diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libsyntax/parse/diagnostics.rs | 100 | ||||
| -rw-r--r-- | src/libsyntax/parse/parser/expr.rs | 4 | ||||
| -rw-r--r-- | src/test/ui/did_you_mean/issue-40396.stderr | 16 | ||||
| -rw-r--r-- | src/test/ui/parser/require-parens-for-chained-comparison.rs | 5 | ||||
| -rw-r--r-- | src/test/ui/parser/require-parens-for-chained-comparison.stderr | 23 |
5 files changed, 121 insertions, 27 deletions
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs index e8d7b7663ed..0e3d873b252 100644 --- a/src/libsyntax/parse/diagnostics.rs +++ b/src/libsyntax/parse/diagnostics.rs @@ -543,16 +543,25 @@ impl<'a> Parser<'a> { } /// Produces an error if comparison operators are chained (RFC #558). - /// We only need to check the LHS, not the RHS, because all comparison ops - /// have same precedence and are left-associative. - crate fn check_no_chained_comparison(&self, lhs: &Expr, outer_op: &AssocOp) -> PResult<'a, ()> { - debug_assert!(outer_op.is_comparison(), - "check_no_chained_comparison: {:?} is not comparison", - outer_op); + /// We only need to check the LHS, not the RHS, because all comparison ops have same + /// precedence and are left-associative. + /// + /// This can also be hit if someone incorrectly writes `foo<bar>()` when they should have used + /// the turbofish syntax. We attempt some heuristic recovery if that is the case. + crate fn check_no_chained_comparison( + &mut self, + lhs: &Expr, + outer_op: &AssocOp, + ) -> PResult<'a, Option<P<Expr>>> { + debug_assert!( + outer_op.is_comparison(), + "check_no_chained_comparison: {:?} is not comparison", + outer_op, + ); match lhs.kind { ExprKind::Binary(op, _, _) if op.node.is_comparison() => { // Respan to include both operators. - let op_span = op.span.to(self.token.span); + let op_span = op.span.to(self.prev_span); let mut err = self.struct_span_err( op_span, "chained comparison operators require parentheses", @@ -561,17 +570,84 @@ impl<'a> Parser<'a> { *outer_op == AssocOp::Less || // Include `<` to provide this recommendation *outer_op == AssocOp::Greater // even in a case like the following: { // Foo<Bar<Baz<Qux, ()>>> - err.help( - "use `::<...>` instead of `<...>` if you meant to specify type arguments"); - err.help("or use `(...)` if you meant to specify fn arguments"); - // These cases cause too many knock-down errors, bail out (#61329). + let msg = "use `::<...>` instead of `<...>` if you meant to specify type \ + arguments"; + if *outer_op == AssocOp::Less { + // if self.look_ahead(1, |t| t.kind == token::Lt || t.kind == token::ModSep) { + let snapshot = self.clone(); + self.bump(); + // So far we have parsed `foo<bar<` + let mut acc = 1; + while acc > 0 { + match &self.token.kind { + token::Lt => { + acc += 1; + } + token::Gt => { + acc -= 1; + } + token::BinOp(token::Shr) => { + acc -= 2; + } + token::Eof => { + break; + } + _ => {} + } + self.bump(); + } + if self.token.kind != token::OpenDelim(token::Paren) { + mem::replace(self, snapshot.clone()); + } + } + if self.token.kind == token::OpenDelim(token::Paren) { + err.span_suggestion( + op_span.shrink_to_lo(), + msg, + "::".to_string(), + Applicability::MaybeIncorrect, + ); + let snapshot = self.clone(); + self.bump(); + let mut acc = 1; + while acc > 0 { + match &self.token.kind { + token::OpenDelim(token::Paren) => { + acc += 1; + } + token::CloseDelim(token::Paren) => { + acc -= 1; + } + token::Eof => { + break; + } + _ => {} + } + self.bump(); + } + if self.token.kind == token::Eof { + mem::replace(self, snapshot); + return Err(err); + } else { + err.emit(); + return Ok(Some(self.mk_expr( + lhs.span.to(self.prev_span), + ExprKind::Err, + ThinVec::new(), + ))); + } + } else { + err.help(msg); + err.help("or use `(...)