diff --git a/cdlang/src/main/java/de/monticore/cdgen/CDGenTool.java b/cdlang/src/main/java/de/monticore/cdgen/CDGenTool.java
index 0d137d979..ebd1f4276 100644
--- a/cdlang/src/main/java/de/monticore/cdgen/CDGenTool.java
+++ b/cdlang/src/main/java/de/monticore/cdgen/CDGenTool.java
@@ -13,12 +13,14 @@
 import de.monticore.cd4analysis.trafo.CDAssociationCreateFieldsFromAllRoles;
 import de.monticore.cd4analysis.trafo.CDAssociationCreateFieldsFromNavigableRoles;
 import de.monticore.cd4code.CD4CodeMill;
+import de.monticore.cd4code._cocos.CD4CodeCoCoChecker;
 import de.monticore.cd4code._symboltable.ICD4CodeArtifactScope;
 import de.monticore.cd4code._visitor.CD4CodeTraverser;
 import de.monticore.cdbasis.CDBasisMill;
 import de.monticore.cdbasis._ast.ASTCDClass;
 import de.monticore.cdbasis._ast.ASTCDCompilationUnit;
 import de.monticore.cdbasis.trafo.CDBasisDefaultPackageTrafo;
+import de.monticore.cdgen.cocos.CD2JavaGenCoCos;
 import de.monticore.cdinterfaceandenum._ast.ASTCDEnum;
 import de.monticore.cdinterfaceandenum._ast.ASTCDInterface;
 import de.monticore.generating.GeneratorSetup;
@@ -388,7 +390,8 @@ public void runBeforeSTCoCos(ASTCDCompilationUnit ast) {
    * @param ast the original ast
    */
   public void runCoCos(ASTCDCompilationUnit ast) {
-    super.runCoCos(ast);
+    CD4CodeCoCoChecker checker = new CD2JavaGenCoCos().getCheckerForAllCoCos();
+    checker.checkAll(ast);
   }
   
   @Override
diff --git a/cdlang/src/main/java/de/monticore/cdgen/cocos/CD2JavaGenCoCos.java b/cdlang/src/main/java/de/monticore/cdgen/cocos/CD2JavaGenCoCos.java
index 587fe0559..de1da55b1 100644
--- a/cdlang/src/main/java/de/monticore/cdgen/cocos/CD2JavaGenCoCos.java
+++ b/cdlang/src/main/java/de/monticore/cdgen/cocos/CD2JavaGenCoCos.java
@@ -10,8 +10,6 @@ public class CD2JavaGenCoCos extends CD4CodeCoCosDelegator {
   protected void addCheckerForAllCoCos(CD4CodeCoCoChecker checker) {
     super.addCheckerForAllCoCos(checker);
     checker.addCoCo(new CDAssociationUniqueInHierarchy());
-    checker.addCoCo(new CDNoAttributesInInterfaces());
-    checker.addCoCo(new CDNoOutgoingAssocs4Interfaces());
     checker.addCoCo(new CDSingleClassInheritance());
   }
   
diff --git a/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUnique.java b/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUnique.java
index f4144774b..2c302aba6 100644
--- a/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUnique.java
+++ b/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUnique.java
@@ -17,9 +17,6 @@
  */
 public class CDAssociationUnique implements CDBasisASTCDDefinitionCoCo {
   
-  /**
-   * @param node class to check.
-   */
   @Override
   public void check(ASTCDDefinition node) {
     
@@ -37,40 +34,44 @@ public void check(ASTCDDefinition node) {
           
           // if they share a left role-name, the referenced types on the right should not be the
           // same
-          if (deriveRoleName(assoc1, AssocSide.LEFT).equals(deriveRoleName(assoc2,
-              AssocSide.LEFT))) {
-            checkRef(node, findTypeByFullName(assoc1, assoc1.getRightQualifiedName().getQName()),
-                findTypeByFullName(assoc2, assoc2.getRightQualifiedName().getQName()), assoc1);
+          if (deriveRoleName(assoc1, AssocSide.LEFT).equals(deriveRoleName(assoc2, AssocSide.LEFT))
+              && assoc1.getCDAssocDir().isDefinitiveNavigableLeft() && assoc2.getCDAssocDir()
+                  .isDefinitiveNavigableLeft()) {
+            checkRef(assoc1, assoc2, findTypeByFullName(assoc1, assoc1.getRightQualifiedName()
+                .getQName()), findTypeByFullName(assoc2, assoc2.getRightQualifiedName()
+                    .getQName()));
           }
           
           // if they share a right role-name, the referenced types on the left should not be the
           // same
           if (deriveRoleName(assoc1, AssocSide.RIGHT).equals(deriveRoleName(assoc2,
-              AssocSide.RIGHT))) {
-            checkRef(node, findTypeByFullName(assoc1, assoc1.getLeftQualifiedName().getQName()),
-                findTypeByFullName(assoc2, assoc2.getLeftQualifiedName().getQName()), assoc1);
+              AssocSide.RIGHT)) && assoc1.getCDAssocDir().isDefinitiveNavigableRight() && assoc2
+                  .getCDAssocDir().isDefinitiveNavigableRight()) {
+            checkRef(assoc1, assoc2, findTypeByFullName(assoc1, assoc1.getLeftQualifiedName()
+                .getQName()), findTypeByFullName(assoc2, assoc2.getLeftQualifiedName().getQName()));
           }
           
