Rollup of 6 pull requests

compiler/rustc_ast_passes/messages.ftl

@@ -269,6 +269,9 @@ ast_passes_unsafe_negative_impl = negative impls cannot be unsafe
     .negative = negative because of this
     .unsafe = unsafe because of this
 
+ast_passes_unsafe_static =
+    static items cannot be declared with `unsafe` safety qualifier outside of `extern` block
+
 ast_passes_visibility_not_permitted =
     visibility qualifiers are not permitted here
     .enum_variant = enum variants and their fields always share the visibility of the enum they are in

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -438,6 +438,11 @@ impl<'a> AstValidator<'a> {
         }
     }
 
+    /// This ensures that items can only be `unsafe` (or unmarked) outside of extern
+    /// blocks.
+    ///
+    /// This additionally ensures that within extern blocks, items can only be
+    /// `safe`/`unsafe` inside of a `unsafe`-adorned extern block.
     fn check_item_safety(&self, span: Span, safety: Safety) {
         match self.extern_mod_safety {
             Some(extern_safety) => {
@@ -1177,6 +1182,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }
             ItemKind::Static(box StaticItem { expr, safety, .. }) => {
                 self.check_item_safety(item.span, *safety);
+                if matches!(safety, Safety::Unsafe(_)) {
+                    self.dcx().emit_err(errors::UnsafeStatic { span: item.span });
+                }
 
                 if expr.is_none() {
                     self.dcx().emit_err(errors::StaticWithoutBody {

compiler/rustc_ast_passes/src/errors.rs

@@ -224,6 +224,13 @@ pub struct InvalidSafetyOnBareFn {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(ast_passes_unsafe_static)]
+pub struct UnsafeStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(ast_passes_bound_in_context)]
 pub struct BoundInContext<'a> {

compiler/rustc_builtin_macros/src/cmdline_attrs.rs

@@ -4,6 +4,7 @@ use crate::errors;
 use rustc_ast::attr::mk_attr;
 use rustc_ast::token;
 use rustc_ast::{self as ast, AttrItem, AttrStyle};
+use rustc_parse::parser::ForceCollect;
 use rustc_parse::{new_parser_from_source_str, unwrap_or_emit_fatal};
 use rustc_session::parse::ParseSess;
 use rustc_span::FileName;
@@ -17,13 +18,14 @@ pub fn inject(krate: &mut ast::Crate, psess: &ParseSess, attrs: &[String]) {
         ));
 
         let start_span = parser.token.span;
-        let AttrItem { unsafety, path, args, tokens: _ } = match parser.parse_attr_item(false) {
-            Ok(ai) => ai,
-            Err(err) => {
-                err.emit();
-                continue;
-            }
-        };
+        let AttrItem { unsafety, path, args, tokens: _ } =
+            match parser.parse_attr_item(ForceCollect::No) {
+                Ok(ai) => ai,
+                Err(err) => {
+                    err.emit();
+                    continue;
+                }
+            };
         let end_span = parser.token.span;
         if parser.token != token::Eof {
             psess.dcx().emit_err(errors::InvalidCrateAttr { span: start_span.to(end_span) });

compiler/rustc_parse/messages.ftl

@@ -524,6 +524,8 @@ parse_mismatched_closing_delimiter = mismatched closing delimiter: `{$delimiter}
     .label_opening_candidate = closing delimiter possibly meant for this
     .label_unclosed = unclosed delimiter
 
+parse_misplaced_return_type = place the return type after the function parameters
+
 parse_missing_comma_after_match_arm = expected `,` following `match` arm
     .suggestion = missing a comma here to end this `match` arm
 

compiler/rustc_parse/src/errors.rs

@@ -1502,6 +1502,20 @@ pub(crate) struct FnPtrWithGenerics {
     pub sugg: Option<FnPtrWithGenericsSugg>,
 }
 
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(
+    parse_misplaced_return_type,
+    style = "verbose",
+    applicability = "maybe-incorrect"
+)]
+pub(crate) struct MisplacedReturnType {
+    #[suggestion_part(code = " {snippet}")]
+    pub fn_params_end: Span,
+    pub snippet: String,
+    #[suggestion_part(code = "")]
+    pub ret_ty_span: Span,
+}
+
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(parse_suggestion, applicability = "maybe-incorrect")]
 pub(crate) struct FnPtrWithGenericsSugg {
@@ -1516,7 +1530,6 @@ pub(crate) struct FnPtrWithGenericsSugg {
 
 pub(crate) struct FnTraitMissingParen {
     pub span: Span,
-    pub machine_applicable: bool,
 }
 
