diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index 17d1e200b41..dcc3059a7f4 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -1882,7 +1882,16 @@ fn recover_after_dot(&mut self) -> Option { if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) = next_token.kind { - if self.token.span.hi() == next_token.span.lo() { + // If this integer looks like a float, then recover as such. + // + // We will never encounter the exponent part of a floating + // point literal here, since there's no use of the exponent + // syntax that also constitutes a valid integer, so we need + // not check for that. + if suffix.map_or(true, |s| s == sym::f32 || s == sym::f64) + && symbol.as_str().chars().all(|c| c.is_numeric() || c == '_') + && self.token.span.hi() == next_token.span.lo() + { let s = String::from("0.") + symbol.as_str(); let kind = TokenKind::lit(token::Float, Symbol::intern(&s), suffix); return Some(Token::new(kind, self.token.span.to(next_token.span))); diff --git a/tests/ui/suggestions/recover-invalid-float-invalid.rs b/tests/ui/suggestions/recover-invalid-float-invalid.rs new file mode 100644 index 00000000000..79430d8c051 --- /dev/null +++ b/tests/ui/suggestions/recover-invalid-float-invalid.rs @@ -0,0 +1,24 @@ +// Check that suggestions to add a zero to integers with a preceding dot only appear when the change +// will result in a valid floating point literal. + +fn main() {} + +fn a() { + _ = .3u32; + //~^ ERROR expected expression, found `.` +} + +fn b() { + _ = .0b0; + //~^ ERROR expected expression, found `.` +} + +fn c() { + _ = .0o07; + //~^ ERROR expected expression, found `.` +} + +fn d() { + _ = .0x0ABC; + //~^ ERROR expected expression, found `.` +} diff --git a/tests/ui/suggestions/recover-invalid-float-invalid.stderr b/tests/ui/suggestions/recover-invalid-float-invalid.stderr new file mode 100644 index 00000000000..5764afc1a21 --- /dev/null +++ b/tests/ui/suggestions/recover-invalid-float-invalid.stderr @@ -0,0 +1,26 @@ +error: expected expression, found `.` + --> $DIR/recover-invalid-float-invalid.rs:7:9 + | +LL | _ = .3u32; + | ^ expected expression + +error: expected expression, found `.` + --> $DIR/recover-invalid-float-invalid.rs:12:9 + | +LL | _ = .0b0; + | ^ expected expression + +error: expected expression, found `.` + --> $DIR/recover-invalid-float-invalid.rs:17:9 + | +LL | _ = .0o07; + | ^ expected expression + +error: expected expression, found `.` + --> $DIR/recover-invalid-float-invalid.rs:22:9 + | +LL | _ = .0x0ABC; + | ^ expected expression + +error: aborting due to 4 previous errors +