Cloning the predicates and loop lists in the control directives inside the…

Cloning the predicates and loop lists in the control directives inside the function evaluator. Necessary in case they get modified during the in-place evaluation.

eval_apply.cpp

@@ -787,7 +787,8 @@ namespace Sass {
         case Node::if_directive: {
           for (size_t j = 0, S = stm.size(); j < S; j += 2) {
             if (stm[j].type() != Node::block) {
-              Node predicate_val(eval(stm[j], Node(), bindings, ctx.function_env, new_Node, ctx));
+              Node pred(new_Node(stm[j]));
+              Node predicate_val(eval(pred, Node(), bindings, ctx.function_env, new_Node, ctx));
               if ((predicate_val.type() != Node::boolean) || predicate_val.boolean_value()) {
                 Node v(function_eval(name, stm[j+1], bindings, new_Node, ctx));
                 if (v.is_null_ptr()) break;
@@ -806,8 +807,8 @@ namespace Sass {
         case Node::for_to_directive: {
           Node::Type for_type = stm.type();
           Node iter_var(stm[0]);
-          Node lower_bound(eval(stm[1], Node(), bindings, ctx.function_env, new_Node, ctx));
-          Node upper_bound(eval(stm[2], Node(), bindings, ctx.function_env, new_Node, ctx));
+          Node lower_bound(eval(new_Node(stm[1]), Node(), bindings, ctx.function_env, new_Node, ctx));
+          Node upper_bound(eval(new_Node(stm[2]), Node(), bindings, ctx.function_env, new_Node, ctx));
           Node for_body(stm[3]);
           Environment for_env; // re-use this env for each iteration
           for_env.link(bindings);
@@ -823,7 +824,7 @@ namespace Sass {
 
         case Node::each_directive: {
           Node iter_var(stm[0]);
-          Node list(eval(stm[1], Node(), bindings, ctx.function_env, new_Node, ctx));
+          Node list(eval(new_Node(stm[1]), Node(), bindings, ctx.function_env, new_Node, ctx));
           if (list.type() != Node::comma_list && list.type() != Node::space_list) {
             list = (new_Node(Node::space_list, list.path(), list.line(), 1) << list);
           }
@@ -843,7 +844,7 @@ namespace Sass {
         } break;
 
         case Node::while_directive: {
-          Node pred_expr(stm[0]);
+          Node pred_expr(new_Node(stm[0]));
           Node while_body(stm[1]);
           Environment while_env; // re-use this env for each iteration
           while_env.link(bindings);
@@ -851,7 +852,7 @@ namespace Sass {
           while ((pred_val.type() != Node::boolean) || pred_val.boolean_value()) {
             Node v(function_eval(name, while_body, while_env, new_Node, ctx));
             if (v.is_null_ptr()) {
-              pred_val = eval(pred_expr, Node(), bindings, ctx.function_env, new_Node, ctx);
+              pred_val = eval(new_Node(stm[0]), Node(), bindings, ctx.function_env, new_Node, ctx);
               continue;
             }
             else return v;