Merge pull request #3027 from mgreter/bugfix/misc-segfaults

Fix a few segfaults

src/ast_sel_weave.cpp

@@ -576,8 +576,12 @@ namespace Sass {
       // Prepare data structures
       choices.push_back(expanded);
       choices.push_back({ group });
-      groups1.erase(groups1.begin());
-      groups2.erase(groups2.begin());
+      if (!groups1.empty()) {
+        groups1.erase(groups1.begin());
+      }
+      if (!groups2.empty()) {
+        groups2.erase(groups2.begin());
+      }
 
     }
 

src/eval.cpp

@@ -690,9 +690,9 @@ namespace Sass {
                                                     b->op(), s_l->last(), b->right());
         bin_ex->is_delayed(b->left()->is_delayed() || b->right()->is_delayed()); // unverified
         for (size_t i = 0; i < s_l->length() - 1; ++i) {
-          ret_schema->append(Cast<PreValue>(s_l->at(i)->perform(this)));
+          ret_schema->append(s_l->at(i)->perform(this));
         }
-        ret_schema->append(Cast<PreValue>(bin_ex->perform(this)));
+        ret_schema->append(bin_ex->perform(this));
         return ret_schema->perform(this);
       }
     }
@@ -703,9 +703,9 @@ namespace Sass {
         Binary_Expression_Obj bin_ex = SASS_MEMORY_NEW(Binary_Expression, b->pstate(),
                                                     b->op(), b->left(), s_r->first());
         bin_ex->is_delayed(b->left()->is_delayed() || b->right()->is_delayed()); // verified
-        ret_schema->append(Cast<PreValue>(bin_ex->perform(this)));
+        ret_schema->append(bin_ex->perform(this));
         for (size_t i = 1; i < s_r->length(); ++i) {
-          ret_schema->append(Cast<PreValue>(s_r->at(i)->perform(this)));
+          ret_schema->append(s_r->at(i)->perform(this));
         }
         return ret_schema->perform(this);
       }

src/parser_selectors.cpp

@@ -140,10 +140,12 @@ namespace Sass {
         // parent selector only allowed at start
         // upcoming Sass may allow also trailing
         ParserState state(pstate);
-        SimpleSelectorObj prev = (*seq)[seq->length()-1];
-        std::string sel(prev->to_string({ NESTED, 5 }));
         std::string found("&");
-        if (lex < identifier >()) { found += std::string(lexed); }
+        if (lex < identifier >()) {
+          found += std::string(lexed);
+        }
+        std::string sel(seq->hasRealParent() ? "&" : "");
+        if (!seq->empty()) { sel = seq->last()->to_string({ NESTED, 5 }); }
         // ToDo: parser should throw parser exceptions
         error("Invalid CSS after \"" + sel + "\": expected \"{\", was \"" + found + "\"\n\n"
           "\"" + found + "\" may only be used at the beginning of a compound selector.", state);