diff --git a/src/Makefile b/src/Makefile
index af3201211b1..3d5f5e868eb 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -498,8 +498,14 @@ TEST_XFAILS_LLVM := $(TASK_XFAILS) \
 
 TEST_XFAILS_SELF := $(filter-out \
                       $(addprefix test/run-pass/, \
+                        bool-not.rs \
+                        char.rs \
+                        div-mod.rs \
                         hello.rs \
-                        int.rs), \
+                        int.rs \
+                        item-name-overload.rs \
+                        multiline-comment.rs \
+                        ), \
                       $(wildcard test/*/*.rs test/*/*.rc))
 
 
diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index 2135a97dac9..0d042d0db03 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -67,6 +67,7 @@ tag stmt_ {
     stmt_decl(@decl);
     stmt_ret(option[@expr]);
     stmt_log(@expr);
+    stmt_check_expr(@expr);
     stmt_expr(@expr);
 }
 
diff --git a/src/comp/front/parser.rs b/src/comp/front/parser.rs
index 96158f1bd27..42ffc4c6538 100644
--- a/src/comp/front/parser.rs
+++ b/src/comp/front/parser.rs
@@ -690,6 +690,22 @@ io fn parse_stmt(parser p) -> @ast.stmt {
             ret @spanned(lo, hi, ast.stmt_log(e));
         }
 
+        case (token.CHECK) {
+            p.bump();
+            alt (p.peek()) {
+                case (token.LPAREN) {
+                    auto e = parse_expr(p);
+                    auto hi = p.get_span();
+                    expect(p, token.SEMI);
+                    ret @spanned(lo, hi, ast.stmt_check_expr(e));
+                }
+                case (_) {
+                    p.get_session().unimpl("constraint-check stmt");
+                }
+            }
+        }
+
+
         case (token.LET) {
             auto decl = parse_let(p);
             auto hi = p.get_span();
diff --git a/src/comp/middle/fold.rs b/src/comp/middle/fold.rs
index 4dd10871a8c..eeea6bba3f4 100644
--- a/src/comp/middle/fold.rs
+++ b/src/comp/middle/fold.rs
@@ -119,6 +119,9 @@ type ast_fold[ENV] =
      (fn(&ENV e, &span sp,
          @expr e) -> @stmt)                       fold_stmt_log,
 
+     (fn(&ENV e, &span sp,
+         @expr e) -> @stmt)                       fold_stmt_check_expr,
+
      (fn(&ENV e, &span sp,
          @expr e) -> @stmt)                       fold_stmt_expr,
 
@@ -393,6 +396,11 @@ fn fold_stmt[ENV](&ENV env, ast_fold[ENV] fld, &@stmt s) -> @stmt {
             ret fld.fold_stmt_log(env_, s.span, ee);
         }
 
+        case (ast.stmt_check_expr(?e)) {
+            auto ee = fold_expr(env_, fld, e);
+            ret fld.fold_stmt_check_expr(env_, s.span, ee);
+        }
+
         case (ast.stmt_expr(?e)) {
             auto ee = fold_expr(env_, fld, e);
             ret fld.fold_stmt_expr(env_, s.span, ee);
@@ -645,6 +653,10 @@ fn identity_fold_stmt_log[ENV](&ENV e, &span sp, @expr x) -> @stmt {
     ret @respan(sp, ast.stmt_log(x));
 }
 
+fn identity_fold_stmt_check_expr[ENV](&ENV e, &span sp, @expr x) -> @stmt {
+    ret @respan(sp, ast.stmt_check_expr(x));
+}
+
 fn identity_fold_stmt_expr[ENV](&ENV e, &span sp, @expr x) -> @stmt {
     ret @respan(sp, ast.stmt_expr(x));
 }
@@ -765,6 +777,8 @@ fn new_identity_fold[ENV]() -> ast_fold[ENV] {
          fold_stmt_decl   = bind identity_fold_stmt_decl[ENV](_,_,_),
          fold_stmt_ret    = bind identity_fold_stmt_ret[ENV](_,_,_),
          fold_stmt_log    = bind identity_fold_stmt_log[ENV](_,_,_),
+         fold_stmt_check_expr
+                          = bind identity_fold_stmt_check_expr[ENV](_,_,_),
          fold_stmt_expr   = bind identity_fold_stmt_expr[ENV](_,_,_),
 
          fold_item_fn   = bind identity_fold_item_fn[ENV](_,_,_,_,_),
diff --git a/src/comp/middle/resolve.rs b/src/comp/middle/resolve.rs
index 7951ec85a03..31aca9cc1bd 100644
--- a/src/comp/middle/resolve.rs
+++ b/src/comp/middle/resolve.rs
@@ -23,7 +23,7 @@ type env = rec(list[scope] scopes,
 
 fn lookup_name(&env e, ast.ident i) -> option[def] {
 
-    log "resolving name " + i;
+    // log "resolving name " + i;
 
     fn found_def_item(@ast.item i) -> option[def] {
         alt (i.node) {
@@ -108,7 +108,7 @@ fn fold_expr_name(&env e, &span sp, &ast.name n,
 
     alt (d_) {
         case (some[def](_)) {
-            log "resolved name " + n.node.ident;
+            // log "resolved name " + n.node.ident;
         }
         case (none[def]) {
             e.sess.err("unresolved name: " + n.node.ident);
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index a157d42df0b..cc1af53fbaf 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -791,6 +791,26 @@ fn trans_log(@block_ctxt cx, &ast.expr e) -> result {
     }
 }
 
+fn trans_check_expr(@block_ctxt cx, &ast.expr e) -> result {
+    auto cond_res = trans_expr(cx, e);
+
+    // FIXME: need pretty-printer.
+    auto V_expr_str = p2i(C_str(cx.fcx.tcx, "<expr>"));
+    auto V_filename = p2i(C_str(cx.fcx.tcx, e.span.filename));
+    auto V_line = e.span.lo.line as int;
+    auto args = vec(V_expr_str, V_filename, C_int(V_line));
+
+    auto fail_cx = new_empty_block_ctxt(cx.fcx);
+    auto fail_res = trans_upcall(fail_cx, "upcall_fail", args);
+
+    auto next_cx = new_extension_block_ctxt(cx);
+    fail_res.bcx.build.Br(next_cx.llbb);
+    cond_res.bcx.build.CondBr(cond_res.val,
+                              next_cx.llbb,
+                              fail_cx.llbb);
+    ret res(next_cx, C_nil());
+}
+
 fn trans_stmt(@block_ctxt cx, &ast.stmt s) -> result {
     auto sub = res(cx, C_nil());
     alt (s.node) {
@@ -798,6 +818,10 @@ fn trans_stmt(@block_ctxt cx, &ast.stmt s) -> result {
             sub.bcx = trans_log(cx, *a).bcx;
         }
 
+        case (ast.stmt_check_expr(?a)) {
+            sub.bcx = trans_check_expr(cx, *a).bcx;
+        }
+
         case (ast.stmt_expr(?e)) {
             sub.bcx = trans_expr(cx, *e).bcx;
         }