diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/path.rs')
| -rw-r--r-- | compiler/rustc_parse/src/parser/path.rs | 210 |
1 files changed, 159 insertions, 51 deletions
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs index e7cad74b4dd..fcedc1a4af3 100644 --- a/compiler/rustc_parse/src/parser/path.rs +++ b/compiler/rustc_parse/src/parser/path.rs @@ -1,15 +1,17 @@ use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign}; use super::{Parser, Restrictions, TokenType}; use crate::errors::PathSingleColon; +use crate::parser::{CommaRecoveryMode, RecoverColon, RecoverComma}; use crate::{errors, maybe_whole}; +use ast::token::IdentIsRaw; use rustc_ast::ptr::P; use rustc_ast::token::{self, Delimiter, Token, TokenKind}; use rustc_ast::{ - self as ast, AngleBracketedArg, AngleBracketedArgs, AnonConst, AssocConstraint, - AssocConstraintKind, BlockCheckMode, GenericArg, GenericArgs, Generics, ParenthesizedArgs, + self as ast, AngleBracketedArg, AngleBracketedArgs, AnonConst, AssocItemConstraint, + AssocItemConstraintKind, BlockCheckMode, GenericArg, GenericArgs, Generics, ParenthesizedArgs, Path, PathSegment, QSelf, }; -use rustc_errors::{Applicability, PResult}; +use rustc_errors::{Applicability, Diag, PResult}; use rustc_span::symbol::{kw, sym, Ident}; use rustc_span::{BytePos, Span}; use std::mem; @@ -93,12 +95,15 @@ impl<'a> Parser<'a> { debug!("parse_qpath: (decrement) count={:?}", self.unmatched_angle_bracket_count); } - if !self.recover_colon_before_qpath_proj() { - self.expect(&token::ModSep)?; + let is_import_coupler = self.is_import_coupler(); + if !is_import_coupler && !self.recover_colon_before_qpath_proj() { + self.expect(&token::PathSep)?; } let qself = P(QSelf { ty, path_span, position: path.segments.len() }); - self.parse_path_segments(&mut path.segments, style, None)?; + if !is_import_coupler { + self.parse_path_segments(&mut path.segments, style, None)?; + } Ok(( qself, @@ -158,7 +163,7 @@ impl<'a> Parser<'a> { style: PathStyle, ty_generics: Option<&Generics>, ) -> PResult<'a, Path> { - let reject_generics_if_mod_style = |parser: &Parser<'_>, path: &Path| { + let reject_generics_if_mod_style = |parser: &Parser<'_>, path: Path| { // Ensure generic arguments don't end up in attribute paths, such as: // // macro_rules! m { @@ -176,21 +181,26 @@ impl<'a> Parser<'a> { .map(|arg| arg.span()) .collect::<Vec<_>>(); parser.dcx().emit_err(errors::GenericsInPath { span }); + // Ignore these arguments to prevent unexpected behaviors. + let segments = path + .segments + .iter() + .map(|segment| PathSegment { ident: segment.ident, id: segment.id, args: None }) + .collect(); + Path { segments, ..path } + } else { + path } }; - maybe_whole!(self, NtPath, |path| { - reject_generics_if_mod_style(self, &path); - path.into_inner() - }); + maybe_whole!(self, NtPath, |path| reject_generics_if_mod_style(self, path.into_inner())); if let token::Interpolated(nt) = &self.token.kind { - if let token::NtTy(ty) = &nt.0 { + if let token::NtTy(ty) = &**nt { if let ast::TyKind::Path(None, path) = &ty.kind { let path = path.clone(); self.bump(); - reject_generics_if_mod_style(self, &path); - return Ok(path); + return Ok(reject_generics_if_mod_style(self, path)); } } } @@ -198,7 +208,7 @@ 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)?; @@ -230,11 +240,11 @@ 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 @@ -249,7 +259,7 @@ impl<'a> Parser<'a> { self.dcx().emit_err(PathSingleColon { span: self.prev_token.span, type_ascription: self - .sess + .psess .unstable_features .is_nightly_build() .then_some(()), @@ -289,7 +299,7 @@ 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 @@ -297,11 +307,10 @@ impl<'a> Parser<'a> { // parsing a new path. if style == PathStyle::Expr { self.unmatched_angle_bracket_count = 0; - self.max_angle_bracket_count = 0; } // 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>` @@ -321,7 +330,7 @@ impl<'a> Parser<'a> { err = self.dcx().create_err(PathSingleColon { span: self.token.span, type_ascription: self - .sess + .psess .unstable_features .is_nightly_build() .then_some(()), @@ -372,7 +381,38 @@ impl<'a> Parser<'a> { .into() } else { // `(T, U) -> R` - let (inputs, _) = self.parse_paren_comma_seq(|p| p.parse_ty())?; + + let prev_token_before_parsing = self.prev_token.clone(); + let token_before_parsing = self.token.clone(); + let mut snapshot = None; + if self.may_recover() + && prev_token_before_parsing.kind == token::PathSep + && (style == PathStyle::Expr && self.token.can_begin_expr() + || style == PathStyle::Pat && self.token.can_begin_pattern()) + { + snapshot = Some(self.create_snapshot_for_diagnostic()); + } + + 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::PathSep => { + error.span_label( + prev_token_before_parsing.span.to(token_before_parsing.span), + "while parsing this parenthesized list of type arguments starting here", + ); + + if let Some(mut snapshot) = snapshot { + snapshot.recover_fn_call_leading_path_sep( + style, + prev_token_before_parsing, + &mut error, + ) + } + + return Err(error); + } + Err(error) => return Err(error), + }; let inputs_span = lo.to(self.prev_token.span); let output = self.parse_ret_ty(AllowPlus::No, RecoverQPath::No, RecoverReturnSign::No)?; @@ -390,7 +430,7 @@ impl<'a> Parser<'a> { pub(super) fn parse_path_segment_ident(&mut self) -> PResult<'a, Ident> { match self.token.ident() { - Some((ident, false)) if ident.is_path_segment_keyword() => { + Some((ident, IdentIsRaw::No)) if ident.is_path_segment_keyword() => { self.bump(); Ok(ident) } @@ -398,6 +438,66 @@ impl<'a> Parser<'a> { } } + /// Recover `$path::(...)` as `$path(...)`. + /// + /// ```ignore (diagnostics) + /// foo::(420, "bar") + /// ^^ remove extra separator to make the function call + /// // or + /// match x { + /// Foo::(420, "bar") => { ... }, + /// ^^ remove extra separator to turn this into tuple struct pattern + /// _ => { ... }, + /// } + /// ``` + fn recover_fn_call_leading_path_sep( + &mut self, + style: PathStyle, + prev_token_before_parsing: Token, + error: &mut Diag<'_>, + ) { + match style { + PathStyle::Expr + if let Ok(_) = self + .parse_paren_comma_seq(|p| p.parse_expr()) + .map_err(|error| error.cancel()) => {} + PathStyle::Pat + if let Ok(_) = self + .parse_paren_comma_seq(|p| { + p.parse_pat_allow_top_alt( + None, + RecoverComma::No, + RecoverColon::No, + CommaRecoveryMode::LikelyTuple, + ) + }) + .map_err(|error| error.cancel()) => {} + _ => { + return; + } + } + + if let token::PathSep | token::RArrow = self.token.kind { + return; + } + + error.span_suggestion_verbose( + prev_token_before_parsing.span, + format!( + "consider removing the `::` here to {}", + match style { + PathStyle::Expr => "call the expression", + PathStyle::Pat => "turn this into a tuple struct pattern", + _ => { + return; + } + } + ), + "", + Applicability::MaybeIncorrect, + ); + } + /// Parses generic args (within a path segment) with recovery for extra leading angle brackets. /// For the purposes of understanding the parsing logic of generic arguments, this function /// can be thought of being the same as just calling `self.parse_angle_args()` if the source @@ -567,7 +667,7 @@ impl<'a> Parser<'a> { // Add `>` to the list of expected tokens. self.check(&token::Gt); // Handle `,` to `;` substitution - let mut err = self.unexpected::<()>().unwrap_err(); + let mut err = self.unexpected().unwrap_err(); self.bump(); err.span_suggestion_verbose( self.prev_token.span.until(self.token.span), @@ -620,30 +720,29 @@ impl<'a> Parser<'a> { )); } let kind = if self.eat(&token::Colon) { - // Parse associated type constraint bound. - - let bounds = self.parse_generic_bounds()?; - AssocConstraintKind::Bound { bounds } + AssocItemConstraintKind::Bound { bounds: self.parse_generic_bounds()? } } else if self.eat(&token::Eq) { - self.parse_assoc_equality_term(ident, self.prev_token.span)? + self.parse_assoc_equality_term( + ident, + gen_args.as_ref(), + self.prev_token.span, + )? } else { unreachable!