From 56d765d0eb2121e4a345656351a24cb0d9d68b22 Mon Sep 17 00:00:00 2001
From: Ariel Ben-Yehuda <ariel.byd@gmail.com>
Date: Tue, 9 Jun 2015 21:33:28 +0300
Subject: [PATCH] Simplify and type_known_to_meet_builtin_bound and make it
more correct when associated types are involved.
---
src/librustc/middle/traits/mod.rs | 75 ++++++----------------------
src/test/compile-fail/issue-25700.rs | 24 +++++++++
src/test/run-pass/issue-25700-1.rs | 22 ++++++++
3 files changed, 62 insertions(+), 59 deletions(-)
create mode 100644 src/test/compile-fail/issue-25700.rs
create mode 100644 src/test/run-pass/issue-25700-1.rs
diff --git a/src/librustc/middle/traits/mod.rs b/src/librustc/middle/traits/mod.rs
index 50536f586e7..fb6bac9ea06 100644
--- a/src/librustc/middle/traits/mod.rs
+++ b/src/librustc/middle/traits/mod.rs
@@ -304,12 +304,12 @@ pub fn predicates_for_generics<'tcx>(tcx: &ty::ctxt<'tcx>,
/// `bound` or is not known to meet bound (note that this is
/// conservative towards *no impl*, which is the opposite of the
/// `evaluate` methods).
-pub fn evaluate_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
- typer: &ty::ClosureTyper<'tcx>,
- ty: Ty<'tcx>,
- bound: ty::BuiltinBound,
- span: Span)
- -> SelectionResult<'tcx, ()>
+pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
+ typer: &ty::ClosureTyper<'tcx>,
+ ty: Ty<'tcx>,
+ bound: ty::BuiltinBound,
+ span: Span)
+ -> bool
{
debug!("type_known_to_meet_builtin_bound(ty={}, bound={:?})",
ty.repr(infcx.tcx),
@@ -327,61 +327,18 @@ pub fn evaluate_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
// Note: we only assume something is `Copy` if we can
// *definitively* show that it implements `Copy`. Otherwise,
// assume it is move; linear is always ok.
- let result = match fulfill_cx.select_all_or_error(infcx, typer) {
- Ok(()) => Ok(Some(())), // Success, we know it implements Copy.
- Err(errors) => {
- // If there were any hard errors, propagate an arbitrary
- // one of those. If no hard errors at all, report
- // ambiguity.
- let sel_error =
- errors.iter()
- .filter_map(|err| {
- match err.code {
- CodeAmbiguity => None,
- CodeSelectionError(ref e) => Some(e.clone()),
- CodeProjectionError(_) => {
- infcx.tcx.sess.span_bug(
- span,
- "projection error while selecting?")
- }
- }
- })
- .next();
- match sel_error {
- None => { Ok(None) }
- Some(e) => { Err(e) }
- }
- }
- };
-
- debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} result={:?}",
- ty.repr(infcx.tcx),
- bound,
- result);
-
- result
-}
-
-pub fn type_known_to_meet_builtin_bound<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
- typer: &ty::ClosureTyper<'tcx>,
- ty: Ty<'tcx>,
- bound: ty::BuiltinBound,
- span: Span)
- -> bool
-{
- match evaluate_builtin_bound(infcx, typer, ty, bound, span) {
- Ok(Some(())) => {
- // definitely impl'd
+ match fulfill_cx.select_all_or_error(infcx, typer) {
+ Ok(()) => {
+ debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} success",
+ ty.repr(infcx.tcx),
+ bound);
true
}
- Ok(None) => {
- // ambiguous: if coherence check was successful, shouldn't
- // happen, but we might have reported an error and been
- // soldering on, so just treat this like not implemented
- false
- }
- Err(_) => {
- // errors: not implemented.
+ Err(e) => {
+ debug!("type_known_to_meet_builtin_bound: ty={} bound={:?} errors={}",
+ ty.repr(infcx.tcx),
+ bound,
+ e.repr(infcx.tcx));
false
}
}
diff --git a/src/test/compile-fail/issue-25700.rs b/src/test/compile-fail/issue-25700.rs
new file mode 100644
index 00000000000..477c3237f84
--- /dev/null
+++ b/src/test/compile-fail/issue-25700.rs
@@ -0,0 +1,24 @@
+// 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.
+
+struct S<T: 'static>(Option<&'static T>);
+
+trait Tr { type Out; }
+impl<T> Tr for T { type Out = T; }
+
+impl<T: 'static> Copy for S<T> where S<T>: Tr<Out=T> {}
+impl<T: 'static> Clone for S<T> where S<T>: Tr<Out=T> {
+ fn clone(&self) -> Self { *self }
+}
+fn main() {
+ let t = S::<()>(None);
+ drop(t);
+ drop(t); //~ ERROR use of moved value
+}
diff --git a/src/test/run-pass/issue-25700-1.rs b/src/test/run-pass/issue-25700-1.rs
new file mode 100644
index 00000000000..57f5b84b285
--- /dev/null
+++ b/src/test/run-pass/issue-25700-1.rs
@@ -0,0 +1,22 @@
+// 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.
+
+struct S<T: 'static>(Option<&'static T>);
+
+trait Tr { type Out; }
+impl<T> Tr for T { type Out = T; }
+
+impl<T: 'static> Copy for S<T> where S<T>: Tr<Out=T> {}
+impl<T: 'static> Clone for S<T> where S<T>: Tr<Out=T> {
+ fn clone(&self) -> Self { *self }
+}
+fn main() {
+ S::<()>(None);
+}