From 3bc32472008387ab2adca98dcfd0bef6207357c1 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Fri, 28 Jun 2024 19:37:21 -0400 Subject: [PATCH] Move binder and polarity parsing into parse_generic_ty_bound --- compiler/rustc_parse/src/parser/expr.rs | 2 +- compiler/rustc_parse/src/parser/generics.rs | 2 +- compiler/rustc_parse/src/parser/ty.rs | 98 ++++++++++++------- .../higher-ranked/erroneous-lifetime-bound.rs | 5 + .../erroneous-lifetime-bound.stderr | 25 +++++ .../precise-capturing/bound-modifiers.rs | 25 +++++ .../precise-capturing/bound-modifiers.stderr | 87 ++++++++++++++++ 7 files changed, 204 insertions(+), 40 deletions(-) create mode 100644 tests/ui/higher-ranked/erroneous-lifetime-bound.rs create mode 100644 tests/ui/higher-ranked/erroneous-lifetime-bound.stderr create mode 100644 tests/ui/impl-trait/precise-capturing/bound-modifiers.rs create mode 100644 tests/ui/impl-trait/precise-capturing/bound-modifiers.stderr diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index e0c70884fee..ac66edeb95e 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -2327,7 +2327,7 @@ impl<'a> Parser<'a> { let before = self.prev_token.clone(); let binder = if self.check_keyword(kw::For) { let lo = self.token.span; - let lifetime_defs = self.parse_late_bound_lifetime_defs()?; + let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?; let span = lo.to(self.prev_token.span); self.psess.gated_spans.gate(sym::closure_lifetime_binder, span); diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs index fde16ac957d..10c7715c7dc 100644 --- a/compiler/rustc_parse/src/parser/generics.rs +++ b/compiler/rustc_parse/src/parser/generics.rs @@ -457,7 +457,7 @@ impl<'a> Parser<'a> { // * `for<'a> Trait1<'a>: Trait2<'a /* ok */>` // * `(for<'a> Trait1<'a>): Trait2<'a /* not ok */>` // * `for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /* ok */, 'b /* not ok */>` - let lifetime_defs = self.parse_late_bound_lifetime_defs()?; + let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?; // Parse type with mandatory colon and (possibly empty) bounds, // or with mandatory equality sign and the second type. diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs index d2043c353fe..1e5b227aaa9 100644 --- a/compiler/rustc_parse/src/parser/ty.rs +++ b/compiler/rustc_parse/src/parser/ty.rs @@ -18,7 +18,7 @@ use rustc_ast::{ }; use rustc_errors::{Applicability, PResult}; use rustc_span::symbol::{kw, sym, Ident}; -use rustc_span::{Span, Symbol}; +use rustc_span::{ErrorGuaranteed, Span, Symbol}; use thin_vec::{thin_vec, ThinVec}; #[derive(Copy, Clone, PartialEq)] @@ -280,7 +280,7 @@ impl<'a> Parser<'a> { // Function pointer type or bound list (trait object type) starting with a poly-trait. // `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T` // `for<'lt> Trait1<'lt> + Trait2 + 'a` - let lifetime_defs = self.parse_late_bound_lifetime_defs()?; + let (lifetime_defs, _) = self.parse_late_bound_lifetime_defs()?; if self.check_fn_front_matter(false, Case::Sensitive) { self.parse_ty_bare_fn( lo, @@ -833,12 +833,9 @@ impl<'a> Parser<'a> { let lo = self.token.span; let leading_token = self.prev_token.clone(); let has_parens = self.eat(&token::OpenDelim(Delimiter::Parenthesis)); - let inner_lo = self.token.span; - let modifiers = self.parse_trait_bound_modifiers()?; let bound = if self.token.is_lifetime() { - self.error_lt_bound_with_modifiers(modifiers); - self.parse_generic_lt_bound(lo, inner_lo, has_parens)? + self.parse_generic_lt_bound(lo, has_parens)? } else if self.eat_keyword(kw::Use) { // parse precise captures, if any. This is `use<'lt, 'lt, P, P>`; a list of // lifetimes