diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs index ef6c9cc344ce..8c02092fd678 100644 --- a/compiler/rustc_parse/src/parser/generics.rs +++ b/compiler/rustc_parse/src/parser/generics.rs @@ -204,9 +204,11 @@ pub(crate) fn recover_const_param_with_mistyped_const( pub(super) fn parse_generic_params(&mut self) -> PResult<'a, ThinVec> { let mut params = ThinVec::new(); let mut done = false; + let prev = self.parsing_generics; + self.parsing_generics = true; while !done { let attrs = self.parse_outer_attributes()?; - let param = self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| { + let param = match self.collect_tokens(None, attrs, ForceCollect::No, |this, attrs| { if this.eat_keyword_noexpect(kw::SelfUpper) { // `Self` as a generic param is invalid. Here we emit the diagnostic and continue parsing // as if `Self` never existed. @@ -288,7 +290,13 @@ pub(super) fn parse_generic_params(&mut self) -> PResult<'a, ThinVec param, + Err(err) => { + self.parsing_generics = prev; + return Err(err); + } + }; if let Some(param) = param { params.push(param); @@ -296,6 +304,7 @@ pub(super) fn parse_generic_params(&mut self) -> PResult<'a, ThinVec { /// See the comments in the `parse_path_segment` function for more details. unmatched_angle_bracket_count: u16, angle_bracket_nesting: u16, + /// Keep track of when we're within `<...>` for proper error recovery. + parsing_generics: bool = false, last_unexpected_token_span: Option, /// If present, this `Parser` is not parsing Rust code but rather a macro call. @@ -372,6 +374,7 @@ pub fn new( }, current_closure: None, recovery: Recovery::Allowed, + .. }; // Make parser point to the first token. diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs index 0185c51c5c56..380b6a214846 100644 --- a/compiler/rustc_parse/src/parser/ty.rs +++ b/compiler/rustc_parse/src/parser/ty.rs @@ -1488,14 +1488,44 @@ fn recover_fn_trait_with_lifetime_params( return Ok(()); } + let snapshot = if self.parsing_generics { + // The snapshot is only relevant if we're parsing the generics of an `fn` to avoid + // incorrect recovery. + Some(self.create_snapshot_for_diagnostic()) + } else { + None + }; // 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(&mode)?.into_iter().map(|input| input.ty).collect(); + let params = match self.parse_fn_params(&mode) { + Ok(params) => params, + Err(err) => { + if let Some(snapshot) = snapshot { + self.restore_snapshot(snapshot); + err.cancel(); + return Ok(()); + } else { + return Err(err); + } + } + }; + let inputs: ThinVec<_> = params.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 output = match self.parse_ret_ty(AllowPlus::No, RecoverQPath::No, RecoverReturnSign::No) + { + Ok(output) => output, + Err(err) => { + if let Some(snapshot) = snapshot { + self.restore_snapshot(snapshot); + err.cancel(); + return Ok(()); + } else { + return Err(err); + } + } + }; let args = ast::ParenthesizedArgs { span: fn_path_segment.span().to(self.prev_token.span), inputs, @@ -1503,6 +1533,17 @@ fn recover_fn_trait_with_lifetime_params( output, } .into(); + + if let Some(snapshot) = snapshot + && ![token::Comma, token::Gt, token::Plus].contains(&self.token.kind) + { + // We would expect another bound or the end of type params by now. Most likely we've + // encountered a `(` *not* representing `Trait()`, but rather the start of the `fn`'s + // argument list where the generic param list wasn't properly closed. + self.restore_snapshot(snapshot); + return Ok(()); + } + *fn_path_segment = ast::PathSegment { ident: fn_path_segment.ident, args: Some(args), diff --git a/tests/ui/parser/missing-closing-generics-bracket.fixed b/tests/ui/parser/missing-closing-generics-bracket.fixed new file mode 100644 index 000000000000..3166887fa8c3 --- /dev/null +++ b/tests/ui/parser/missing-closing-generics-bracket.fixed @@ -0,0 +1,10 @@ +// Issue #141436 +//@ run-rustfix +#![allow(dead_code)] + +trait Trait<'a> {} + +fn foo>() {} +//~^ ERROR expected one of + +fn main() {} diff --git a/tests/ui/parser/missing-closing-generics-bracket.rs b/tests/ui/parser/missing-closing-generics-bracket.rs new file mode 100644 index 000000000000..9424e3467246 --- /dev/null +++ b/tests/ui/parser/missing-closing-generics-bracket.rs @@ -0,0 +1,10 @@ +// Issue #141436 +//@ run-rustfix +#![allow(dead_code)] + +trait Trait<'a> {} + +fn foo() {} +//~^ ERROR expected one of + +fn main() {} diff --git a/tests/ui/parser/missing-closing-generics-bracket.stderr b/tests/ui/parser/missing-closing-generics-bracket.stderr new file mode 100644 index 000000000000..c4287301c595 --- /dev/null +++ b/tests/ui/parser/missing-closing-generics-bracket.stderr @@ -0,0 +1,13 @@ +error: expected one of `+`, `,`, `::`, `=`, or `>`, found `(` + --> $DIR/missing-closing-generics-bracket.rs:7:25 + | +LL | fn foo() {} + | ^ expected one of `+`, `,`, `::`, `=`, or `>` + | +help: you might have meant to end the type parameters here + | +LL | fn foo>() {} + | + + +error: aborting due to 1 previous error +