From afb20775d1836c79975dfb9889fdeffe0c8baf58 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Tue, 13 Aug 2013 14:59:33 -0400
Subject: [PATCH 1/2] Fix freezing of @mut Objects when passing as argument
---
src/librustc/middle/typeck/infer/coercion.rs | 15 +++----
.../run-fail/borrowck-wg-fail-object-arg.rs | 22 ++++++++++
...objects-coerce-from-managed-to-borrowed.rs | 44 +++++++++++++++++++
3 files changed, 73 insertions(+), 8 deletions(-)
create mode 100644 src/test/run-fail/borrowck-wg-fail-object-arg.rs
create mode 100644 src/test/run-pass/objects-coerce-from-managed-to-borrowed.rs
diff --git a/src/librustc/middle/typeck/infer/coercion.rs b/src/librustc/middle/typeck/infer/coercion.rs
index f2bde146ea7..88f7ffbfd23 100644
--- a/src/librustc/middle/typeck/infer/coercion.rs
+++ b/src/librustc/middle/typeck/infer/coercion.rs
@@ -121,9 +121,9 @@ impl Coerce {
};
}
- ty::ty_trait(_, _, ty::RegionTraitStore(*), _, _) => {
+ ty::ty_trait(_, _, ty::RegionTraitStore(*), m, _) => {
return do self.unpack_actual_value(a) |sty_a| {
- self.coerce_borrowed_object(a, sty_a, b)
+ self.coerce_borrowed_object(a, sty_a, b, m)
};
}
@@ -274,7 +274,8 @@ impl Coerce {
fn coerce_borrowed_object(&self,
a: ty::t,
sty_a: &ty::sty,
- b: ty::t) -> CoerceResult
+ b: ty::t,
+ b_mutbl: ast::mutability) -> CoerceResult
{
debug!("coerce_borrowed_object(a=%s, sty_a=%?, b=%s)",
a.inf_str(self.infcx), sty_a,
@@ -282,16 +283,14 @@ impl Coerce {
let tcx = self.infcx.tcx;
let r_a = self.infcx.next_region_var(Coercion(self.trace));
- let trt_mut;
let a_borrowed = match *sty_a {
ty::ty_trait(_, _, ty::RegionTraitStore(_), _, _) => {
return self.subtype(a, b);
}
- ty::ty_trait(did, ref substs, _, m, b) => {
- trt_mut = m;
+ ty::ty_trait(did, ref substs, _, _, b) => {
ty::mk_trait(tcx, did, substs.clone(),
- ty::RegionTraitStore(r_a), m, b)
+ ty::RegionTraitStore(r_a), b_mutbl, b)
}
_ => {
return self.subtype(a, b);
@@ -301,7 +300,7 @@ impl Coerce {
if_ok!(self.tys(a_borrowed, b));
Ok(Some(@AutoDerefRef(AutoDerefRef {
autoderefs: 0,
- autoref: Some(AutoBorrowObj(r_a, trt_mut))
+ autoref: Some(AutoBorrowObj(r_a, b_mutbl))
})))
}
diff --git a/src/test/run-fail/borrowck-wg-fail-object-arg.rs b/src/test/run-fail/borrowck-wg-fail-object-arg.rs
new file mode 100644
index 00000000000..c70d752ef30
--- /dev/null
+++ b/src/test/run-fail/borrowck-wg-fail-object-arg.rs
@@ -0,0 +1,22 @@
+// error-pattern:borrowed
+
+trait Foo {
+ fn foo(&self, @mut int);
+}
+
+impl Foo for int {
+ fn foo(&self, x: @mut int) {
+ *x += *self;
+ }
+}
+
+fn it_takes_two(f: &Foo, g: &mut Foo) {
+}
+
+fn main() {
+ let x = @mut 3_i;
+ let y = x as @mut Foo;
+ let z = y;
+
+ it_takes_two(y, z);
+}
diff --git a/src/test/run-pass/objects-coerce-from-managed-to-borrowed.rs b/src/test/run-pass/objects-coerce-from-managed-to-borrowed.rs
new file mode 100644
index 00000000000..fe4eb2ea48e
--- /dev/null
+++ b/src/test/run-pass/objects-coerce-from-managed-to-borrowed.rs
@@ -0,0 +1,44 @@
+// Copyright 2012 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.
