From 3ce555f6313e78d3eed80fd22e22ef49f5bd3611 Mon Sep 17 00:00:00 2001 From: xizheyin Date: Thu, 14 Aug 2025 21:30:52 +0800 Subject: Add FnContext in parser for diagnostic Signed-off-by: xizheyin --- compiler/rustc_parse/src/parser/attr.rs | 3 +- compiler/rustc_parse/src/parser/diagnostics.rs | 23 +++++++-- compiler/rustc_parse/src/parser/item.rs | 68 ++++++++++++++++++-------- compiler/rustc_parse/src/parser/mod.rs | 2 +- compiler/rustc_parse/src/parser/path.rs | 12 ++++- compiler/rustc_parse/src/parser/stmt.rs | 6 +-- compiler/rustc_parse/src/parser/ty.rs | 14 ++++-- 7 files changed, 94 insertions(+), 34 deletions(-) (limited to 'compiler/rustc_parse/src') diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs index 41d3889c448..7f6afeba28c 100644 --- a/compiler/rustc_parse/src/parser/attr.rs +++ b/compiler/rustc_parse/src/parser/attr.rs @@ -11,6 +11,7 @@ use tracing::debug; use super::{ AttrWrapper, Capturing, FnParseMode, ForceCollect, Parser, PathStyle, Trailing, UsePreAttrPos, }; +use crate::parser::FnContext; use crate::{errors, exp, fluent_generated as fluent}; // Public for rustfmt usage @@ -200,7 +201,7 @@ impl<'a> Parser<'a> { AttrWrapper::empty(), true, false, - FnParseMode { req_name: |_| true, req_body: true }, + FnParseMode { req_name: |_| true, context: FnContext::Free, req_body: true }, ForceCollect::No, ) { Ok(Some(item)) => { diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs index a32cd33a260..220e4ac18fc 100644 --- a/compiler/rustc_parse/src/parser/diagnostics.rs +++ b/compiler/rustc_parse/src/parser/diagnostics.rs @@ -44,6 +44,7 @@ use crate::errors::{ UnexpectedConstParamDeclaration, UnexpectedConstParamDeclarationSugg, UnmatchedAngleBrackets, UseEqInstead, WrapType, }; +use crate::parser::FnContext; use crate::parser::attr::InnerAttrPolicy; use crate::{exp, fluent_generated as fluent}; @@ -2246,6 +2247,7 @@ impl<'a> Parser<'a> { pat: Box, require_name: bool, first_param: bool, + fn_parse_mode: &crate::parser::item::FnParseMode, ) -> Option { // If we find a pattern followed by an identifier, it could be an (incorrect) // C-style parameter declaration. @@ -2268,7 +2270,14 @@ impl<'a> Parser<'a> { || self.token == token::Lt || self.token == token::CloseParen) { - let rfc_note = "anonymous parameters are removed in the 2018 edition (see RFC 1685)"; + let maybe_emit_anon_params_note = |this: &mut Self, err: &mut Diag<'_>| { + let ed = this.token.span.with_neighbor(this.prev_token.span).edition(); + if matches!(fn_parse_mode.context, crate::parser::item::FnContext::Trait) + && (fn_parse_mode.req_name)(ed) + { + err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)"); + } + }; let (ident, self_sugg, param_sugg, type_sugg, self_span, param_span, type_span) = match pat.kind { @@ -2305,7 +2314,7 @@ impl<'a> Parser<'a> { "_: ".to_string(), Applicability::MachineApplicable, ); - err.note(rfc_note); + maybe_emit_anon_params_note(self, err); } return None; @@ -2313,7 +2322,13 @@ impl<'a> Parser<'a> { }; // `fn foo(a, b) {}`, `fn foo(a, b) {}` or `fn foo(usize, usize) {}` - if first_param { + if first_param + // Only when the fn is a method, we emit this suggestion. + && matches!( + fn_parse_mode.context, + FnContext::Trait | FnContext::Impl + ) + { err.span_suggestion_verbose( self_span, "if this is a `self` type, give it a parameter name", @@ -2337,7 +2352,7 @@ impl<'a> Parser<'a> { type_sugg, Applicability::MachineApplicable, ); - err.note(rfc_note); + maybe_emit_anon_params_note(self, err); // Don't attempt to recover by using the `X` in `X` as the parameter name. return if self.token == token::Lt { None } else { Some(ident) }; 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>> { - 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>>> { - 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>>> { - 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>>> { - 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> { 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> { + pub(super) fn parse_fn_params( + &mut self, + fn_parse_mode: &FnParseMode, + ) -> PResult<'a, ThinVec> { 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 { diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs index 0a8a0203013..41ed1f95a01 100644 --- a/compiler/rustc_parse/src/parser/mod.rs +++ b/compiler/rustc_parse/src/parser/mod.rs @@ -22,7 +22,7 @@ use std::{fmt, mem, slice}; use attr_wrapper::{AttrWrapper, UsePreAttrPos}; pub use