diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index 61396ee0d4aec..018eddea4b06b 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -1448,8 +1448,19 @@ impl<'a> Parser<'a> { } fn parse_expr_path_start(&mut self) -> PResult<'a, P> { + let maybe_eq_tok = self.prev_token.clone(); let (qself, path) = if self.eat_lt() { - let (qself, path) = self.parse_qpath(PathStyle::Expr)?; + let lt_span = self.prev_token.span; + let (qself, path) = self.parse_qpath(PathStyle::Expr).map_err(|mut err| { + // Suggests using '<=' if there is an error parsing qpath when the previous token + // is an '=' token. Only emits suggestion if the '<' token and '=' token are + // directly adjacent (i.e. '=<') + if maybe_eq_tok.kind == TokenKind::Eq && maybe_eq_tok.span.hi() == lt_span.lo() { + let eq_lt = maybe_eq_tok.span.to(lt_span); + err.span_suggestion(eq_lt, "did you mean", "<=", Applicability::Unspecified); + } + err + })?; (Some(qself), path) } else { (None, self.parse_path(PathStyle::Expr)?) diff --git a/tests/ui/parser/eq-less-to-less-eq.rs b/tests/ui/parser/eq-less-to-less-eq.rs new file mode 100644 index 0000000000000..23c6c59d7a62b --- /dev/null +++ b/tests/ui/parser/eq-less-to-less-eq.rs @@ -0,0 +1,33 @@ +fn foo() { + let a = 0; + let b = 4; + if a =< b { //~ERROR + println!("yay!"); + } +} + +fn bar() { + let a = 0; + let b = 4; + if a = ::abs(-4) { //~ERROR: mismatched types + println!("yay!"); + } +} + +fn main() {} diff --git a/tests/ui/parser/eq-less-to-less-eq.stderr b/tests/ui/parser/eq-less-to-less-eq.stderr new file mode 100644 index 0000000000000..4717d8287ff7b --- /dev/null +++ b/tests/ui/parser/eq-less-to-less-eq.stderr @@ -0,0 +1,34 @@ +error: expected one of `!`, `(`, `+`, `::`, `<`, `>`, or `as`, found `{` + --> $DIR/eq-less-to-less-eq.rs:4:15 + | +LL | if a =< b { + | -- ^ expected one of 7 possible tokens + | | + | help: did you mean: `<=` + +error: expected one of `!`, `(`, `+`, `::`, `<`, `>`, or `as`, found `{` + --> $DIR/eq-less-to-less-eq.rs:12:15 + | +LL | if a = `, or `as`, found `{` + --> $DIR/eq-less-to-less-eq.rs:20:16 + | +LL | if a = < b { + | ^ expected one of 7 possible tokens + +error[E0308]: mismatched types + --> $DIR/eq-less-to-less-eq.rs:28:8 + | +LL | if a =< i32>::abs(-4) { + | ^^^^^^^^^^^^^^^^^^ expected `bool`, found `()` + | +help: you might have meant to compare for equality + | +LL | if a ==< i32>::abs(-4) { + | + + +error: aborting due to 4 previous errors + +For more information about this error, try `rustc --explain E0308`.