Make getAnnotationNamedModifiers not return bad data

If the annotation does not exist, use the error buffer to return the
message instead of saying an annotation with a weird name exists.

Compiler/Script/CevalScriptBackend.mo

@@ -756,6 +756,7 @@ algorithm
       list<SimpleModelicaParser.ParseTree> parseTree1, parseTree2;
       list<tuple<Diff, list<Token>>> diffs;
       list<tuple<Diff, list<SimpleModelicaParser.ParseTree>>> treeDiffs;
+      SourceInfo info;
 
     case (cache,_,"setClassComment",{Values.CODE(Absyn.C_TYPENAME(path)),Values.STRING(str)},st as GlobalScript.SYMBOLTABLE(ast=p),_)
       equation
@@ -2039,9 +2040,9 @@ algorithm
 
     case (cache,_,"getAnnotationNamedModifiers",{Values.CODE(Absyn.C_TYPENAME(classpath)),Values.STRING(annotationname)},st as GlobalScript.SYMBOLTABLE(ast=p),_)
       equation
-          Absyn.CLASS(_,_,_,_,_,cdef,_) =Interactive.getPathedClassInProgram(classpath,p);
+          Absyn.CLASS(body=cdef,info=info) =Interactive.getPathedClassInProgram(classpath,p);
           annlst= getAnnotationList(cdef);
-          modifiernamelst=getElementArgsModifiers(annlst,annotationname);
+          modifiernamelst=getElementArgsModifiers(annlst,annotationname,Absyn.pathString(classpath),info);
           v1 = ValuesUtil.makeArray(List.map(modifiernamelst, ValuesUtil.makeString));
       then
           (cache,v1,st);
@@ -7854,6 +7855,8 @@ function getElementArgsModifiers
  "@author arun Helper function which parses list of elementargs,annotationname returns the list of modifiers name in the annotation"
     input list<Absyn.ElementArg> inargs;
     input String instring;
+    input String inClass;
+    input SourceInfo info;
     output list<String> outstring;
 algorithm
     outstring:=match(inargs,instring)
@@ -7873,9 +7876,12 @@ algorithm
 
   case((_::eltarglst),name1)
     then
-        getElementArgsModifiers(eltarglst,name1);
+        getElementArgsModifiers(eltarglst,name1,inClass,info);
 
-  case({},_) then {"The searched annotation name not found"};
+  case ({},_)
+    algorithm
+      Error.addSourceMessage(Error.CLASS_ANNOTATION_DOES_NOT_EXIST, {instring, inClass}, info);
+    then {};
  end match;
 end getElementArgsModifiers;