diff options
| -rw-r--r-- | compiler/rustc_parse/src/parser/ty.rs | 39 | ||||
| -rw-r--r-- | src/test/ui/parser/trait-object-delimiters.rs | 17 | ||||
| -rw-r--r-- | src/test/ui/parser/trait-object-delimiters.stderr | 77 |
3 files changed, 130 insertions, 3 deletions
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs index 0f7b8ebd376..d537741c749 100644 --- a/compiler/rustc_parse/src/parser/ty.rs +++ b/compiler/rustc_parse/src/parser/ty.rs @@ -470,7 +470,7 @@ impl<'a> Parser<'a> { /// Is a `dyn B0 + ... + Bn` type allowed here? fn is_explicit_dyn_type(&mut self) -> bool { self.check_keyword(kw::Dyn) - && (self.token.uninterpolated_span().rust_2018() + && (!self.token.uninterpolated_span().rust_2015() || self.look_ahead(1, |t| { t.can_begin_bound() && !can_continue_type_after_non_fn_ident(t) })) @@ -539,7 +539,21 @@ impl<'a> Parser<'a> { ) -> PResult<'a, GenericBounds> { let mut bounds = Vec::new(); let mut negative_bounds = Vec::new(); - while self.can_begin_bound() { + + while self.can_begin_bound() || self.token.is_keyword(kw::Dyn) { + if self.token.is_keyword(kw::Dyn) { + // Account for `&dyn Trait + dyn Other`. + self.struct_span_err(self.token.span, "invalid `dyn` keyword") + .help("`dyn` is only needed at the start of a trait `+`-separated list") + .span_suggestion( + self.token.span, + "remove this keyword", + String::new(), + Applicability::MachineApplicable, + ) + .emit(); + self.bump(); + } match self.parse_generic_bound()? { Ok(bound) => bounds.push(bound), Err(neg_sp) => negative_bounds.push(neg_sp), @@ -721,7 +735,26 @@ impl<'a> Parser<'a> { let lifetime_defs = self.parse_late_bound_lifetime_defs()?; let path = self.parse_path(PathStyle::Type)?; if has_parens { - self.expect(&token::CloseDelim(token::Paren))?; + if self.token.is_like_plus() { + // Someone has written something like `&dyn (Trait + Other)`. The correct code + // would be `&(dyn Trait + Other)`, but we don't have access to the appropriate + // span to suggest that. When written as `&dyn Trait + Other`, an appropriate + // suggestion is given. + let bounds = vec![]; + self.parse_remaining_bounds(bounds, true)?; + self.expect(&token::CloseDelim(token::Paren))?; + let sp = vec![lo, self.prev_token.span]; + let sugg: Vec<_> = sp.iter().map(|sp| (*sp, String::new())).collect(); + self.struct_span_err(sp, "incorrect braces around trait bounds") + .multipart_suggestion( + "remove the parentheses", + sugg, + Applicability::MachineApplicable, + ) + .emit(); + } else { + self.expect(&token::CloseDelim(token::Paren))?; + } } let modifier = modifiers.to_trait_bound_modifier(); diff --git a/src/test/ui/parser/trait-object-delimiters.rs b/src/test/ui/parser/trait-object-delimiters.rs new file mode 100644 index 00000000000..650ab572261 --- /dev/null +++ b/src/test/ui/parser/trait-object-delimiters.rs @@ -0,0 +1,17 @@ +// edition:2018 + +fn foo1(_: &dyn Drop + AsRef<str>) {} //~ ERROR ambiguous `+` in a type +//~^ ERROR only auto traits can be used as additional traits in a trait object + +fn foo2(_: &dyn (Drop + AsRef<str>)) {} //~ ERROR incorrect braces around trait bounds + +fn foo3(_: &dyn {Drop + AsRef<str>}) {} //~ ERROR expected parameter name, found `{` +//~^ ERROR expected one of `!`, `(`, `)`, `,`, `?`, `for`, lifetime, or path, found `{` +//~| ERROR at least one trait is required for an object type + +fn foo4(_: &dyn <Drop + AsRef<str>>) {} //~ ERROR expected identifier, found `<` + +fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {} //~ ERROR invalid `dyn` keyword +//~^ ERROR only auto traits can be used as additional traits in a trait object + +fn main() {} diff --git a/src/test/ui/parser/trait-object-delimiters.stderr b/src/test/ui/parser/trait-object-delimiters.stderr new file mode 100644 index 00000000000..18b1b24122e --- /dev/null +++ b/src/test/ui/parser/trait-object-delimiters.stderr @@ -0,0 +1,77 @@ +error: ambiguous `+` in a type + --> $DIR/trait-object-delimiters.rs:3:13 + | +LL | fn foo1(_: &dyn Drop + AsRef<str>) {} + | ^^^^^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(dyn Drop + AsRef<str>)` + +error: incorrect braces around trait bounds + --> $DIR/trait-object-delimiters.rs:6:17 + | +LL | fn foo2(_: &dyn (Drop + AsRef<str>)) {} + | ^ ^ + | +help: remove the parentheses + | +LL | fn foo2(_: &dyn Drop + AsRef<str>) {} + | -- -- + +error: expected parameter name, found `{` + --> $DIR/trait-object-delimiters.rs:8:17 + | +LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {} + | ^ expected parameter name + +error: expected one of `!`, `(`, `)`, `,`, `?`, `for`, lifetime, or path, found `{` + --> $DIR/trait-object-delimiters.rs:8:17 + | +LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {} + | -^ expected one of 8 possible tokens + | | + | help: missing `,` + +error: expected identifier, found `<` + --> $DIR/trait-object-delimiters.rs:12:17 + | +LL | fn foo4(_: &dyn <Drop + AsRef<str>>) {} + | ^ expected identifier + +error: invalid `dyn` keyword + --> $DIR/trait-object-delimiters.rs:14:25 + | +LL | fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {} + | ^^^ help: remove this keyword + | + = help: `dyn` is only needed at the start of a trait `+`-separated list + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/trait-object-delimiters.rs:3:24 + | +LL | fn foo1(_: &dyn Drop + AsRef<str>) {} + | ---- ^^^^^^^^^^ additional non-auto trait + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as super-traits and using that trait here instead: `trait NewTrait: Drop + AsRef<str> {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0224]: at least one trait is required for an object type + --> $DIR/trait-object-delimiters.rs:8:13 + | +LL | fn foo3(_: &dyn {Drop + AsRef<str>}) {} + | ^^^ + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/trait-object-delimiters.rs:14:29 + | +LL | fn foo5(_: &(dyn Drop + dyn AsRef<str>)) {} + | ---- ^^^^^^^^^^ additional non-auto trait + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as super-traits and using that trait here instead: `trait NewTrait: Drop + AsRef<str> {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error: aborting due to 9 previous errors + +Some errors have detailed explanations: E0224, E0225. +For more information about an error, try `rustc --explain E0224`. |