Try to fix memory leak

Author: mgreter

src/ast_values.cpp

@@ -1114,12 +1114,14 @@ namespace Sass {
   // Implement delayed value fetcher
   /////////////////////////////////////////////////////////////////////////
 
+  // The original value may not be returned
+  // Therefore make sure original is collected
   Value* Number::withoutSlash()
   {
     if (!hasAsSlash()) return this;
     // we are the only holder of this item
     // therefore should be safe to alter it
-    if (this->refcount == 1) {
+    if (this->refcount <= 1) {
       lhsAsSlash_.clear();
       rhsAsSlash_.clear();
       return this;

src/eval.cpp

@@ -83,15 +83,18 @@ namespace Sass {
   /////////////////////////////////////////////////////////////////////////
   /////////////////////////////////////////////////////////////////////////
 
-  Value* Eval::withoutSlash(Value* value) {
+  Value* Eval::withoutSlash(ValueObj value) {
+    if (value == nullptr) return value;
     Number* number = value->isaNumber();
     if (number && number->hasAsSlash()) {
       logger.addDeprecation("Using / for division is deprecated and will be removed " 
         "in LibSass 4.1.0.\n\nRecommendation: math.div(" + number->lhsAsSlash()->inspect() +
         ", " + number->rhsAsSlash()->inspect() + ")\n\nMore info and automated migrator: "
         "https://sass-lang.com/d/slash-div", value->pstate());
     }
-    return value->withoutSlash();
+    // Make sure to collect all memory
+    ValueObj result = value->withoutSlash();
+    return result.detach();
   }
 
   /////////////////////////////////////////////////////////////////////////
@@ -284,7 +287,7 @@ namespace Sass {
 
     }
 
-    for (auto& arg : positional) {
+    for (ValueObj& arg : positional) {
       arg = withoutSlash(arg);
     }
 

src/eval.hpp

@@ -28,7 +28,7 @@ namespace Sass {
     void exposeFwdRule(ForwardRule* rule);
     void exposeImpRule(IncludeImport* rule);
 
-    Value* withoutSlash(Value* value);
+    Value* withoutSlash(ValueObj value);
 
     // Some references
     Logger& logger;