` if you meant to specify fn arguments"); + // These cases cause too many knock-down errors, bail out (#61329). + } return Err(err); } err.emit(); } _ => {} } - Ok(()) + Ok(None) } crate fn maybe_report_ambiguous_plus( diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs index 23674ad589d..b459782d237 100644 --- a/src/libsyntax/parse/parser/expr.rs +++ b/src/libsyntax/parse/parser/expr.rs @@ -238,7 +238,9 @@ impl<'a> Parser<'a> { self.bump(); if op.is_comparison() { - self.check_no_chained_comparison(&lhs, &op)?; + if let Some(expr) = self.check_no_chained_comparison(&lhs, &op)? { + return Ok(expr); + } } // Special cases: if op == AssocOp::As { diff --git a/src/test/ui/did_you_mean/issue-40396.stderr b/src/test/ui/did_you_mean/issue-40396.stderr index 7a08fda27e3..d0448cc265c 100644 --- a/src/test/ui/did_you_mean/issue-40396.stderr +++ b/src/test/ui/did_you_mean/issue-40396.stderr @@ -2,16 +2,17 @@ error: chained comparison operators require parentheses --> $DIR/issue-40396.rs:2:20 | LL | (0..13).collect<Vec<i32>>(); - | ^^^^^^^^ + | ^^^^^ +help: use `::<...>` instead of `<...>` if you meant to specify type arguments | - = help: use `::<...>` instead of `<...>` if you meant to specify type arguments - = help: or use `(...)` if you meant to specify fn arguments +LL | (0..13).collect::<Vec<i32>>(); + | ^^ error: chained comparison operators require parentheses --> $DIR/issue-40396.rs:7:8 | LL | Vec<i32>::new(); - | ^^^^^^^ + | ^^^^^ | = help: use `::<...>` instead of `<...>` if you meant to specify type arguments = help: or use `(...)` if you meant to specify fn arguments @@ -20,10 +21,11 @@ error: chained comparison operators require parentheses --> $DIR/issue-40396.rs:12:20 | LL | (0..13).collect<Vec<i32>(); - | ^^^^^^^^ + | ^^^^^ +help: use `::<...>` instead of `<...>` if you meant to specify type arguments | - = help: use `::<...>` instead of `<...>` if you meant to specify type arguments - = help: or use `(...)` if you meant to specify fn arguments +LL | (0..13).collect::<Vec<i32>(); + | ^^ error: aborting due to 3 previous errors diff --git a/src/test/ui/parser/require-parens-for-chained-comparison.rs b/src/test/ui/parser/require-parens-for-chained-comparison.rs index 3dcc0c8f3d4..11839938cb0 100644 --- a/src/test/ui/parser/require-parens-for-chained-comparison.rs +++ b/src/test/ui/parser/require-parens-for-chained-comparison.rs @@ -13,5 +13,8 @@ fn main() { f<X>(); //~^ ERROR chained comparison operators require parentheses //~| HELP: use `::<...>` instead of `<...>` - //~| HELP: or use `(...)` + + f<Result<Option<X>, Option<Option<X>>>(1, 2); + //~^ ERROR chained comparison operators require parentheses + //~| HELP: use `::<...>` instead of `<...>` } diff --git a/src/test/ui/parser/require-parens-for-chained-comparison.stderr b/src/test/ui/parser/require-parens-for-chained-comparison.stderr index e927f4c3248..02fb56a7f9b 100644 --- a/src/test/ui/parser/require-parens-for-chained-comparison.stderr +++ b/src/test/ui/parser/require-parens-for-chained-comparison.stderr @@ -2,22 +2,33 @@ error: chained comparison operators require parentheses --> $DIR/require-parens-for-chained-comparison.rs:5:11 | LL | false == false == false; - | ^^^^^^^^^^^^^^^^^ + | ^^^^^^^^^^^ error: chained comparison operators require parentheses --> $DIR/require-parens-for-chained-comparison.rs:8:11 | LL | false == 0 < 2; - | ^^^^^^^^ + | ^^^^^^ error: chained comparison operators require parentheses --> $DIR/require-parens-for-chained-comparison.rs:13:6 | LL | f<X>(); - | ^^^^ + | ^^^ +help: use `::<...>` instead of `<...>` if you meant to specify type arguments | - = help: use `::<...>` instead of `<...>` if you meant to specify type arguments - = help: or use `(...)` if you meant to specify fn arguments +LL | f::<X>(); + | ^^ + +error: chained comparison operators require parentheses + --> $DIR/require-parens-for-chained-comparison.rs:17:6 + | +LL | f<Result<Option<X>, Option<Option<X>>>(1, 2); + | ^^^^^^^^ +help: use `::<...>` instead of `<...>` if you meant to specify type arguments + | +LL | f::<Result<Option<X>, Option<Option<X>>>(1, 2); + | ^^ error[E0308]: mismatched types --> $DIR/require-parens-for-chained-comparison.rs:8:14 @@ -37,6 +48,6 @@ LL | false == 0 < 2; = note: expected type `bool` found type `{integer}` -error: aborting due to 5 previous errors +error: aborting due to 6 previous errors For more information about this error, try `rustc --explain E0308`. |