diff options
7 files changed, 59 insertions, 0 deletions
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs index 2ae77046a90..3da9383762b 100644 --- a/src/librustc/ty/mod.rs +++ b/src/librustc/ty/mod.rs @@ -2230,6 +2230,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { /// Returns true if the impls are the same polarity and are implementing /// a trait which contains no items pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool { + if !self.sess.features.borrow().overlapping_marker_traits { + return false; + } let trait1_is_empty = self.impl_trait_ref(def_id1) .map_or(false, |trait_ref| { self.associated_item_def_ids(trait_ref.def_id).is_empty() diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index 8b62416dcbd..6e455234196 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -349,6 +349,9 @@ declare_features! ( // Allows module-level inline assembly by way of global_asm!() (active, global_asm, "1.18.0", Some(35119)), + + // Allows overlapping impls of marker traits + (active, overlapping_marker_traits, "1.18.0", Some(29864)), ); declare_features! ( diff --git a/src/test/compile-fail/coherence-conflicting-negative-trait-impl.rs b/src/test/compile-fail/coherence-conflicting-negative-trait-impl.rs index d841e8c41d9..8e9d1eff345 100644 --- a/src/test/compile-fail/coherence-conflicting-negative-trait-impl.rs +++ b/src/test/compile-fail/coherence-conflicting-negative-trait-impl.rs @@ -9,6 +9,7 @@ // except according to those terms. #![feature(optin_builtin_traits)] +#![feature(overlapping_marker_traits)] trait MyTrait {} diff --git a/src/test/compile-fail/coherence-impls-send.rs b/src/test/compile-fail/coherence-impls-send.rs index d0e6bc6a1c6..9caaee41aeb 100644 --- a/src/test/compile-fail/coherence-impls-send.rs +++ b/src/test/compile-fail/coherence-impls-send.rs @@ -9,6 +9,7 @@ // except according to those terms. #![feature(optin_builtin_traits)] +#![feature(overlapping_marker_traits)] use std::marker::Copy; diff --git a/src/test/compile-fail/overlapping-impls-requires-feature-gate.rs b/src/test/compile-fail/overlapping-impls-requires-feature-gate.rs new file mode 100644 index 00000000000..bf2b06dd8ba --- /dev/null +++ b/src/test/compile-fail/overlapping-impls-requires-feature-gate.rs @@ -0,0 +1,17 @@ +// Copyright 2017 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. + +trait MyMarker {} + +impl<T> MyMarker for T {} +impl<T> MyMarker for Vec<T> {} +//~^ ERROR E0119 + +fn main() {} diff --git a/src/test/run-pass/overlap-doesnt-conflict-with-specialization.rs b/src/test/run-pass/overlap-doesnt-conflict-with-specialization.rs new file mode 100644 index 00000000000..ed45d81c0d6 --- /dev/null +++ b/src/test/run-pass/overlap-doesnt-conflict-with-specialization.rs @@ -0,0 +1,27 @@ +// Copyright 2017 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. + +#![feature(overlapping_marker_traits)] +#![feature(specialization)] + +trait MyMarker {} + +impl<T> MyMarker for T {} +impl<T> MyMarker for Vec<T> {} + +fn foo<T: MyMarker>(t: T) -> T { + t +} + +fn main() { + assert_eq!(1, foo(1)); + assert_eq!(2.0, foo(2.0)); + assert_eq!(vec![1], foo(vec![1])); +} diff --git a/src/test/run-pass/overlap-permitted-for-marker-traits.rs b/src/test/run-pass/overlap-permitted-for-marker-traits.rs index b0b1930d274..45085c093fc 100644 --- a/src/test/run-pass/overlap-permitted-for-marker-traits.rs +++ b/src/test/run-pass/overlap-permitted-for-marker-traits.rs @@ -8,11 +8,18 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. +#![feature(overlapping_marker_traits)] +#![feature(optin_builtin_traits)] + trait MyMarker {} impl<T: Copy> MyMarker for T {} impl<T: Eq> MyMarker for T {} +struct MyStruct; +impl !Send for MyStruct {} +impl !Send for MyStruct {} + fn foo<T: MyMarker>(t: T) -> T { t } |