and ident params (including SelfUpper). These are validated later @@ -848,7 +845,7 @@ impl<'a> Parser<'a> { let (args, args_span) = self.parse_precise_capturing_args()?; GenericBound::Use(args, use_span.to(args_span)) } else { - self.parse_generic_ty_bound(lo, has_parens, modifiers, &leading_token)? + self.parse_generic_ty_bound(lo, has_parens, &leading_token)? }; Ok(bound) @@ -858,50 +855,64 @@ impl<'a> Parser<'a> { /// ```ebnf /// LT_BOUND = LIFETIME /// ``` - fn parse_generic_lt_bound( - &mut self, - lo: Span, - inner_lo: Span, - has_parens: bool, - ) -> PResult<'a, GenericBound> { - let bound = GenericBound::Outlives(self.expect_lifetime()); + fn parse_generic_lt_bound(&mut self, lo: Span, has_parens: bool) -> PResult<'a, GenericBound> { + let lt = self.expect_lifetime(); + let bound = GenericBound::Outlives(lt); if has_parens { // FIXME(Centril): Consider not erroring here and accepting `('lt)` instead, // possibly introducing `GenericBound::Paren(P)`? - self.recover_paren_lifetime(lo, inner_lo)?; + self.recover_paren_lifetime(lo, lt.ident.span)?; } Ok(bound) } /// Emits an error if any trait bound modifiers were present. - fn error_lt_bound_with_modifiers(&self, modifiers: TraitBoundModifiers) { - match modifiers.constness { + fn error_lt_bound_with_modifiers( + &self, + modifiers: TraitBoundModifiers, + binder_span: Option, + ) -> ErrorGuaranteed { + let TraitBoundModifiers { constness, asyncness, polarity } = modifiers; + + match constness { BoundConstness::Never => {} BoundConstness::Always(span) | BoundConstness::Maybe(span) => { - self.dcx().emit_err(errors::ModifierLifetime { - span, - modifier: modifiers.constness.as_str(), - }); + return self + .dcx() + .emit_err(errors::ModifierLifetime { span, modifier: constness.as_str() }); } } - match modifiers.polarity { + match polarity { BoundPolarity::Positive => {} BoundPolarity::Negative(span) | BoundPolarity::Maybe(span) => { - self.dcx().emit_err(errors::ModifierLifetime { - span, - modifier: modifiers.polarity.as_str(), - }); + return self + .dcx() + .emit_err(errors::ModifierLifetime { span, modifier: polarity.as_str() }); } } + + match asyncness { + BoundAsyncness::Normal => {} + BoundAsyncness::Async(span) => { + return self + .dcx() + .emit_err(errors::ModifierLifetime { span, modifier: asyncness.as_str() }); + } + } + + if let Some(span) = binder_span { + return self.dcx().emit_err(errors::ModifierLifetime { span, modifier: "for<...>" }); + } + + unreachable!("lifetime bound intercepted in `parse_generic_ty_bound` but no modifiers?") } /// Recover on `('lifetime)` with `(` already eaten. - fn recover_paren_lifetime(&mut self, lo: Span, inner_lo: Span) -> PResult<'a, ()> { - let inner_span = inner_lo.to(self.prev_token.span); + fn recover_paren_lifetime(&mut self, lo: Span, lt_span: Span) -> PResult<'a, ()> { self.expect(&token::CloseDelim(Delimiter::Parenthesis))?; let span = lo.to(self.prev_token.span); - let (sugg, snippet) = if let Ok(snippet) = self.span_to_snippet(inner_span) { + let (sugg, snippet) = if let Ok(snippet) = self.span_to_snippet(lt_span) { (Some(span), snippet) } else { (None, String::new()) @@ -916,7 +927,7 @@ impl<'a> Parser<'a> { /// If no modifiers are present, this does not consume any tokens. /// /// ```ebnf - /// TRAIT_BOUND_MODIFIERS = [["~"] "const"] ["?" | "!"] + /// TRAIT_BOUND_MODIFIERS = [["~"] "const"] ["async"] ["?" | "!"] /// ``` fn parse_trait_bound_modifiers(&mut self) -> PResult<'a, TraitBoundModifiers> { let constness = if self.eat(&token::Tilde) { @@ -970,15 +981,23 @@ impl<'a> Parser<'a> { /// TY_BOUND_NOPAREN = [TRAIT_BOUND_MODIFIERS] [for] SIMPLE_PATH /// ``` /// - /// For example, this grammar accepts `~const ?for<'a: 'b> m::Trait<'a>`. + /// For example, this grammar accepts `for<'a: 'b> ~const ?m::Trait<'a>`. fn parse_generic_ty_bound( &mut self, lo: Span, has_parens: bool, - modifiers: TraitBoundModifiers, leading_token: &Token, ) -> PResult<'a, GenericBound> { - let mut lifetime_defs = self.parse_late_bound_lifetime_defs()?; + let modifiers = self.parse_trait_bound_modifiers()?; + let (mut lifetime_defs, binder_span) = self.parse_late_bound_lifetime_defs()?; + + // Recover erroneous lifetime bound with modifiers or binder. + // e.g. `T: for<'a> 'a` or `T: ~const 'a`. + if self.token.is_lifetime() { + let _: ErrorGuaranteed = self.error_lt_bound_with_modifiers(modifiers, binder_span); + return self.parse_generic_lt_bound(lo, has_parens); + } + let mut path = if self.token.is_keyword(kw::Fn) && self.look_ahead(1, |tok| tok.kind == TokenKind::OpenDelim(Delimiter::Parenthesis)) && let Some(path) = self.recover_path_from_fn() @@ -1094,16 +1113,19 @@ impl<'a> Parser<'a> { } /// Optionally parses `for<$generic_params>`. - pub(super) fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, ThinVec> { + pub(super) fn parse_late_bound_lifetime_defs( + &mut self, + ) -> PResult<'a, (ThinVec, Option)> { if self.eat_keyword(kw::For) { + let lo = self.token.span; self.expect_lt()?; let params = self.parse_generic_params()?; self.expect_gt()?; - // We rely on AST validation to rule out invalid cases: There must not be type - // parameters, and the lifetime parameters must not have bounds. - Ok(params) + // We rely on AST validation to rule out invalid cases: There must not be + // type or const parameters, and parameters must not have bounds. + Ok((params, Some(lo.to(self.prev_token.span)))) } else { - Ok(ThinVec::new()) + Ok((ThinVec::new(), None)) } } diff --git a/tests/ui/higher-ranked/erroneous-lifetime-bound.rs b/tests/ui/higher-ranked/erroneous-lifetime-bound.rs new file mode 100644 index 00000000000..b1720087b5f --- /dev/null +++ b/tests/ui/higher-ranked/erroneous-lifetime-bound.rs @@ -0,0 +1,5 @@ +fn foo() where T: for<'a> 'a {} +//~^ ERROR `for<...>` may only modify trait bounds, not lifetime bounds +//~| ERROR use of undeclared lifetime name `'a` [E0261] + +fn main() {} diff --git a/tests/ui/higher-ranked/erroneous-lifetime-bound.stderr b/tests/ui/higher-ranked/erroneous-lifetime-bound.stderr new file mode 100644 index 00000000000..5b104f45d23 --- /dev/null +++ b/tests/ui/higher-ranked/erroneous-lifetime-bound.stderr @@ -0,0 +1,25 @@ +error: `for<...>` may only modify trait bounds, not lifetime bounds + --> $DIR/erroneous-lifetime-bound.rs:1:25 + | +LL | fn foo() where T: for<'a> 'a {} + | ^^^^ + +error[E0261]: use of undeclared lifetime name `'a` + --> $DIR/erroneous-lifetime-bound.rs:1:30 + | +LL | fn foo() where T: for<'a> 'a {} + | ^^ undeclared lifetime + | + = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html +help: consider making the bound lifetime-generic with a new `'a` lifetime + | +LL | fn foo() where for<'a> T: for<'a> 'a {} + | +++++++ +help: consider introducing lifetime `'a` here + | +LL | fn foo<'a, T>() where T: for<'a> 'a {} + | +++ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0261`. diff --git a/tests/ui/impl-trait/precise-capturing/bound-modifiers.rs b/tests/ui/impl-trait/precise-capturing/bound-modifiers.rs new file mode 100644 index 00000000000..15f21882628 --- /dev/null +++ b/tests/ui/impl-trait/precise-capturing/bound-modifiers.rs @@ -0,0 +1,25 @@ +//@ edition: 2021 + +#![feature(precise_capturing)] + +fn polarity() -> impl Sized + ?use<> {} +//~^ ERROR expected