Handle comparison of empty expressions

Author: sjoelund

Compiler/FrontEnd/Expression.mo

@@ -12940,6 +12940,11 @@ algorithm
         DAE.SHARED_LITERAL(index = i) := inExp2;
       then Util.intCompare(inExp1.index, i);
 
+    case DAE.EMPTY()
+      algorithm
+        DAE.EMPTY(name=cr) := inExp2;
+      then ComponentReference.crefCompareGeneric(inExp1.name, cr);
+
     else
       algorithm
         Error.addInternalError("Expression.compare failed: ctor:" + String(valueConstructor(inExp1)) + " " + printExpStr(inExp1) + " " + printExpStr(inExp2), sourceInfo());

Compiler/FrontEnd/InstSection.mo

@@ -3071,6 +3071,10 @@ algorithm
       then
         fail();
 
+    // Failed in graphics mode; just continue
+    case (cache,env,ih,sets,_,_,_,_,graph) guard Config.getGraphicsExpMode()
+      then (cache,env,ih,sets,DAE.emptyDae,graph);
+
     case (_,_,_,_,_,c1,c2,_,_)
       equation
         true = Flags.isSet(Flags.FAILTRACE);