Fix MSVC issue (invalid selector schema use as statement)

src/ast.hpp

@@ -396,7 +396,7 @@ namespace Sass {
     ADD_PROPERTY(bool, group_end)
   public:
     Statement(ParserState pstate, Statement_Type st = NONE, size_t t = 0)
-    : AST_Node(pstate), statement_type_(st), tabs_(t), group_end_(false)
+    : AST_Node(pstate), block_(0), statement_type_(st), tabs_(t), group_end_(false)
      { }
     virtual ~Statement() = 0;
     // needed for rearranging nested rulesets during CSS emission

src/cssize.cpp

@@ -102,10 +102,18 @@ namespace Sass {
   {
     p_stack.push_back(r);
     s_stack.push_back(dynamic_cast<Selector_List*>(r->selector()));
+    // this can return a string schema
+    // string schema is not a statement!
+    Statement* stmt = r->block()->perform(this);
+    // this should protect us (at least a bit) from our mess
+    // fixing this properly is harder that it should be ...
+    if (dynamic_cast<Statement*>((AST_Node*)stmt) == NULL) {
+      error("Illegal nesting: Only properties may be nested beneath properties.", r->block()->pstate());
+    }
     Ruleset* rr = SASS_MEMORY_NEW(ctx.mem, Ruleset,
                                   r->pstate(),
                                   r->selector(),
-                                  r->block()->perform(this)->block());
+                                  stmt->block());
     rr->is_root(r->is_root());
     // rr->tabs(r->block()->tabs());
     s_stack.pop_back();

src/expand.cpp

@@ -157,16 +157,17 @@ namespace Sass {
   {
     property_stack.push_back(p->property_fragment());
     Block* expanded_block = p->block()->perform(this)->block();
-
     for (size_t i = 0, L = expanded_block->length(); i < L; ++i) {
       Statement* stm = (*expanded_block)[i];
       if (Declaration* dec = static_cast<Declaration*>(stm)) {
         String_Schema* combined_prop = SASS_MEMORY_NEW(ctx.mem, String_Schema, p->pstate());
         if (!property_stack.empty()) {
-          *combined_prop << property_stack.back()->perform(&eval)
-                         << SASS_MEMORY_NEW(ctx.mem, String_Quoted,
-             p->pstate(), "-")
-             << dec->property(); // TODO: eval the prop into a string constant
+          *combined_prop << property_stack.back()->perform(&eval);
+          *combined_prop << SASS_MEMORY_NEW(ctx.mem, String_Quoted, p->pstate(), "-");
+          if (dec->property()) {
+            // we cannot directly add block (from dec->property()) to string schema (combined_prop)
+            *combined_prop << SASS_MEMORY_NEW(ctx.mem, String_Quoted, dec->pstate(), dec->property()->to_string());
+          }
         }
         else {
           *combined_prop << dec->property();