diagnostics::AttemptLocalParseRecovery; pub(crate) use expr::ForbiddenLetReason; -pub(crate) use item::FnParseMode; +pub(crate) use item::{FnContext, FnParseMode}; pub use pat::{CommaRecoveryMode, RecoverColon, RecoverComma}; use path::PathStyle; use rustc_ast::token::{ diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs index a6ec3ea4245..37fc723cd89 100644 --- a/compiler/rustc_parse/src/parser/path.rs +++ b/compiler/rustc_parse/src/parser/path.rs @@ -20,7 +20,9 @@ use crate::errors::{ PathFoundAttributeInParams, PathFoundCVariadicParams, PathSingleColon, PathTripleColon, }; use crate::exp; -use crate::parser::{CommaRecoveryMode, ExprKind, RecoverColon, RecoverComma}; +use crate::parser::{ + CommaRecoveryMode, ExprKind, FnContext, FnParseMode, RecoverColon, RecoverComma, +}; /// Specifies how to parse a path. #[derive(Copy, Clone, PartialEq)] @@ -399,7 +401,13 @@ impl<'a> Parser<'a> { let dcx = self.dcx(); let parse_params_result = self.parse_paren_comma_seq(|p| { - let param = p.parse_param_general(|_| false, false, false); + // Inside parenthesized type arguments, we want types only, not names. + let mode = FnParseMode { + context: FnContext::Free, + req_name: |_| false, + req_body: false, + }; + let param = p.parse_param_general(&mode, false, false); param.map(move |param| { if !matches!(param.pat.kind, PatKind::Missing) { dcx.emit_err(FnPathFoundNamedParams { diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs index 7aacb674253..b4943ff7de6 100644 --- a/compiler/rustc_parse/src/parser/stmt.rs +++ b/compiler/rustc_parse/src/parser/stmt.rs @@ -19,8 +19,8 @@ use super::diagnostics::AttemptLocalParseRecovery; use super::pat::{PatternLocation, RecoverComma}; use super::path::PathStyle; use super::{ - AttrWrapper, BlockMode, FnParseMode, ForceCollect, Parser, Restrictions, SemiColonMode, - Trailing, UsePreAttrPos, + AttrWrapper, BlockMode, FnContext, FnParseMode, ForceCollect, Parser, Restrictions, + SemiColonMode, Trailing, UsePreAttrPos, }; use crate::errors::{self, MalformedLoopLabel}; use crate::exp; @@ -153,7 +153,7 @@ impl<'a> Parser<'a> { attrs.clone(), // FIXME: unwanted clone of attrs false, true, - FnParseMode { req_name: |_| true, req_body: true }, + FnParseMode { req_name: |_| true, context: FnContext::Free, req_body: true }, force_collect, )? { self.mk_stmt(lo.to(item.span), StmtKind::Item(Box::new(item))) diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs index 0d479731e73..290f0a440af 100644 --- a/compiler/rustc_parse/src/parser/ty.rs +++ b/compiler/rustc_parse/src/parser/ty.rs @@ -19,6 +19,7 @@ use crate::errors::{ NestedCVariadicType, ReturnTypesUseThinArrow, }; use crate::parser::item::FrontMatterParsingMode; +use crate::parser::{FnContext, FnParseMode}; use crate::{exp, maybe_recover_from_interpolated_ty_qpath}; /// Signals whether parsing a type should allow `+`. @@ -769,7 +770,12 @@ impl<'a> Parser<'a> { if self.may_recover() && self.token == TokenKind::Lt { self.recover_fn_ptr_with_generics(lo, &mut params, param_insertion_point)?; } - let decl = self.parse_fn_decl(|_| false, AllowPlus::No, recover_return_sign)?; + let mode = crate::parser::item::FnParseMode { + req_name: |_| false, + context: FnContext::Free, + req_body: false, + }; + let decl = self.parse_fn_decl(&mode, AllowPlus::No, recover_return_sign)?; let decl_span = span_start.to(self.prev_token.span); Ok(TyKind::FnPtr(Box::new(FnPtrTy { @@ -1314,7 +1320,8 @@ impl<'a> Parser<'a> { self.bump(); let args_lo = self.token.span; let snapshot = self.create_snapshot_for_diagnostic(); - match self.parse_fn_decl(|_| false, AllowPlus::No, RecoverReturnSign::OnlyFatArrow) { + let mode = FnParseMode { req_name: |_| false, context: FnContext::Free, req_body: false }; + match self.parse_fn_decl(&mode, AllowPlus::No, RecoverReturnSign::OnlyFatArrow) { Ok(decl) => { self.dcx().emit_err(ExpectedFnPathFoundFnKeyword { fn_token_span }); Some(ast::Path { @@ -1400,8 +1407,9 @@ impl<'a> Parser<'a> { // Parse `(T, U) -> R`. let inputs_lo = self.token.span; + let mode = FnParseMode { req_name: |_| false, context: FnContext::Free, req_body: false }; let inputs: ThinVec<_> = - self.parse_fn_params(|_| false)?.into_iter().map(|input| input.ty).collect(); + self.parse_fn_params(&mode)?.into_iter().map(|input| input.ty).collect(); let inputs_span = inputs_lo.to(self.prev_token.span); let output = self.parse_ret_ty(AllowPlus::No, RecoverQPath::No, RecoverReturnSign::No)?; let args = ast::ParenthesizedArgs { -- cgit 1.4.1-3-g733a5