Try to fix weird memory leak

Author: mgreter

src/environment.cpp

@@ -179,12 +179,12 @@ namespace Sass {
       }
 
       if (!result) result = a->value()->accept(this);
-
+      if (result) result = withoutSlash(result);
 
       if (auto frame = compiler.getCurrentScope()) {
         a->vidx(frame->setModVar(
           a->variable(), a->ns(),
-          withoutSlash(result),
+          result,
           a->is_default(),
           a->pstate()));
       }

src/eval.cpp

@@ -645,14 +645,17 @@ namespace Sass {
 
     // Collect positional args by evaluating input arguments
     positional.reserve(arguments->positional().size() + 1);
-    for (const auto& arg : arguments->positional()) {
-      positional.emplace_back(withoutSlash(arg->accept(this)));
+    for (const auto& arg : arguments->positional())
+    {
+      ValueObj result(arg->accept(this));
+      positional.emplace_back(withoutSlash(result));
     }
 
     // Collect named args by evaluating input arguments
     for (const auto& kv : arguments->named()) {
+      ValueObj result(kv.second->accept(this));
       named.insert(std::make_pair(kv.first,
-        withoutSlash(kv.second->accept(this))));
+        withoutSlash(result)));
     }
 
     // Abort if we don't take any restargs
@@ -663,7 +666,8 @@ namespace Sass {
     }
 
     // Evaluate the variable expression (
-    ValueObj rest = withoutSlash(arguments->restArg()->accept(this));
+    ValueObj result = arguments->restArg()->accept(this);
+    ValueObj rest = withoutSlash(result);
 
     SassSeparator separator = SASS_UNDEF;