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Gives a nicer error if the programmer uses the <=> operator. #89871

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Gives a nicer error if the programmer uses the <=> operator. #89871

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480edb1
Add an error for C++'s <=>
moonheart08 Oct 14, 2021
4f1cb6e
Tests for spaceship operator
moonheart08 Oct 14, 2021
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19 changes: 19 additions & 0 deletions compiler/rustc_parse/src/parser/expr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -213,6 +213,25 @@ impl<'a> Parser<'a> {
}
}

if op.node == AssocOp::LessEqual
&& self.token.kind == token::Gt
&& self.prev_token.span.hi() == self.token.span.lo()
{
// Look for C++'s `<=>`
let sp = op.span.to(self.token.span);
self.struct_span_err(sp, &format!("invalid comparison operator `<=>`"))
.span_suggestion_short(
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It makes no sense to suggest that the spaceship operator be replaced with itself. Instead, use span_label.

Suggested change
.span_suggestion_short(
.span_label(

sp,
&format!(
"`<=>` is not a valid comparison operator, use std::cmp::Ordering"
),
"<=>".to_string(),
Applicability::Unspecified,
)
.emit();
self.bump();
}

if (op.node == AssocOp::Equal || op.node == AssocOp::NotEqual)
&& self.token.kind == token::Eq
&& self.prev_token.span.hi() == self.token.span.lo()
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4 changes: 4 additions & 0 deletions src/test/ui/spaceship-operator.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
fn main() {
println!("{}", 1 <=> 2);
//~^ERROR invalid comparison operator `<=>`
}
8 changes: 8 additions & 0 deletions src/test/ui/spaceship-operator.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
error: invalid comparison operator `<=>`
--> $DIR/spaceship-operator.rs:2:22
|
LL | println!("{}", 1 <=> 2);
| ^^^ help: `<=>` is not a valid comparison operator, use std::cmp::Ordering

error: aborting due to previous error