bjoernager/rust
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syntax: reject trait Foo: Bar = Baz;.

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Add test for rejecting `trait A: B1 = B2;`.
Also test rejection of `trait A: = B;`.
This commit is contained in:
Mazdak Farrokhzad 2019-09-21 17:18:08 +02:00
parent 4a8c5b20c7
commit 2e64bb2d37
3 changed files with 40 additions and 13 deletions
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28
src/libsyntax/parse/parser/item.rs
View file

@ -211,7 +211,7 @@ impl<'a> Parser<'a> {
{
// UNSAFE TRAIT ITEM
self.bump(); // `unsafe`
let info = self.parse_item_trait(Unsafety::Unsafe)?;
let info = self.parse_item_trait(lo, Unsafety::Unsafe)?;
return self.mk_item_with_info(attrs, lo, vis, info);
}
@ -289,7 +289,7 @@ impl<'a> Parser<'a> {
&& self.is_keyword_ahead(1, &[kw::Trait]))
{
// TRAIT ITEM
let info = self.parse_item_trait(Unsafety::Normal)?;
let info = self.parse_item_trait(lo, Unsafety::Normal)?;
return self.mk_item_with_info(attrs, lo, vis, info);
}
@ -780,7 +780,7 @@ impl<'a> Parser<'a> {
}
/// Parses `auto? trait Foo { ... }` or `trait Foo = Bar;`.
fn parse_item_trait(&mut self, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
fn parse_item_trait(&mut self, lo: Span, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
// Parse optional `auto` prefix.
let is_auto = if self.eat_keyword(kw::Auto) {
IsAuto::Yes
@ -793,29 +793,41 @@ impl<'a> Parser<'a> {
let mut tps = self.parse_generics()?;
// Parse optional colon and supertrait bounds.
let bounds = if self.eat(&token::Colon) {
let had_colon = self.eat(&token::Colon);
let span_at_colon = self.prev_span;
let bounds = if had_colon {
self.parse_generic_bounds(Some(self.prev_span))?
} else {
Vec::new()
};
let span_before_eq = self.prev_span;
if self.eat(&token::Eq) {
// It's a trait alias.
if had_colon {
let span = span_at_colon.to(span_before_eq);
self.struct_span_err(span, "bounds are not allowed on trait aliases")
.emit();
}
let bounds = self.parse_generic_bounds(None)?;
tps.where_clause = self.parse_where_clause()?;
self.expect(&token::Semi)?;
let whole_span = lo.to(self.prev_span);
if is_auto == IsAuto::Yes {
let msg = "trait aliases cannot be `auto`";
self.struct_span_err(self.prev_span, msg)
.span_label(self.prev_span, msg)
self.struct_span_err(whole_span, msg)
.span_label(whole_span, msg)
.emit();
}
if unsafety != Unsafety::Normal {
let msg = "trait aliases cannot be `unsafe`";
self.struct_span_err(self.prev_span, msg)
.span_label(self.prev_span, msg)
self.struct_span_err(whole_span, msg)
.span_label(whole_span, msg)
.emit();
}
Ok((ident, ItemKind::TraitAlias(tps, bounds), None))
} else {
// It's a normal trait.

3
src/test/ui/traits/trait-alias/trait-alias-syntax-fail.rs
View file

@ -4,4 +4,7 @@ trait Foo {}
auto trait A = Foo; //~ ERROR trait aliases cannot be `auto`
unsafe trait B = Foo; //~ ERROR trait aliases cannot be `unsafe`
trait C: Ord = Eq; //~ ERROR bounds are not allowed on trait aliases
trait D: = Eq; //~ ERROR bounds are not allowed on trait aliases
fn main() {}

22
src/test/ui/traits/trait-alias/trait-alias-syntax-fail.stderr
View file

@ -1,14 +1,26 @@
error: trait aliases cannot be `auto`
--> $DIR/trait-alias-syntax-fail.rs:4:19
--> $DIR/trait-alias-syntax-fail.rs:4:1
|
LL | auto trait A = Foo;
| ^ trait aliases cannot be `auto`
| ^^^^^^^^^^^^^^^^^^^ trait aliases cannot be `auto`
error: trait aliases cannot be `unsafe`
--> $DIR/trait-alias-syntax-fail.rs:5:21
--> $DIR/trait-alias-syntax-fail.rs:5:1
|
LL | unsafe trait B = Foo;
| ^ trait aliases cannot be `unsafe`
| ^^^^^^^^^^^^^^^^^^^^^ trait aliases cannot be `unsafe`
error: aborting due to 2 previous errors
error: bounds are not allowed on trait aliases
--> $DIR/trait-alias-syntax-fail.rs:7:8
|
LL | trait C: Ord = Eq;
| ^^^^^
error: bounds are not allowed on trait aliases
--> $DIR/trait-alias-syntax-fail.rs:8:8
|
LL | trait D: = Eq;
| ^
error: aborting due to 4 previous errors