diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs index 8cafa77973909..ffa1530a14e26 100644 --- a/src/librustc/traits/object_safety.rs +++ b/src/librustc/traits/object_safety.rs @@ -228,9 +228,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { /// otherwise ensure that they cannot be used when `Self=Trait`. pub fn is_vtable_safe_method(self, trait_def_id: DefId, - method: &ty::Method<'tcx>) + method: &ty::Method<'gcx>) -> bool { + // Any method that has a `Self : Sized` requisite can't be called. + if self.generics_require_sized_self(&method.generics, &method.predicates) { + return false; + } + self.virtual_call_violation_for_method(trait_def_id, method).is_none() } diff --git a/src/test/run-pass/trait-object-exclusion.rs b/src/test/run-pass/trait-object-exclusion.rs new file mode 100644 index 0000000000000..13b725b7c9eff --- /dev/null +++ b/src/test/run-pass/trait-object-exclusion.rs @@ -0,0 +1,28 @@ +// Copyright 2016 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +trait Future: 'static { + // The requirement for Self: Sized must prevent instantiation of + // Future::forget in vtables, otherwise there's an infinite type + // recursion through as Future>::forget. + fn forget(self) where Self: Sized { + Box::new(Map(self)) as Box; + } +} + +struct Map(A); +impl Future for Map {} + +pub struct Promise; +impl Future for Promise {} + +fn main() { + Promise.forget(); +}