diff options
Diffstat (limited to 'compiler/rustc_parse/src/parser/ty.rs')
-rw-r--r-- | compiler/rustc_parse/src/parser/ty.rs | 125 |
1 files changed, 46 insertions, 79 deletions
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs index 37c441fbecb..04f7eea90ed 100644 --- a/compiler/rustc_parse/src/parser/ty.rs +++ b/compiler/rustc_parse/src/parser/ty.rs @@ -3,8 +3,7 @@ use super::{Parser, PathStyle, TokenType}; use crate::errors::{ self, DynAfterMut, ExpectedFnPathFoundFnKeyword, ExpectedMutOrConstInRawPointerType, FnPointerCannotBeAsync, FnPointerCannotBeConst, FnPtrWithGenerics, FnPtrWithGenericsSugg, - InvalidDynKeyword, LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime, - NegativeBoundsNotSupported, NegativeBoundsNotSupportedSugg, NestedCVariadicType, + InvalidDynKeyword, LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime, NestedCVariadicType, ReturnTypesUseThinArrow, }; use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole}; @@ -14,8 +13,9 @@ use rustc_ast::ptr::P; use rustc_ast::token::{self, Delimiter, Token, TokenKind}; use rustc_ast::util::case::Case; use rustc_ast::{ - self as ast, BareFnTy, FnRetTy, GenericBound, GenericBounds, GenericParam, Generics, Lifetime, - MacCall, MutTy, Mutability, PolyTraitRef, TraitBoundModifier, TraitObjectSyntax, Ty, TyKind, + self as ast, BareFnTy, BoundPolarity, FnRetTy, GenericBound, GenericBounds, GenericParam, + Generics, Lifetime, MacCall, MutTy, Mutability, PolyTraitRef, TraitBoundModifier, + TraitObjectSyntax, Ty, TyKind, }; use rustc_errors::{Applicability, PResult}; use rustc_span::source_map::Span; @@ -23,10 +23,10 @@ use rustc_span::symbol::{kw, sym, Ident}; use rustc_span::Symbol; use thin_vec::{thin_vec, ThinVec}; -/// Any `?` or `~const` modifiers that appear at the start of a bound. +/// Any `?`, `!`, or `~const` modifiers that appear at the start of a bound. struct BoundModifiers { /// `?Trait`. - maybe: Option<Span>, + bound_polarity: BoundPolarity, /// `~const Trait`. maybe_const: Option<Span>, @@ -34,11 +34,13 @@ struct BoundModifiers { impl BoundModifiers { fn to_trait_bound_modifier(&self) -> TraitBoundModifier { - match (self.maybe, self.maybe_const) { - (None, None) => TraitBoundModifier::None, - (Some(_), None) => TraitBoundModifier::Maybe, - (None, Some(_)) => TraitBoundModifier::MaybeConst, - (Some(_), Some(_)) => TraitBoundModifier::MaybeConstMaybe, + match (self.bound_polarity, self.maybe_const) { + (BoundPolarity::Positive, None) => TraitBoundModifier::None, + (BoundPolarity::Negative(_), None) => TraitBoundModifier::Negative, + (BoundPolarity::Maybe(_), None) => TraitBoundModifier::Maybe, + (BoundPolarity::Positive, Some(_)) => TraitBoundModifier::MaybeConst, + (BoundPolarity::Negative(_), Some(_)) => TraitBoundModifier::MaybeConstNegative, + (BoundPolarity::Maybe(_), Some(_)) => TraitBoundModifier::MaybeConstMaybe, } } } @@ -368,7 +370,7 @@ impl<'a> Parser<'a> { fn parse_bare_trait_object(&mut self, lo: Span, allow_plus: AllowPlus) -> PResult<'a, TyKind> { let lt_no_plus = self.check_lifetime() && !self.look_ahead(1, |t| t.is_like_plus()); - let bounds = self.parse_generic_bounds_common(allow_plus, None)?; + let bounds = self.parse_generic_bounds_common(allow_plus)?; if lt_no_plus { self.sess.emit_err(NeedPlusAfterTraitObjectLifetime { span: lo }); } @@ -395,7 +397,7 @@ impl<'a> Parser<'a> { ) -> PResult<'a, TyKind> { if plus { self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded - bounds.append(&mut self.parse_generic_bounds(Some(self.prev_token.span))?); + bounds.append(&mut self.parse_generic_bounds()?); } Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None)) } @@ -598,7 +600,7 @@ impl<'a> Parser<'a> { } }) } - let bounds = self.parse_generic_bounds(None)?; + let bounds = self.parse_generic_bounds()?; *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus); Ok(TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds)) } @@ -629,7 +631,7 @@ impl<'a> Parser<'a> { }; // Always parse bounds greedily for better error recovery. - let bounds = self.parse_generic_bounds(None)?; + let bounds = self.parse_generic_bounds()?; *impl_dyn_multi = bounds.len() > 1 || self.prev_token.kind == TokenKind::BinOp(token::Plus); Ok(TyKind::TraitObject(bounds, syntax)) } @@ -660,23 +662,15 @@ impl<'a> Parser<'a> { } } - pub(super) fn parse_generic_bounds( - &mut self, - colon_span: Option<Span>, - ) -> PResult<'a, GenericBounds> { - self.parse_generic_bounds_common(AllowPlus::Yes, colon_span) + pub(super) fn parse_generic_bounds(&mut