+
+// Test that we can coerce an `@Object` to an `&Object`
+
+trait Foo {
+ fn foo(&self) -> uint;
+ fn bar(&mut self) -> uint;
+}
+
+impl Foo for uint {
+ fn foo(&self) -> uint {
+ *self
+ }
+
+ fn bar(&mut self) -> uint {
+ *self += 1;
+ *self
+ }
+}
+
+fn do_it_mut(obj: &mut Foo) {
+ let x = obj.bar();
+ let y = obj.foo();
+ assert_eq!(x, y);
+}
+
+fn do_it_imm(obj: &Foo, v: uint) {
+ let y = obj.foo();
+ assert_eq!(v, y);
+}
+
+fn main() {
+ let x = @mut 22u as @mut Foo;
+ do_it_mut(x);
+ do_it_imm(x, 23u);
+}
From bf2d3c840bc9584055778ed6b08ddf6e32a0f45a Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Tue, 13 Aug 2013 15:46:08 -0400
Subject: [PATCH 2/2] Reborrow even when passing &Object to &Object, so as to
permit freezing
---
src/librustc/middle/typeck/check/regionck.rs | 5 +-
src/librustc/middle/typeck/infer/coercion.rs | 5 +-
.../objects-coerce-freeze-borrored.rs | 48 +++++++++++++++++++
3 files changed, 53 insertions(+), 5 deletions(-)
create mode 100644 src/test/run-pass/objects-coerce-freeze-borrored.rs
diff --git a/src/librustc/middle/typeck/check/regionck.rs b/src/librustc/middle/typeck/check/regionck.rs
index d034277d44a..21cabb5a745 100644
--- a/src/librustc/middle/typeck/check/regionck.rs
+++ b/src/librustc/middle/typeck/check/regionck.rs
@@ -391,7 +391,7 @@ fn visit_expr(expr: @ast::expr, (rcx, v): (@mut Rcx, rvt)) {
let target_ty = rcx.resolve_node_type(expr.id);
match ty::get(target_ty).sty {
ty::ty_trait(_, _, ty::RegionTraitStore(trait_region), _, _) => {
- let source_ty = rcx.fcx.expr_ty(source);
+ let source_ty = rcx.resolve_expr_type_adjusted(source);
constrain_regions_in_type(
rcx,
trait_region,
@@ -1153,17 +1153,20 @@ pub mod guarantor {
match ty::get(ty).sty {
ty::ty_rptr(r, _) |
ty::ty_evec(_, ty::vstore_slice(r)) |
+ ty::ty_trait(_, _, ty::RegionTraitStore(r), _, _) |
ty::ty_estr(ty::vstore_slice(r)) => {
BorrowedPointer(r)
}
ty::ty_uniq(*) |
ty::ty_estr(ty::vstore_uniq) |
+ ty::ty_trait(_, _, ty::UniqTraitStore, _, _) |
ty::ty_evec(_, ty::vstore_uniq) => {
OwnedPointer
}
ty::ty_box(*) |
ty::ty_ptr(*) |
ty::ty_evec(_, ty::vstore_box) |
+ ty::ty_trait(_, _, ty::BoxTraitStore, _, _) |
ty::ty_estr(ty::vstore_box) => {
OtherPointer
}
diff --git a/src/librustc/middle/typeck/infer/coercion.rs b/src/librustc/middle/typeck/infer/coercion.rs
index 88f7ffbfd23..7736dbbb99d 100644
--- a/src/librustc/middle/typeck/infer/coercion.rs
+++ b/src/librustc/middle/typeck/infer/coercion.rs
@@ -285,9 +285,6 @@ impl Coerce {
let r_a = self.infcx.next_region_var(Coercion(self.trace));
let a_borrowed = match *sty_a {
- ty::ty_trait(_, _, ty::RegionTraitStore(_), _, _) => {
- return self.subtype(a, b);
- }
ty::ty_trait(did, ref substs, _, _, b) => {
ty::mk_trait(tcx, did, substs.clone(),
ty::RegionTraitStore(r_a), b_mutbl, b)
@@ -297,7 +294,7 @@ impl Coerce {
}
};
- if_ok!(self.tys(a_borrowed, b));
+ if_ok!(self.subtype(a_borrowed, b));
Ok(Some(@AutoDerefRef(AutoDerefRef {
autoderefs: 0,
autoref: Some(AutoBorrowObj(r_a, b_mutbl))
diff --git a/src/test/run-pass/objects-coerce-freeze-borrored.rs b/src/test/run-pass/objects-coerce-freeze-borrored.rs
new file mode 100644
index 00000000000..4dda5ca556e
--- /dev/null
+++ b/src/test/run-pass/objects-coerce-freeze-borrored.rs
@@ -0,0 +1,48 @@
+// Copyright 2012 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.
+
+// Test that we can coerce an `@Object` to an `&Object`
+
+trait Foo {
+ fn foo(&self) -> uint;
+ fn bar(&mut self) -> uint;
+}
+
+impl Foo for uint {
+ fn foo(&self) -> uint {
+ *self
+ }
+
+ fn bar(&mut self) -> uint {
+ *self += 1;
+ *self
+ }
+}
+
+fn do_it_mut(obj: &mut Foo) {
+ let x = obj.bar();
+ let y = obj.foo();
+ assert_eq!(x, y);
+
+ do_it_imm(obj, y);
+}
+
+fn do_it_imm(obj: &Foo, v: uint) {
+ let y = obj.foo();
+ assert_eq!(v, y);
+}
+
+fn main() {
+ let mut x = 22_u;
+ let obj = &mut x as &mut Foo;
+ do_it_mut(obj);
+ do_it_imm(obj, 23u);
+ do_it_mut(obj);
+}