+                self.maybe_emit_expr_attr_err(attr);
+            }
         }
 
         // If an expr is valid to cfg away it will have been removed by the

compiler/rustc_expand/src/expand.rs

@@ -50,20 +50,23 @@ macro_rules! ast_fragments {
         /// Can also serve as an input and intermediate result for macro expansion operations.
         pub enum AstFragment {
             OptExpr(Option<P<ast::Expr>>),
+            MethodReceiverExpr(P<ast::Expr>),
             $($Kind($AstTy),)*
         }
 
         /// "Discriminant" of an AST fragment.
         #[derive(Copy, Clone, PartialEq, Eq)]
         pub enum AstFragmentKind {
             OptExpr,
+            MethodReceiverExpr,
             $($Kind,)*
         }
 
         impl AstFragmentKind {
             pub fn name(self) -> &'static str {
                 match self {
                     AstFragmentKind::OptExpr => "expression",
+                    AstFragmentKind::MethodReceiverExpr => "expression",
                     $(AstFragmentKind::$Kind => $kind_name,)*
                 }
             }
@@ -72,6 +75,8 @@ macro_rules! ast_fragments {
                 match self {
                     AstFragmentKind::OptExpr =>
                         result.make_expr().map(Some).map(AstFragment::OptExpr),
+                    AstFragmentKind::MethodReceiverExpr =>
+                        result.make_expr().map(AstFragment::MethodReceiverExpr),
                     $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
                 }
             }
@@ -98,6 +103,13 @@ macro_rules! ast_fragments {
                 }
             }
 
+            pub fn make_method_receiver_expr(self) -> P<ast::Expr> {
+                match self {
+                    AstFragment::MethodReceiverExpr(expr) => expr,
+                    _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
+                }
+            }
+
             $(pub fn $make_ast(self) -> $AstTy {
                 match self {
                     AstFragment::$Kind(ast) => ast,
@@ -120,6 +132,7 @@ macro_rules! ast_fragments {
                             }
                         });
                     }
+                    AstFragment::MethodReceiverExpr(expr) => vis.visit_method_receiver_expr(expr),
                     $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
                     $($(AstFragment::$Kind(ast) =>
                         ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
@@ -130,6 +143,7 @@ macro_rules! ast_fragments {
                 match *self {
                     AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
                     AstFragment::OptExpr(None) => {}
+                    AstFragment::MethodReceiverExpr(ref expr) => visitor.visit_method_receiver_expr(expr),
                     $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
                     $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
                         visitor.$visit_ast_elt(ast_elt, $($args)*);
@@ -222,6 +236,7 @@ impl AstFragmentKind {
         match self {
             AstFragmentKind::OptExpr
             | AstFragmentKind::Expr
+            | AstFragmentKind::MethodReceiverExpr
             | AstFragmentKind::Stmts
             | AstFragmentKind::Ty
             | AstFragmentKind::Pat => SupportsMacroExpansion::Yes { supports_inner_attrs: false },
@@ -285,6 +300,9 @@ impl AstFragmentKind {
             AstFragmentKind::Expr => AstFragment::Expr(
                 items.next().expect("expected exactly one expression").expect_expr(),
             ),
+            AstFragmentKind::MethodReceiverExpr => AstFragment::MethodReceiverExpr(
+                items.next().expect("expected exactly one expression").expect_expr(),
+            ),
             AstFragmentKind::OptExpr => {
                 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
             }
@@ -893,6 +911,7 @@ pub fn parse_ast_fragment<'a>(
             AstFragment::Stmts(stmts)
         }
         AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
+        AstFragmentKind::MethodReceiverExpr => AstFragment::MethodReceiverExpr(this.parse_expr()?),
         AstFragmentKind::OptExpr => {
             if this.token != token::Eof {
                 AstFragment::OptExpr(Some(this.parse_expr()?))
@@ -1477,6 +1496,42 @@ impl InvocationCollectorNode for AstNodeWrapper<P<ast::Expr>, OptExprTag> {
     }
 }
 
+/// This struct is a hack to workaround unstable of `stmt_expr_attributes`.
+/// It can be removed once that feature is stabilized.
+struct MethodReceiverTag;
+impl DummyAstNode for MethodReceiverTag {
+    fn dummy() -> MethodReceiverTag {
+        MethodReceiverTag
+    }
+}
+impl InvocationCollectorNode for AstNodeWrapper<P<ast::Expr>, MethodReceiverTag> {
+    type OutputTy = Self;
+    type AttrsTy = ast::AttrVec;
+    const KIND: AstFragmentKind = AstFragmentKind::MethodReceiverExpr;
+    fn descr() -> &'static str {
+        "an expression"
+    }
+    fn to_annotatable(self) -> Annotatable {
+        Annotatable::Expr(self.wrapped)
+    }
+    fn fragment_to_output(fragment: AstFragment) -> Self::OutputTy {
+        AstNodeWrapper::new(fragment.make_method_receiver_expr(), MethodReceiverTag)
+    }
+    fn noop_visit<V: MutVisitor>(&mut self, visitor: &mut V) {
+        noop_visit_expr(&mut self.wrapped, visitor)
+    }
+    fn is_mac_call(&self) -> bool {
+        matches!(self.wrapped.kind, ast::ExprKind::MacCall(..))
+    }
+    fn take_mac_call(self) -> (P<ast::MacCall>, Self::AttrsTy, AddSemicolon) {
+        let node = self.wrapped.into_inner();
+        match node.kind {
+            ExprKind::MacCall(mac) => (mac, node.attrs, AddSemicolon::No),
+            _ => unreachable!(),
+        }
+    }
+}
+
 struct InvocationCollector<'a, 'b> {
     cx: &'a mut ExtCtxt<'b>,
     invocations: Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>,
@@ -1840,6 +1895,14 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
         self.visit_node(node)
     }
 
+    fn visit_method_receiver_expr(&mut self, node: &mut P<ast::Expr>) {
+        visit_clobber(node, |node| {
+            let mut wrapper = AstNodeWrapper::new(node, MethodReceiverTag);
+            self.visit_node(&mut wrapper);
+            wrapper.wrapped
+        })
+    }
+
     fn filter_map_expr(&mut self, node: P<ast::Expr>) -> Option<P<ast::Expr>> {
         self.flat_map_node(AstNodeWrapper::new(node, OptExprTag))
     }

compiler/rustc_expand/src/placeholders.rs

@@ -55,6 +55,7 @@ pub fn placeholder(
         }),
         AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
         AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
+        AstFragmentKind::MethodReceiverExpr => AstFragment::MethodReceiverExpr(expr_placeholder()),
         AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
             id,
             span,
@@ -296,6 +297,13 @@ impl MutVisitor for PlaceholderExpander {
         }
     }
 
+    fn visit_method_receiver_expr(&mut self, expr: &mut P<ast::Expr>) {
+        match expr.kind {
+            ast::ExprKind::MacCall(_) => *expr = self.remove(expr.id).make_method_receiver_expr(),
+            _ => noop_visit_expr(expr, self),
+        }
+    }
+
     fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
         match expr.kind {
             ast::ExprKind::MacCall(_) => self.remove(expr.id).make_opt_expr(),