rustc: Make 'do' work with effects the same as 'for'

src/rustc/middle/borrowck/check_loans.rs

@@ -185,7 +185,7 @@ impl methods for check_loan_ctxt {
                 if is_fn_arg { ret; } // case (a) above
               }
               ast::expr_fn_block(*) | ast::expr_fn(*) |
-              ast::expr_loop_body(*) {
+              ast::expr_loop_body(*) | ast::expr_do_body(*) {
                 if self.is_stack_closure(expr.id) { ret; } // case (b) above
               }
               _ {}

src/test/run-pass/do-pure.rs

@@ -0,0 +1,10 @@
+pure fn f(f: fn()) {
+}
+
+pure fn g() {
+    // `f { || }` is considered pure, so `do f { || }` should be too
+    do f { || }
+}
+
+fn main() {
+}