bjoernager/rust
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Parse auto traits the same as traits.

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This moves the well formedness checks to the AST validation pass. Tests
were adjusted.

The auto keyword should be back-compat now.
This commit is contained in:
leonardo.yvens 2017-10-15 16:03:03 -02:00
parent 9d181ac2de
commit 97de8cae6e
7 changed files with 83 additions and 110 deletions
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81
src/libsyntax/parse/parser.rs
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@ -16,7 +16,6 @@ use ast::{Mod, Arg, Arm, Attribute, BindingMode, TraitItemKind};
use ast::Block;
use ast::{BlockCheckMode, CaptureBy};
use ast::{Constness, Crate};
use ast::Generics;
use ast::Defaultness;
use ast::EnumDef;
use ast::{Expr, ExprKind, RangeLimits};
@ -3874,6 +3873,16 @@ impl<'a> Parser<'a> {
self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
}
fn eat_auto_trait(&mut self) -> bool {
if self.token.is_keyword(keywords::Auto)
&& self.look_ahead(1, |t| t.is_keyword(keywords::Trait))
{
self.eat_keyword(keywords::Auto) && self.eat_keyword(keywords::Trait)
} else {
false
}
}
fn is_defaultness(&self) -> bool {
// `pub` is included for better error messages
self.token.is_keyword(keywords::Default) &&
@ -5052,7 +5061,7 @@ impl<'a> Parser<'a> {
}
/// Parse trait Foo { ... }
fn parse_item_trait(&mut self, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
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()?;
@ -5079,17 +5088,7 @@ impl<'a> Parser<'a> {
}
}
}
Ok((ident, ItemKind::Trait(IsAuto::No, unsafety, tps, bounds, trait_items), None))
}
fn parse_item_auto_trait(&mut self, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
let ident = self.parse_ident()?;
self.expect(&token::OpenDelim(token::Brace))?;
self.expect(&token::CloseDelim(token::Brace))?;
// Auto traits cannot have generics, super traits nor contain items.
Ok((ident,
ItemKind::Trait(IsAuto::Yes, unsafety, Generics::default(), Vec::new(), Vec::new()),
None))
Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None))
}
/// Parses items implementations variants
@ -5999,44 +5998,19 @@ impl<'a> Parser<'a> {
return Ok(Some(item));
}
if self.check_keyword(keywords::Unsafe) &&
self.look_ahead(1, |t| t.is_keyword(keywords::Trait))
(self.look_ahead(1, |t| t.is_keyword(keywords::Trait)) ||
self.look_ahead(1, |t| t.is_keyword(keywords::Auto)))
{
// UNSAFE TRAIT ITEM
self.expect_keyword(keywords::Unsafe)?;
self.expect_keyword(keywords::Trait)?;
let is_auto = if self.eat_keyword(keywords::Trait) {
IsAuto::No
} else {
self.eat_auto_trait();
IsAuto::Yes
};
let (ident, item_, extra_attrs) =
self.parse_item_trait(ast::Unsafety::Unsafe)?;
let prev_span = self.prev_span;
let item = self.mk_item(lo.to(prev_span),
ident,
item_,
visibility,
maybe_append(attrs, extra_attrs));
return Ok(Some(item));
}
if self.eat_keyword(keywords::Auto) {
self.expect_keyword(keywords::Trait)?;
// AUTO TRAIT ITEM
let (ident,
item_,
extra_attrs) = self.parse_item_auto_trait(ast::Unsafety::Normal)?;
let prev_span = self.prev_span;
let item = self.mk_item(lo.to(prev_span),
ident,
item_,
visibility,
maybe_append(attrs, extra_attrs));
return Ok(Some(item));
}
if self.check_keyword(keywords::Unsafe) &&
self.look_ahead(1, |t| t.is_keyword(keywords::Auto)) {
self.expect_keyword(keywords::Unsafe)?;
self.expect_keyword(keywords::Auto)?;
self.expect_keyword(keywords::Trait)?;
// UNSAFE AUTO TRAIT ITEM
let (ident,
item_,
extra_attrs) = self.parse_item_auto_trait(ast::Unsafety::Unsafe)?;
self.parse_item_trait(is_auto, ast::Unsafety::Unsafe)?;
let prev_span = self.prev_span;
let item = self.mk_item(lo.to(prev_span),
ident,
@ -6139,10 +6113,19 @@ impl<'a> Parser<'a> {
maybe_append(attrs, extra_attrs));
return Ok(Some(item));
}
if self.eat_keyword(keywords::Trait) {
if self.check_keyword(keywords::Trait)
|| (self.check_keyword(keywords::Auto)
&& self.look_ahead(1, |t| t.is_keyword(keywords::Trait)))
{
let is_auto = if self.eat_keyword(keywords::Trait) {
IsAuto::No
} else {
self.eat_auto_trait();
IsAuto::Yes
};
// TRAIT ITEM
let (ident, item_, extra_attrs) =
self.parse_item_trait(ast::Unsafety::Normal)?;
self.parse_item_trait(is_auto, ast::Unsafety::Normal)?;
let prev_span = self.prev_span;
let item = self.mk_item(lo.to(prev_span),
ident,