identifier, found keyword `use` +//~| ERROR cannot find trait `r#use` in this scope +//~| WARN relaxing a default bound only does something for `?Sized` +//~| WARN relaxing a default bound only does something for `?Sized` + +fn asyncness() -> impl Sized + async use<> {} +//~^ ERROR expected identifier, found keyword `use` +//~| ERROR cannot find trait `r#use` in this scope +//~| ERROR async closures are unstable + +fn constness() -> impl Sized + const use<> {} +//~^ ERROR expected identifier, found keyword `use` +//~| ERROR cannot find trait `r#use` in this scope +//~| ERROR const trait impls are experimental + +fn binder() -> impl Sized + for<'a> use<> {} +//~^ ERROR expected identifier, found keyword `use` +//~| ERROR cannot find trait `r#use` in this scope + +fn main() {} diff --git a/tests/ui/impl-trait/precise-capturing/bound-modifiers.stderr b/tests/ui/impl-trait/precise-capturing/bound-modifiers.stderr new file mode 100644 index 00000000000..4602225e7b9 --- /dev/null +++ b/tests/ui/impl-trait/precise-capturing/bound-modifiers.stderr @@ -0,0 +1,87 @@ +error: expected identifier, found keyword `use` + --> $DIR/bound-modifiers.rs:5:32 + | +LL | fn polarity() -> impl Sized + ?use<> {} + | ^^^ expected identifier, found keyword + +error: expected identifier, found keyword `use` + --> $DIR/bound-modifiers.rs:11:38 + | +LL | fn asyncness() -> impl Sized + async use<> {} + | ^^^ expected identifier, found keyword + +error: expected identifier, found keyword `use` + --> $DIR/bound-modifiers.rs:16:38 + | +LL | fn constness() -> impl Sized + const use<> {} + | ^^^ expected identifier, found keyword + +error: expected identifier, found keyword `use` + --> $DIR/bound-modifiers.rs:21:37 + | +LL | fn binder() -> impl Sized + for<'a> use<> {} + | ^^^ expected identifier, found keyword + +error[E0405]: cannot find trait `r#use` in this scope + --> $DIR/bound-modifiers.rs:5:32 + | +LL | fn polarity() -> impl Sized + ?use<> {} + | ^^^ not found in this scope + +error[E0405]: cannot find trait `r#use` in this scope + --> $DIR/bound-modifiers.rs:11:38 + | +LL | fn asyncness() -> impl Sized + async use<> {} + | ^^^ not found in this scope + +error[E0405]: cannot find trait `r#use` in this scope + --> $DIR/bound-modifiers.rs:16:38 + | +LL | fn constness() -> impl Sized + const use<> {} + | ^^^ not found in this scope + +error[E0405]: cannot find trait `r#use` in this scope + --> $DIR/bound-modifiers.rs:21:37 + | +LL | fn binder() -> impl Sized + for<'a> use<> {} + | ^^^ not found in this scope + +error[E0658]: async closures are unstable + --> $DIR/bound-modifiers.rs:11:32 + | +LL | fn asyncness() -> impl Sized + async use<> {} + | ^^^^^ + | + = note: see issue #62290 for more information + = help: add `#![feature(async_closure)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + = help: to use an async block, remove the `||`: `async {` + +error[E0658]: const trait impls are experimental + --> $DIR/bound-modifiers.rs:16:32 + | +LL | fn constness() -> impl Sized + const use<> {} + | ^^^^^ + | + = note: see issue #67792 for more information + = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/bound-modifiers.rs:5:31 + | +LL | fn polarity() -> impl Sized + ?use<> {} + | ^^^^^^ + +warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default + --> $DIR/bound-modifiers.rs:5:31 + | +LL | fn polarity() -> impl Sized + ?use<> {} + | ^^^^^^ + | + = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` + +error: aborting due to 10 previous errors; 2 warnings emitted + +Some errors have detailed explanations: E0405, E0658. +For more information about an error, try `rustc --explain E0405`.