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Diffstat (limited to 'compiler/rustc_parse/src/parser/item.rs')
-rw-r--r--compiler/rustc_parse/src/parser/item.rs68
1 files changed, 48 insertions, 20 deletions
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 607adaf0829..ca89eb1e2cf 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -116,7 +116,8 @@ impl<'a> Parser<'a> {
 
 impl<'a> Parser<'a> {
     pub fn parse_item(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<Box<Item>>> {
-        let fn_parse_mode = FnParseMode { req_name: |_| true, req_body: true };
+        let fn_parse_mode =
+            FnParseMode { req_name: |_| true, context: FnContext::Free, req_body: true };
         self.parse_item_(fn_parse_mode, force_collect).map(|i| i.map(Box::new))
     }
 
@@ -975,7 +976,8 @@ impl<'a> Parser<'a> {
         &mut self,
         force_collect: ForceCollect,
     ) -> PResult<'a, Option<Option<Box<AssocItem>>>> {
-        let fn_parse_mode = FnParseMode { req_name: |_| true, req_body: true };
+        let fn_parse_mode =
+            FnParseMode { req_name: |_| true, context: FnContext::Impl, req_body: true };
         self.parse_assoc_item(fn_parse_mode, force_collect)
     }
 
@@ -983,8 +985,11 @@ impl<'a> Parser<'a> {
         &mut self,
         force_collect: ForceCollect,
     ) -> PResult<'a, Option<Option<Box<AssocItem>>>> {
-        let fn_parse_mode =
-            FnParseMode { req_name: |edition| edition >= Edition::Edition2018, req_body: false };
+        let fn_parse_mode = FnParseMode {
+            req_name: |edition| edition >= Edition::Edition2018,
+            context: FnContext::Trait,
+            req_body: false,
+        };
         self.parse_assoc_item(fn_parse_mode, force_collect)
     }
 
@@ -1261,7 +1266,8 @@ impl<'a> Parser<'a> {
         &mut self,
         force_collect: ForceCollect,
     ) -> PResult<'a, Option<Option<Box<ForeignItem>>>> {
-        let fn_parse_mode = FnParseMode { req_name: |_| true, req_body: false };
+        let fn_parse_mode =
+            FnParseMode { req_name: |_| true, context: FnContext::Free, req_body: false };
         Ok(self.parse_item_(fn_parse_mode, force_collect)?.map(
             |Item { attrs, id, span, vis, kind, tokens }| {
                 let kind = match ForeignItemKind::try_from(kind) {
@@ -2135,7 +2141,8 @@ impl<'a> Parser<'a> {
                 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 };
+                let fn_parse_mode =
+                    FnParseMode { req_name: |_| true, context: FnContext::Free, req_body: true };
                 match self.parse_fn(
                     &mut AttrVec::new(),
                     fn_parse_mode,
@@ -2403,6 +2410,9 @@ pub(crate) struct FnParseMode {
     ///   * The span is from Edition 2015. In particular, you can get a
     ///     2015 span inside a 2021 crate using macros.
     pub(super) req_name: ReqName,
+    /// The context in which this function is parsed, used for diagnostics.
+    /// This indicates the fn is a free function or method and so on.
+    pub(super) context: FnContext,
     /// If this flag is set to `true`, then plain, semicolon-terminated function
     /// prototypes are not allowed here.
     ///
@@ -2424,6 +2434,18 @@ pub(crate) struct FnParseMode {
     pub(super) req_body: bool,
 }
 
