&mut self,
cast_expr: P<Expr>,
) -> PResult<'a, P<Expr>> {
+ let span = cast_expr.span;
+ let maybe_ascription_span = if let ExprKind::Type(ascripted_expr, _) = &cast_expr.kind {
+ Some(ascripted_expr.span.shrink_to_hi().with_hi(span.hi()))
+ } else {
+ None
+ };
+
// Save the memory location of expr before parsing any following postfix operators.
// This will be compared with the memory location of the output expression.
// If they different we can assume we parsed another expression because the existing expression is not reallocated.
let addr_before = &*cast_expr as *const _ as usize;
- let span = cast_expr.span;
let with_postfix = self.parse_dot_or_call_expr_with_(cast_expr, span)?;
let changed = addr_before != &*with_postfix as *const _ as usize;
}
);
let mut err = self.struct_span_err(span, &msg);
- // If type ascription is "likely an error", the user will already be getting a useful
- // help message, and doesn't need a second.
- if self.last_type_ascription.map_or(false, |last_ascription| last_ascription.1) {
- self.maybe_annotate_with_ascription(&mut err, false);
- } else {
+
+ let suggest_parens = |err: &mut DiagnosticBuilder<'_, _>| {
let suggestions = vec![
(span.shrink_to_lo(), "(".to_string()),
(span.shrink_to_hi(), ")".to_string()),
suggestions,
Applicability::MachineApplicable,
);
+ };
+
+ // If type ascription is "likely an error", the user will already be getting a useful
+ // help message, and doesn't need a second.
+ if self.last_type_ascription.map_or(false, |last_ascription| last_ascription.1) {
+ self.maybe_annotate_with_ascription(&mut err, false);
+ } else if let Some(ascription_span) = maybe_ascription_span {
+ let is_nightly = self.sess.unstable_features.is_nightly_build();
+ if is_nightly {
+ suggest_parens(&mut err);
+ }
+ err.span_suggestion(
+ ascription_span,
+ &format!(
+ "{}remove the type ascription",
+ if is_nightly { "alternatively, " } else { "" }
+ ),
+ String::new(),
+ if is_nightly {
+ Applicability::MaybeIncorrect
+ } else {
+ Applicability::MachineApplicable
+ },
+ );
+ } else {
+ suggest_parens(&mut err);
}
err.emit();
};