diff --git a/sources/zweic/Analyzer.scala b/sources/zweic/Analyzer.scala
index 741106d..7a3001d 100755
--- a/sources/zweic/Analyzer.scala
+++ b/sources/zweic/Analyzer.scala
@@ -36,7 +36,7 @@
 	case ClassDef(name, None, members) =>
 	  classScope.get(name.name) match  {
 		case Some(c) =>
-		  Report.error(tree.pos, "Class already defined: " + name.name)
+		  Report.error(tree.pos, "Class already defined: " + name)
 		case None => 
 		  val cs = ClassSymbol(tree.pos, name.name, None);
 		  classScope(name.name) = cs;
@@ -45,7 +45,7 @@
 	case ClassDef(name, extend, members) =>
 	  classScope.get(name.name) match {
 		case Some(c) =>
-		  Report.error(tree.pos, "Class already defined: " + name.name);
+		  Report.error(tree.pos, "Class already defined: " + name);
 		case None =>
 		  val cs = ClassSymbol(tree.pos, name.name, classScope.get(extend.get.name));
 		  classScope(name.name) = cs;
@@ -58,16 +58,34 @@
   private def analyzeMember(ownerClass: ClassSymbol, tree: Member): Unit = 
 	tree.match {
 		case FieldDecl(Formal(name, typ)) =>
-			// TODO check that field does not yet exist!
-			ownerClass.enterField(FieldSymbol(tree.pos, name.name, analyzeType(typ)))
+			ownerClass.lookupField(name.name) match {
+				case Some(v) =>
+					Report.error(tree.pos, "Class variable already defined: " + name);
+				case None =>
+					name.sym= FieldSymbol(tree.pos, name.name, analyzeType(typ));
+					ownerClass.enterField(name.sym.asInstanceOf[FieldSymbol]);
+			}
 		case MethodDef(name, args, rtype, expr) =>
+			var myVarScope = emptyVarScope;
+
+			for ( val x <- ownerClass.allFields ) myVarScope = myVarScope + x.name -> x.asInstanceOf[VarSymbol];
+
+			val paramtypes = for ( val f <- args ) yield {
+				//TODO: check that there isn't already a class field with the same name
+				f.name.sym = VarSymbol(f.pos, f.name.name, analyzeType(f.typ));
+				myVarScope = myVarScope + f.name.name -> f.name.sym.asInstanceOf[VarSymbol];
+				analyzeType(f.typ);
+			}
+
+			val rt = analyzeType(rtype);
+			checkSubtype(tree.pos, "Return type mismatch", analyzeExpr(myVarScope, expr), rt);
+			name.sym = MethodSymbol(tree.pos, name.name, paramtypes, rt);
+
 			ownerClass.lookupMethod(name.name) match {
 				case Some(m) =>
-				  var paramtypes = for ( val Formal(x,y) <- args ) yield analyzeType(y);
-				  ownerClass.enterMethod(MethodSymbol(tree.pos, name.name, paramtypes, analyzeType(rtype)))
+				  ownerClass.enterMethod(name.sym.asInstanceOf[MethodSymbol]);
 				case None =>
-				  var paramtypes = for ( val Formal(x,y) <- args ) yield analyzeType(y);
-				  ownerClass.enterNewMethod(MethodSymbol(tree.pos, name.name, paramtypes, analyzeType(rtype)))
+				  ownerClass.enterNewMethod(name.sym.asInstanceOf[MethodSymbol]);
 			}
   }
 
@@ -88,9 +106,8 @@
 			case None =>
 				val mt = analyzeType(typ);
 				checkSubtype(tree.pos, "Incompatible types", analyzeExpr(varScope, expr), mt);
-				val ms = VarSymbol(tree.pos, name.name, mt);
-				name.sym = ms;
-				varScope + name.name -> ms;
+				name.sym = VarSymbol(tree.pos, name.name, mt);
+				varScope + name.name -> name.sym.asInstanceOf[VarSymbol];
 		}
 
 	case Set(ident, expr) =>