Advice to use Box<T> not ~T

src/librustc/middle/typeck/astconv.rs

@@ -653,7 +653,7 @@ pub fn ast_ty_to_ty<AC:AstConv, RS:RegionScope>(
                         tcx.sess.span_err(
                             ast_ty.span,
                             format!("reference to trait `{name}` where a type is expected; \
-                                    try `~{name}` or `&{name}`", name=path_str));
+                                    try `Box<{name}>` or `&{name}`", name=path_str));
                         ty::mk_err()
                     }
                     ast::DefTy(did) | ast::DefStruct(did) => {

src/test/compile-fail/issue-5883.rs

@@ -11,15 +11,15 @@
 trait A {}
 
 struct Struct {
-    r: A //~ ERROR reference to trait `A` where a type is expected; try `~A` or `&A`
+    r: A //~ ERROR reference to trait `A` where a type is expected; try `Box<A>` or `&A`
 }
 
 fn new_struct(r: A) -> Struct {
-    //~^ ERROR reference to trait `A` where a type is expected; try `~A` or `&A`
+    //~^ ERROR reference to trait `A` where a type is expected; try `Box<A>` or `&A`
     Struct { r: r }
 }
 
 trait Curve {}
 enum E {X(Curve)}
-//~^ ERROR reference to trait `Curve` where a type is expected; try `~Curve` or `&Curve`
+//~^ ERROR reference to trait `Curve` where a type is expected; try `Box<Curve>` or `&Curve`
 fn main() {}

src/test/compile-fail/trait-bounds-not-on-bare-trait.rs

@@ -14,7 +14,7 @@ trait Foo {
 // This should emit the less confusing error, not the more confusing one.
 
 fn foo(_x: Foo:Send) {
-    //~^ERROR reference to trait `Foo` where a type is expected; try `~Foo` or `&Foo`
+    //~^ERROR reference to trait `Foo` where a type is expected; try `Box<Foo>` or `&Foo`
 }
 
 fn main() { }