diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 1b28f3c97e8..9e5f85dc7dc 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -91,6 +91,18 @@ impl From
> for LhsExpr {
}
}
+#[derive(Debug)]
+enum DestructuredFloat {
+ /// 1e2
+ Single(Symbol, Span),
+ /// 1.
+ TrailingDot(Symbol, Span, Span),
+ /// 1.2 | 1.2e3
+ MiddleDot(Symbol, Span, Span, Symbol, Span),
+ /// Invalid
+ Error,
+}
+
impl<'a> Parser<'a> {
/// Parses an expression.
#[inline]
@@ -1013,13 +1025,8 @@ impl<'a> Parser<'a> {
// support pushing "future tokens" (would be also helpful to `break_and_eat`), or
// we should break everything including floats into more basic proc-macro style
// tokens in the lexer (probably preferable).
- fn parse_expr_tuple_field_access_float(
- &mut self,
- lo: Span,
- base: P,
- float: Symbol,
- suffix: Option,
- ) -> P {
+ // See also `TokenKind::break_two_token_op` which does similar splitting of `>>` into `>`.
+ fn break_up_float(&mut self, float: Symbol) -> DestructuredFloat {
#[derive(Debug)]
enum FloatComponent {
IdentLike(String),
@@ -1056,7 +1063,7 @@ impl<'a> Parser<'a> {
match &*components {
// 1e2
[IdentLike(i)] => {
- self.parse_expr_tuple_field_access(lo, base, Symbol::intern(&i), suffix, None)
+ DestructuredFloat::Single(Symbol::intern(&i), span)
}
// 1.
[IdentLike(i), Punct('.')] => {
@@ -1068,11 +1075,8 @@ impl<'a> Parser<'a> {
} else {
(span, span)
};
- assert!(suffix.is_none());
let symbol = Symbol::intern(&i);
- self.token = Token::new(token::Ident(symbol, false), ident_span);
- let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
- self.parse_expr_tuple_field_access(lo, base, symbol, None, Some(next_token))
+ DestructuredFloat::TrailingDot(symbol, ident_span, dot_span)
}
// 1.2 | 1.2e3
[IdentLike(i1), Punct('.'), IdentLike(i2)] => {
@@ -1088,16 +1092,8 @@ impl<'a> Parser<'a> {
(span, span, span)
};
let symbol1 = Symbol::intern(&i1);
- self.token = Token::new(token::Ident(symbol1, false), ident1_span);
- // This needs to be `Spacing::Alone` to prevent regressions.
- // See issue #76399 and PR #76285 for more details
- let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
- let base1 =
- self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
let symbol2 = Symbol::intern(&i2);
- let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
- self.bump_with((next_token2, self.token_spacing)); // `.`
- self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
+ DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span)
}
// 1e+ | 1e- (recovered)
[IdentLike(_), Punct('+' | '-')] |
@@ -1109,12 +1105,47 @@ impl<'a> Parser<'a> {
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-'), IdentLike(_)] => {
// See the FIXME about `TokenCursor` above.
self.error_unexpected_after_dot();
- base
+ DestructuredFloat::Error
}
_ => panic!("unexpected components in a float token: {:?}", components),
}
}
+ fn parse_expr_tuple_field_access_float(
+ &mut self,
+ lo: Span,
+ base: P,
+ float: Symbol,
+ suffix: Option,
+ ) -> P {
+ match self.break_up_float(float) {
+ // 1e2
+ DestructuredFloat::Single(sym, _sp) => {
+ self.parse_expr_tuple_field_access(lo, base, sym, suffix, None)
+ }
+ // 1.
+ DestructuredFloat::TrailingDot(sym, ident_span, dot_span) => {
+ assert!(suffix.is_none());
+ self.token = Token::new(token::Ident(sym, false), ident_span);
+ let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
+ self.parse_expr_tuple_field_access(lo, base, sym, None, Some(next_token))
+ }
+ // 1.2 | 1.2e3
+ DestructuredFloat::MiddleDot(symbol1, ident1_span, dot_span, symbol2, ident2_span) => {
+ self.token = Token::new(token::Ident(symbol1, false), ident1_span);
+ // This needs to be `Spacing::Alone` to prevent regressions.
+ // See issue #76399 and PR #76285 for more details
+ let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
+ let base1 =
+ self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
+ let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
+ self.bump_with((next_token2, self.token_spacing)); // `.`
+ self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
+ }
+ DestructuredFloat::Error => base,
+ }
+ }
+
fn parse_expr_tuple_field_access(
&mut self,
lo: Span,