OIBIT: for PhantomData<T> check T rather than the struct itself

This commit is contained in:
Jorge Aparicio 2015-03-05 16:20:02 -05:00
parent 68740b4054
commit f0897aa17f
2 changed files with 48 additions and 0 deletions

View File

@ -1700,6 +1700,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
// for `PhantomData<T>`, we pass `T`
ty::ty_struct(def_id, substs)
if Some(def_id) == self.tcx().lang_items.phantom_data() =>
{
Some(substs.types.get_slice(TypeSpace).to_vec())
}
ty::ty_struct(def_id, substs) => {
Some(ty::struct_fields(self.tcx(), def_id, substs).iter()
.map(|f| f.mt.ty)

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@ -0,0 +1,41 @@
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Ensure that OIBIT checks `T` when it encounters a `PhantomData<T>` field, instead of checking
// the `PhantomData<T>` type itself (which almost always implements a "default" trait
// (`impl Trait for ..`))
#![feature(optin_builtin_traits)]
use std::marker::{MarkerTrait, PhantomData};
unsafe trait Zen: MarkerTrait {}
unsafe impl Zen for .. {}
unsafe impl<'a, T: 'a> Zen for &'a T where T: Sync {}
struct Guard<'a, T: 'a> {
_marker: PhantomData<&'a T>,
}
struct Nested<T>(T);
fn is_zen<T: Zen>(_: T) {}
fn not_sync<T>(x: Guard<T>) {
is_zen(x) //~ error: the trait `core::marker::Sync` is not implemented for the type `T`
}
fn nested_not_sync<T>(x: Nested<Guard<T>>) {
is_zen(x) //~ error: the trait `core::marker::Sync` is not implemented for the type `T`
}
fn main() {}