+/// The context in which a function is parsed.
+/// FIXME(estebank, xizheyin): Use more variants.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub(crate) enum FnContext {
+    /// Free context.
+    Free,
+    /// A Trait context.
+    Trait,
+    /// An Impl block.
+    Impl,
+}
+
 /// Parsing of functions and methods.
 impl<'a> Parser<'a> {
     /// Parse a function starting from the front matter (`const ...`) to the body `{ ... }` or `;`.
@@ -2439,11 +2461,8 @@ impl<'a> Parser<'a> {
         let header = self.parse_fn_front_matter(vis, case, FrontMatterParsingMode::Function)?; // `const ... fn`
         let ident = self.parse_ident()?; // `foo`
         let mut generics = self.parse_generics()?; // `<'a, T, ...>`
-        let decl = match self.parse_fn_decl(
-            fn_parse_mode.req_name,
-            AllowPlus::Yes,
-            RecoverReturnSign::Yes,
-        ) {
+        let decl = match self.parse_fn_decl(&fn_parse_mode, AllowPlus::Yes, RecoverReturnSign::Yes)
+        {
             Ok(decl) => decl,
             Err(old_err) => {
                 // If we see `for Ty ...` then user probably meant `impl` item.
@@ -2961,18 +2980,21 @@ impl<'a> Parser<'a> {
     /// Parses the parameter list and result type of a function declaration.
     pub(super) fn parse_fn_decl(
         &mut self,
-        req_name: ReqName,
+        fn_parse_mode: &FnParseMode,
         ret_allow_plus: AllowPlus,
         recover_return_sign: RecoverReturnSign,
     ) -> PResult<'a, Box<FnDecl>> {
         Ok(Box::new(FnDecl {
-            inputs: self.parse_fn_params(req_name)?,
+            inputs: self.parse_fn_params(fn_parse_mode)?,
             output: self.parse_ret_ty(ret_allow_plus, RecoverQPath::Yes, recover_return_sign)?,
         }))
     }
 
     /// Parses the parameter list of a function, including the `(` and `)` delimiters.
-    pub(super) fn parse_fn_params(&mut self, req_name: ReqName) -> PResult<'a, ThinVec<Param>> {
+    pub(super) fn parse_fn_params(
+        &mut self,
+        fn_parse_mode: &FnParseMode,
+    ) -> PResult<'a, ThinVec<Param>> {
         let mut first_param = true;
         // Parse the arguments, starting out with `self` being allowed...
         if self.token != TokenKind::OpenParen
@@ -2988,7 +3010,7 @@ impl<'a> Parser<'a> {
         let (mut params, _) = self.parse_paren_comma_seq(|p| {
             p.recover_vcs_conflict_marker();
             let snapshot = p.create_snapshot_for_diagnostic();
-            let param = p.parse_param_general(req_name, first_param, true).or_else(|e| {
+            let param = p.parse_param_general(fn_parse_mode, first_param, true).or_else(|e| {
                 let guar = e.emit();
                 // When parsing a param failed, we should check to make the span of the param
                 // not contain '(' before it.
@@ -3019,7 +3041,7 @@ impl<'a> Parser<'a> {
     /// - `recover_arg_parse` is used to recover from a failed argument parse.
     pub(super) fn parse_param_general(
         &mut self,
-        req_name: ReqName,
+        fn_parse_mode: &FnParseMode,
         first_param: bool,
         recover_arg_parse: bool,
     ) -> PResult<'a, Param> {
@@ -3035,16 +3057,22 @@ impl<'a> Parser<'a> {
 
             let is_name_required = match this.token.kind {
                 token::DotDotDot => false,
-                _ => req_name(this.token.span.with_neighbor(this.prev_token.span).edition()),
+                _ => (fn_parse_mode.req_name)(
+                    this.token.span.with_neighbor(this.prev_token.span).edition(),
+                ),
             };
             let (pat, ty) = if is_name_required || this.is_named_param() {
                 debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required);
                 let (pat, colon) = this.parse_fn_param_pat_colon()?;
                 if !colon {
                     let mut err = this.unexpected().unwrap_err();
-                    return if let Some(ident) =
-                        this.parameter_without_type(&mut err, pat, is_name_required, first_param)
-                    {
+                    return if let Some(ident) = this.parameter_without_type(
+                        &mut err,
+                        pat,
+                        is_name_required,
+                        first_param,
+                        fn_parse_mode,
+                    ) {
                         let guar = err.emit();
                         Ok((dummy_arg(ident, guar), Trailing::No, UsePreAttrPos::No))
                     } else {