self) -> PResult<'a, GenericBounds> { + self.parse_generic_bounds_common(AllowPlus::Yes) } /// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`. /// /// See `parse_generic_bound` for the `BOUND` grammar. - fn parse_generic_bounds_common( - &mut self, - allow_plus: AllowPlus, - colon_span: Option<Span>, - ) -> PResult<'a, GenericBounds> { + fn parse_generic_bounds_common(&mut self, allow_plus: AllowPlus) -> PResult<'a, GenericBounds> { let mut bounds = Vec::new(); - let mut negative_bounds = Vec::new(); // In addition to looping while we find generic bounds: // We continue even if we find a keyword. This is necessary for error recovery on, @@ -693,19 +687,12 @@ impl<'a> Parser<'a> { self.sess.emit_err(InvalidDynKeyword { span: self.token.span }); self.bump(); } - match self.parse_generic_bound()? { - Ok(bound) => bounds.push(bound), - Err(neg_sp) => negative_bounds.push(neg_sp), - } + bounds.push(self.parse_generic_bound()?); if allow_plus == AllowPlus::No || !self.eat_plus() { break; } } - if !negative_bounds.is_empty() { - self.error_negative_bounds(colon_span, &bounds, negative_bounds); - } - Ok(bounds) } @@ -713,55 +700,22 @@ impl<'a> Parser<'a> { fn can_begin_bound(&mut self) -> bool { // This needs to be synchronized with `TokenKind::can_begin_bound`. self.check_path() - || self.check_lifetime() - || self.check(&token::Not) // Used for error reporting only. - || self.check(&token::Question) - || self.check(&token::Tilde) - || self.check_keyword(kw::For) - || self.check(&token::OpenDelim(Delimiter::Parenthesis)) - } - - fn error_negative_bounds( - &self, - colon_span: Option<Span>, - bounds: &[GenericBound], - negative_bounds: Vec<Span>, - ) { - let sub = if let Some(bound_list) = colon_span { - let bound_list = bound_list.to(self.prev_token.span); - let mut new_bound_list = String::new(); - if !bounds.is_empty() { - let mut snippets = bounds.iter().map(|bound| self.span_to_snippet(bound.span())); - while let Some(Ok(snippet)) = snippets.next() { - new_bound_list.push_str(" + "); - new_bound_list.push_str(&snippet); - } - new_bound_list = new_bound_list.replacen(" +", ":", 1); - } - - Some(NegativeBoundsNotSupportedSugg { - bound_list, - num_bounds: negative_bounds.len(), - fixed: new_bound_list, - }) - } else { - None - }; - - let last_span = *negative_bounds.last().expect("no negative bounds, but still error?"); - self.sess.emit_err(NegativeBoundsNotSupported { negative_bounds, last_span, sub }); + || self.check_lifetime() + || self.check(&token::Not) + || self.check(&token::Question) + || self.check(&token::Tilde) + || self.check_keyword(kw::For) + || self.check(&token::OpenDelim(Delimiter::Parenthesis)) } /// Parses a bound according to the grammar: /// ```ebnf /// BOUND = TY_BOUND | LT_BOUND /// ``` - fn parse_generic_bound(&mut self) -> PResult<'a, Result<GenericBound, Span>> { - let anchor_lo = self.prev_token.span; + fn parse_generic_bound(&mut self) -> PResult<'a, GenericBound> { let lo = self.token.span; let has_parens = self.eat(&token::OpenDelim(Delimiter::Parenthesis)); let inner_lo = self.token.span; - let is_negative = self.eat(&token::Not); let modifiers = self.parse_ty_bound_modifiers()?; let bound = if self.token.is_lifetime() { @@ -771,7 +725,7 @@ impl<'a> Parser<'a> { self.parse_generic_ty_bound(lo, has_parens, modifiers)? }; - Ok(if is_negative { Err(anchor_lo.to(self.prev_token.span)) } else { Ok(bound) }) + Ok(bound) } /// Parses a lifetime ("outlives") bound, e.g. `'a`, according to: @@ -799,8 +753,14 @@ impl<'a> Parser<'a> { self.sess.emit_err(errors::TildeConstLifetime { span }); } - if let Some(span) = modifiers.maybe { - self.sess.emit_err(errors::MaybeLifetime { span }); + match modifiers.bound_polarity { + BoundPolarity::Positive => {} + BoundPolarity::Negative(span) => { + self.sess.emit_err(errors::ModifierLifetime { span, sigil: "!" }); + } + BoundPolarity::Maybe(span) => { + self.sess.emit_err(errors::ModifierLifetime { span, sigil: "?" }); + } } } @@ -843,9 +803,16 @@ impl<'a> Parser<'a> { None }; - let maybe = self.eat(&token::Question).then_some(self.prev_token.span); + let bound_polarity = if self.eat(&token::Question) { + BoundPolarity::Maybe(self.prev_token.span) + } else if self.eat(&token::Not) { + self.sess.gated_spans.gate(sym::negative_bounds, self.prev_token.span); + BoundPolarity::Negative(self.prev_token.span) + } else { + BoundPolarity::Positive + }; - Ok(BoundModifiers { maybe, maybe_const }) + Ok(BoundModifiers { bound_polarity, maybe_const }) } /// Parses a type bound according to: |