rustc: Remove the artificial block in ty.rs. Fixes self-hosting. Add a test case for this, XFAIL'd.

src/comp/middle/ty.rs

@@ -1905,7 +1905,7 @@ fn expr_ann(&@ast.expr e) -> ast.ann {
 // instead of "fn(&T) -> T with T = int". If this isn't what you want, see
 // expr_ty_params_and_ty() below.
 fn expr_ty(ctxt cx, @ast.expr expr) -> t {
-    { ret ann_to_monotype(cx, expr_ann(expr)); }
+    ret ann_to_monotype(cx, expr_ann(expr));
 }
 
 fn expr_ty_params_and_ty(ctxt cx, @ast.expr expr) -> tup(vec[t], t) {

src/test/run-pass/artificial-block.rs

@@ -0,0 +1,12 @@
+// xfail-stage0
+// xfail-stage1
+// xfail-stage2
+fn f() -> int {
+    { ret 3; }
+}
+
+fn main() {
+    assert(f() == 3);
+}
+
+