(); }; let span = lo.to(self.prev_token.span); - // Gate associated type bounds, e.g., `Iterator<Item: Ord>`. - if let AssocConstraintKind::Bound { .. } = kind { - if let Some(ast::GenericArgs::Parenthesized(args)) = &gen_args - && args.inputs.is_empty() - && matches!(args.output, ast::FnRetTy::Default(..)) - { - self.sess.gated_spans.gate(sym::return_type_notation, span); - } else { - self.sess.gated_spans.gate(sym::associated_type_bounds, span); - } + + if let AssocItemConstraintKind::Bound { .. } = kind + && let Some(ast::GenericArgs::Parenthesized(args)) = &gen_args + && args.inputs.is_empty() + && let ast::FnRetTy::Default(..) = args.output + { + self.psess.gated_spans.gate(sym::return_type_notation, span); } + let constraint = - AssocConstraint { id: ast::DUMMY_NODE_ID, ident, gen_args, kind, span }; + AssocItemConstraint { id: ast::DUMMY_NODE_ID, ident, gen_args, kind, span }; Ok(Some(AngleBracketedArg::Constraint(constraint))) } else { // we only want to suggest `:` and `=` in contexts where the previous token @@ -662,24 +761,33 @@ impl<'a> Parser<'a> { } /// Parse the term to the right of an associated item equality constraint. - /// That is, parse `<term>` in `Item = <term>`. - /// Right now, this only admits types in `<term>`. + /// + /// That is, parse `$term` in `Item = $term` where `$term` is a type or + /// a const expression (wrapped in curly braces if complex). fn parse_assoc_equality_term( &mut self, ident: Ident, + gen_args: Option<&GenericArgs>, eq: Span, - ) -> PResult<'a, AssocConstraintKind> { + ) -> PResult<'a, AssocItemConstraintKind> { let arg = self.parse_generic_arg(None)?; let span = ident.span.to(self.prev_token.span); let term = match arg { Some(GenericArg::Type(ty)) => ty.into(), Some(GenericArg::Const(c)) => { - self.sess.gated_spans.gate(sym::associated_const_equality, span); + self.psess.gated_spans.gate(sym::associated_const_equality, span); c.into() } Some(GenericArg::Lifetime(lt)) => { - self.dcx().emit_err(errors::AssocLifetime { span, lifetime: lt.ident.span }); - self.mk_ty(span, ast::TyKind::Err).into() + let guar = self.dcx().emit_err(errors::LifetimeInEqConstraint { + span: lt.ident.span, + lifetime: lt.ident, + binding_label: span, + colon_sugg: gen_args + .map_or(ident.span, |args| args.span()) + .between(lt.ident.span), + }); + self.mk_ty(lt.ident.span, ast::TyKind::Err(guar)).into() } None => { let after_eq = eq.shrink_to_hi(); @@ -689,7 +797,7 @@ impl<'a> Parser<'a> { .struct_span_err(after_eq.to(before_next), "missing type to the right of `=`"); if matches!(self.token.kind, token::Comma | token::Gt) { err.span_suggestion( - self.sess.source_map().next_point(eq).to(before_next), + self.psess.source_map().next_point(eq).to(before_next), "to constrain the associated type, add a type after `=`", " TheType", Applicability::HasPlaceholders, @@ -709,7 +817,7 @@ impl<'a> Parser<'a> { return Err(err); } }; - Ok(AssocConstraintKind::Equality { term }) + Ok(AssocItemConstraintKind::Equality { term }) } /// We do not permit arbitrary expressions as const arguments. They must be one of: @@ -779,7 +887,7 @@ impl<'a> Parser<'a> { // type to determine if error recovery has occurred and if the input is not a // syntactically valid type after all. if let ast::TyKind::Slice(inner_ty) | ast::TyKind::Array(inner_ty, _) = &ty.kind - && let ast::TyKind::Err = inner_ty.kind + && let ast::TyKind::Err(_) = inner_ty.kind && let Some(snapshot) = snapshot && let Some(expr) = self.recover_unbraced_const_arg_that_can_begin_ty(snapshot) @@ -830,7 +938,7 @@ impl<'a> Parser<'a> { } /// Given a arg inside of generics, we try to destructure it as if it were the LHS in - /// `LHS = ...`, i.e. an associated type binding. + /// `LHS = ...`, i.e. an associated item binding. /// This returns a bool indicating if there are any `for<'a, 'b>` binder args, the /// identifier, and any GAT arguments. fn get_ident_from_generic_arg( |