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Fix issue with single question mark or paren

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This commit is contained in:
Vadim Petrochenkov 2017-04-21 00:19:06 +03:00
parent e038f58105
commit 6e75def7db
3 changed files with 44 additions and 25 deletions
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51
src/libsyntax/parse/parser.rs
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@ -4086,32 +4086,37 @@ impl<'a> Parser<'a> {
fn parse_ty_param_bounds_common(&mut self, allow_plus: bool) -> PResult<'a, TyParamBounds> {
let mut bounds = Vec::new();
loop {
let has_parens = self.eat(&token::OpenDelim(token::Paren));
let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
if self.check_lifetime() {
if let Some(question_span) = question {
self.span_err(question_span,
"`?` may only modify trait bounds, not lifetime bounds");
}
bounds.push(RegionTyParamBound(self.expect_lifetime()));
if has_parens {
self.expect(&token::CloseDelim(token::Paren))?;
self.span_err(self.prev_span,
"parenthesized lifetime bounds are not supported");
}
} else if self.check_keyword(keywords::For) || self.check_path() {
let lo = self.span;
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
let path = self.parse_path(PathStyle::Type)?;
let poly_trait = PolyTraitRef::new(lifetime_defs, path, lo.to(self.prev_span));
let modifier = if question.is_some() {
TraitBoundModifier::Maybe
let is_bound_start = self.check_path() || self.check_lifetime() ||
self.check(&token::Question) ||
self.check_keyword(keywords::For) ||
self.check(&token::OpenDelim(token::Paren));
if is_bound_start {
let has_parens = self.eat(&token::OpenDelim(token::Paren));
let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
if self.token.is_lifetime() {
if let Some(question_span) = question {
self.span_err(question_span,
"`?` may only modify trait bounds, not lifetime bounds");
}
bounds.push(RegionTyParamBound(self.expect_lifetime()));
} else {
TraitBoundModifier::None
};
bounds.push(TraitTyParamBound(poly_trait, modifier));
let lo = self.span;
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
let path = self.parse_path(PathStyle::Type)?;
let poly_trait = PolyTraitRef::new(lifetime_defs, path, lo.to(self.prev_span));
let modifier = if question.is_some() {
TraitBoundModifier::Maybe
} else {
TraitBoundModifier::None
};
bounds.push(TraitTyParamBound(poly_trait, modifier));
}
if has_parens {
self.expect(&token::CloseDelim(token::Paren))?;
if let Some(&RegionTyParamBound(..)) = bounds.last() {
self.span_err(self.prev_span,
"parenthesized lifetime bounds are not supported");
}
}
} else {
break