 impl Subdiagnostic for FnTraitMissingParen {
@@ -1526,16 +1539,11 @@ impl Subdiagnostic for FnTraitMissingParen {
         _: &F,
     ) {
         diag.span_label(self.span, crate::fluent_generated::parse_fn_trait_missing_paren);
-        let applicability = if self.machine_applicable {
-            Applicability::MachineApplicable
-        } else {
-            Applicability::MaybeIncorrect
-        };
         diag.span_suggestion_short(
             self.span.shrink_to_hi(),
             crate::fluent_generated::parse_add_paren,
             "()",
-            applicability,
+            Applicability::MachineApplicable,
         );
     }
 }

compiler/rustc_parse/src/parser/attr.rs

@@ -124,7 +124,7 @@ impl<'a> Parser<'a> {
                 if this.eat(&token::Not) { ast::AttrStyle::Inner } else { ast::AttrStyle::Outer };
 
             this.expect(&token::OpenDelim(Delimiter::Bracket))?;
-            let item = this.parse_attr_item(false)?;
+            let item = this.parse_attr_item(ForceCollect::No)?;
             this.expect(&token::CloseDelim(Delimiter::Bracket))?;
             let attr_sp = lo.to(this.prev_token.span);
 
@@ -248,16 +248,15 @@ impl<'a> Parser<'a> {
     ///     PATH
     ///     PATH `=` UNSUFFIXED_LIT
     /// The delimiters or `=` are still put into the resulting token stream.
-    pub fn parse_attr_item(&mut self, capture_tokens: bool) -> PResult<'a, ast::AttrItem> {
+    pub fn parse_attr_item(&mut self, force_collect: ForceCollect) -> PResult<'a, ast::AttrItem> {
         maybe_whole!(self, NtMeta, |attr| attr.into_inner());
 
-        let do_parse = |this: &mut Self| {
+        let do_parse = |this: &mut Self, _empty_attrs| {
             let is_unsafe = this.eat_keyword(kw::Unsafe);
             let unsafety = if is_unsafe {
                 let unsafe_span = this.prev_token.span;
                 this.psess.gated_spans.gate(sym::unsafe_attributes, unsafe_span);
                 this.expect(&token::OpenDelim(Delimiter::Parenthesis))?;
-
                 ast::Safety::Unsafe(unsafe_span)
             } else {
                 ast::Safety::Default
@@ -268,10 +267,10 @@ impl<'a> Parser<'a> {
             if is_unsafe {
                 this.expect(&token::CloseDelim(Delimiter::Parenthesis))?;
             }
-            Ok(ast::AttrItem { unsafety, path, args, tokens: None })
+            Ok((ast::AttrItem { unsafety, path, args, tokens: None }, false))
         };
-        // Attr items don't have attributes
-        if capture_tokens { self.collect_tokens_no_attrs(do_parse) } else { do_parse(self) }
+        // Attr items don't have attributes.
+        self.collect_tokens_trailing_token(AttrWrapper::empty(), force_collect, do_parse)
     }
 
     /// Parses attributes that appear after the opening of an item. These should
@@ -303,17 +302,13 @@ impl<'a> Parser<'a> {
                 None
             };
             if let Some(attr) = attr {
-                let end_pos = self.num_bump_calls;
-                // If we are currently capturing tokens, mark the location of this inner attribute.
-                // If capturing ends up creating a `LazyAttrTokenStream`, we will include
-                // this replace range with it, removing the inner attribute from the final
-                // `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).
-                let range = start_pos..end_pos;
+                // If we are currently capturing tokens (i.e. we are within a call to
+                // `Parser::collect_tokens_trailing_tokens`) record the token positions of this
+                // inner attribute, for possible later processing in a `LazyAttrTokenStream`.
                 if let Capturing::Yes = self.capture_state.capturing {
-                    self.capture_state.inner_attr_ranges.insert(attr.id, (range, None));
+                    let end_pos = self.num_bump_calls;
+                    let range = start_pos..end_pos;
+                    self.capture_state.inner_attr_ranges.insert(attr.id, range);
                 }
                 attrs.push(attr);
             } else {
@@ -344,7 +339,7 @@ impl<'a> Parser<'a> {
         let mut expanded_attrs = Vec::with_capacity(1);
         while self.token.kind != token::Eof {
             let lo = self.token.span;
-            let item = self.parse_attr_item(true)?;
+            let item = self.parse_attr_item(ForceCollect::Yes)?;
             expanded_attrs.push((item, lo.to(self.prev_token.span)));
             if !self.eat(&token::Comma) {
                 break;
@@ -463,7 +458,8 @@ impl<'a> Parser<'a> {
     }
 }
 
-/// The attributes are complete if all attributes are either a doc comment or a builtin attribute other than `cfg_attr`
+/// The attributes are complete if all attributes are either a doc comment or a
+/// builtin attribute other than `cfg_attr`.
 pub fn is_complete(attrs: &[ast::Attribute]) -> bool {
     attrs.iter().all(|attr| {
         attr.is_doc_comment()