}
}
+ fn look_ahead_type_ascription_as_field(&mut self) -> bool {
+ self.look_ahead(1, |t| t.is_ident())
+ && self.look_ahead(2, |t| t == &token::Colon)
+ && self.look_ahead(3, |t| t.can_begin_expr())
+ }
+
fn parse_dot_suffix_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
match self.token.uninterpolate().kind {
token::Ident(..) => self.parse_dot_suffix(base, lo),
/// Parse a function call expression, `expr(...)`.
fn parse_fn_call_expr(&mut self, lo: Span, fun: P<Expr>) -> P<Expr> {
- let seq = self.parse_paren_expr_seq().map(|args| {
+ let snapshot = if self.token.kind == token::OpenDelim(token::Paren)
+ && self.look_ahead_type_ascription_as_field()
+ {
+ Some((self.clone(), fun.kind.clone()))
+ } else {
+ None
+ };
+ let open_paren = self.token.span;
+
+ let mut seq = self.parse_paren_expr_seq().map(|args| {
self.mk_expr(lo.to(self.prev_token.span), self.mk_call(fun, args), AttrVec::new())
});
+ if let Some(expr) =
+ self.maybe_recover_struct_lit_bad_delims(lo, open_paren, &mut seq, snapshot)
+ {
+ return expr;
+ }
self.recover_seq_parse_error(token::Paren, lo, seq)
}
+ /// If we encounter a parser state that looks like the user has written a `struct` literal with
+ /// parentheses instead of braces, recover the parser state and provide suggestions.
+ fn maybe_recover_struct_lit_bad_delims(
+ &mut self,
+ lo: Span,
+ open_paren: Span,
+ seq: &mut PResult<'a, P<Expr>>,
+ snapshot: Option<(Self, ExprKind)>,
+ ) -> Option<P<Expr>> {
+ match (seq.as_mut(), snapshot) {
+ (Err(ref mut err), Some((mut snapshot, ExprKind::Path(None, path)))) => {
+ let name = pprust::path_to_string(&path);
+ snapshot.bump(); // `(`
+ match snapshot.parse_struct_fields(path.clone(), false, token::Paren) {
+ Ok((fields, ..)) if snapshot.eat(&token::CloseDelim(token::Paren)) => {
+ // We have are certain we have `Enum::Foo(a: 3, b: 4)`, suggest
+ // `Enum::Foo { a: 3, b: 4 }` or `Enum::Foo(3, 4)`.
+ *self = snapshot;
+ let close_paren = self.prev_token.span;
+ let span = lo.to(self.prev_token.span);
+ err.cancel();
+ self.struct_span_err(
+ span,
+ "invalid `struct` delimiters or `fn` call arguments",
+ )
+ .multipart_suggestion(
+ &format!("if `{}` is a struct, use braces as delimiters", name),
+ vec![(open_paren, " { ".to_string()), (close_paren, " }".to_string())],
+ Applicability::MaybeIncorrect,
+ )
+ .multipart_suggestion(
+ &format!("if `{}` is a function, use the arguments directly", name),
+ fields
+ .into_iter()
+ .map(|field| (field.span.until(field.expr.span), String::new()))
+ .collect(),
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ return Some(self.mk_expr_err(span));
+ }
+ Ok(_) => {}
+ Err(mut err) => err.emit(),
+ }
+ }
+ _ => {}
+ }
+ None
+ }
+
/// Parse an indexing expression `expr[...]`.
fn parse_index_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
self.bump(); // `[`
.emit();
}
- /// Precondition: already parsed the '{'.
- pub(super) fn parse_struct_expr(
+ pub(super) fn parse_struct_fields(
&mut self,
- qself: Option<ast::QSelf>,
pth: ast::Path,
- attrs: AttrVec,
recover: bool,
- ) -> PResult<'a, P<Expr>> {
+ close_delim: token::DelimToken,
+ ) -> PResult<'a, (Vec<ExprField>, ast::StructRest, bool)> {
let mut fields = Vec::new();
let mut base = ast::StructRest::None;
let mut recover_async = false;
e.note("for more on editions, read https://doc.rust-lang.org/edition-guide");
};
- while self.token != token::CloseDelim(token::Brace) {
+ while self.token != token::CloseDelim(close_delim) {
if self.eat(&token::DotDot) {
let exp_span = self.prev_token.span;
// We permit `.. }` on the left-hand side of a destructuring assignment.
- if self.check(&token::CloseDelim(token::Brace)) {
+ if self.check(&token::CloseDelim(close_delim)) {
self.sess.gated_spans.gate(sym::destructuring_assignment, self.prev_token.span);
base = ast::StructRest::Rest(self.prev_token.span.shrink_to_hi());
break;
}
};
- match self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)]) {
+ match self.expect_one_of(&[token::Comma], &[token::CloseDelim(close_delim)]) {
Ok(_) => {
if let Some(f) = parsed_field.or(recovery_field) {
// Only include the field if there's no parse error for the field name.
}
}
}
+ Ok((fields, base, recover_async))
+ }
- let span = pth.span.to(self.token.span);
+ /// Precondition: already parsed the '{'.
+ pub(super) fn parse_struct_expr(
+ &mut self,
+ qself: Option<ast::QSelf>,
+ pth: ast::Path,
+ attrs: AttrVec,
+ recover: bool,
+ ) -> PResult<'a, P<Expr>> {
+ let lo = pth.span;
+ let (fields, base, recover_async) =
+ self.parse_struct_fields(pth.clone(), recover, token::Brace)?;
+ let span = lo.to(self.token.span);
self.expect(&token::CloseDelim(token::Brace))?;
let expr = if recover_async {
ExprKind::Err
projects / rust.git / blobdiff