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add trait aliases to AST

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This commit is contained in:
Alex Burka 2017-10-02 12:27:45 +00:00 • committed by Alex Burka
parent 8624ea5117
commit d4a28268cc
8 changed files with 134 additions and 14 deletions
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39
src/libsyntax/parse/parser.rs
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@ -5182,7 +5182,7 @@ impl<'a> Parser<'a> {
}
}
/// Parse trait Foo { ... }
/// Parse `trait Foo { ... }` or `trait Foo = Bar;`
fn parse_item_trait(&mut self, is_auto: IsAuto, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
let ident = self.parse_ident()?;
let mut tps = self.parse_generics()?;
@ -5194,23 +5194,34 @@ impl<'a> Parser<'a> {
Vec::new()
};
tps.where_clause = self.parse_where_clause()?;
self.expect(&token::OpenDelim(token::Brace))?;
let mut trait_items = vec![];
while !self.eat(&token::CloseDelim(token::Brace)) {
let mut at_end = false;
match self.parse_trait_item(&mut at_end) {
Ok(item) => trait_items.push(item),
Err(mut e) => {
e.emit();
if !at_end {
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
if self.eat(&token::Eq) {
// it's a trait alias
let bounds = self.parse_ty_param_bounds()?;
tps.where_clause = self.parse_where_clause()?;
self.expect(&token::Semi)?;
if unsafety != Unsafety::Normal {
self.span_err(self.prev_span, "trait aliases cannot be unsafe");
}
Ok((ident, ItemKind::TraitAlias(tps, bounds), None))
} else {
// it's a normal trait
tps.where_clause = self.parse_where_clause()?;
self.expect(&token::OpenDelim(token::Brace))?;
let mut trait_items = vec![];
while !self.eat(&token::CloseDelim(token::Brace)) {
let mut at_end = false;
match self.parse_trait_item(&mut at_end) {
Ok(item) => trait_items.push(item),
Err(mut e) => {
e.emit();
if !at_end {
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
}
}
}
}
Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
}
Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
}
/// Parses items implementations variants