Make it again possible to initialize resource locals via assignment

Some special cases allow both 'let a <- my_resource(x)' and
'let a = my_resource(x)' to work as expected despite ostensibly being
copies and moves.

Author: brson

src/comp/middle/kind.rs

@@ -183,6 +183,12 @@ fn need_shared_or_pinned_ctor(tcx: ty::ctxt, a: @ast::expr, descr: str) {
           ast::expr_rec(_, _) {
             true
           }
+          ast::expr_unary(ast::uniq(_), _) {
+            true
+          }
+          ast::expr_tup(_) {
+            true
+          }
           _ { false }
         }
     }
@@ -266,14 +272,12 @@ fn check_stmt(tcx: ty::ctxt, stmt: @ast::stmt) {
         for (let_style, local) in locals {
             alt local.node.init {
               option::some({op: ast::init_assign., expr}) {
-                need_expr_kind(tcx, expr,
-                               ast::kind_shared,
-                               "local initializer");
+                need_shared_or_pinned_ctor(tcx, expr,
+                                           "local initializer");
               }
               option::some({op: ast::init_move., expr}) {
-                // FIXME: Should be as above but moving may be the
-                // only way available currently to assign a resource
-                // to a local.
+                need_shared_or_pinned_ctor(tcx, expr,
+                                           "local initializer");
               }
               option::none. { /* fall through */ }
             }

src/test/compile-fail/resource-let.rs

@@ -0,0 +1,7 @@
+resource r(i: int) {
+}
+
+fn main() {
+    // Even though this looks like a copy, it's guaranteed not to be
+    let a = r(0);
+}

src/test/compile-fail/unique-pinned-nocopy-2.rs

@@ -0,0 +1,11 @@
+resource r(i: @mutable int) {
+    *i = *i + 1;
+}
+
+fn main() {
+    let i = @mutable 0;
+    {
+        let j = ~r(i);
+    }
+    assert *i == 1;
+}