           // We also consider a left-to-right role name match ...
-          if (deriveRoleName(assoc1, AssocSide.LEFT).equals(deriveRoleName(assoc2,
-              AssocSide.RIGHT))) {
-            checkRef(node, findTypeByFullName(assoc1, assoc1.getRightQualifiedName().getQName()),
-                findTypeByFullName(assoc2, assoc2.getLeftQualifiedName().getQName()), assoc1);
+          if (deriveRoleName(assoc1, AssocSide.LEFT).equals(deriveRoleName(assoc2, AssocSide.RIGHT))
+              && assoc1.getCDAssocDir().isDefinitiveNavigableLeft() && assoc2.getCDAssocDir()
+                  .isDefinitiveNavigableRight()) {
+            checkRef(assoc1, assoc2, findTypeByFullName(assoc1, assoc1.getRightQualifiedName()
+                .getQName()), findTypeByFullName(assoc2, assoc2.getLeftQualifiedName().getQName()));
           }
           // ... as well as a right-to-left match
-          if (deriveRoleName(assoc1, AssocSide.RIGHT).equals(deriveRoleName(assoc2,
-              AssocSide.LEFT))) {
-            checkRef(node, findTypeByFullName(assoc1, assoc1.getLeftQualifiedName().getQName()),
-                findTypeByFullName(assoc2, assoc2.getRightQualifiedName().getQName()), assoc1);
+          if (deriveRoleName(assoc1, AssocSide.RIGHT).equals(deriveRoleName(assoc2, AssocSide.LEFT))
+              && assoc1.getCDAssocDir().isDefinitiveNavigableRight() && assoc2.getCDAssocDir()
+                  .isDefinitiveNavigableLeft()) {
+            checkRef(assoc1, assoc2, findTypeByFullName(assoc1, assoc1.getLeftQualifiedName()
+                .getQName()), findTypeByFullName(assoc2, assoc2.getRightQualifiedName()
+                    .getQName()));
           }
         }
       }
     }
   }
   
-  /**
-   * helper-method to find types by full-name
-   */
+  /** helper-method to find types by full-name */
   protected ASTCDType findTypeByFullName(ASTCDAssociation node, String fullName) {
     
     Optional<CDTypeSymbol> optSymbol = node.getEnclosingScope().resolveCDType(fullName);
@@ -78,18 +79,20 @@ protected ASTCDType findTypeByFullName(ASTCDAssociation node, String fullName) {
       return optSymbol.get().getAstNode();
     }
     
-    Log.error("0xCDCE2: Could not find: " + fullName + ".");
+    Log.error("0xCDCE2: Could not find: " + fullName + ".", node.get_SourcePositionStart());
     return null;
   }
   
   /** Check if type2 is the same as type1. */
-  protected void checkRef(ASTCDDefinition node, ASTCDType type1, ASTCDType type2,
-      ASTCDAssociation assoc1) {
+  protected void checkRef(ASTCDAssociation assoc1, ASTCDAssociation assoc2, ASTCDType type1,
+      ASTCDType type2) {
     if (type1.equals(type2)) {
-      Log.error(String.format("0xCDCE1: %s has a duplicate association to %s", type1.getName(),
-          type2.getName()), assoc1.isPresent_SourcePositionStart() ? assoc1
-              .get_SourcePositionStart() : null, assoc1.isPresent_SourcePositionEnd() ? assoc1
-                  .get_SourcePositionEnd() : null);
+      Log.error(String.format("0xCDCE1: %s has duplicate associations %s at %s and %s, "
+          + "i.e. 2 different associations with the same target role-name for a given source-type."
+          + "This may lead to conflicts in the generated code and is therefore not permitted "
+          + "for code generation purposes.", type1.getName(), assoc1.getPrintableName(), assoc1
+              .get_SourcePositionStart(), assoc2.get_SourcePositionStart()), assoc2
+                  .get_SourcePositionStart());
     }
   }
   
@@ -114,7 +117,7 @@ else if (assoc.isPresentName()) {
     }
   }
   
-  private enum AssocSide {
+  protected enum AssocSide {
     LEFT, RIGHT;
   }
   
diff --git a/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUniqueInHierarchy.java b/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUniqueInHierarchy.java
index 60921f77b..66d0d8fc2 100644
--- a/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUniqueInHierarchy.java
+++ b/cdlang/src/main/java/de/monticore/cdgen/cocos/CDAssociationUniqueInHierarchy.java
@@ -2,7 +2,6 @@
 package de.monticore.cdgen.cocos;
 
 import de.monticore.cdassociation._ast.ASTCDAssociation;
-import de.monticore.cdbasis._ast.ASTCDDefinition;
 import de.monticore.cdbasis._ast.ASTCDType;
 import de.monticore.symbols.basicsymbols._symboltable.TypeSymbol;
 import de.se_rwth.commons.logging.Log;
@@ -16,16 +15,17 @@
 public class CDAssociationUniqueInHierarchy extends CDAssociationUnique {
   
   @Override
-  protected void checkRef(ASTCDDefinition node, ASTCDType type1, ASTCDType type2,
-      ASTCDAssociation assoc1) {
-    super.checkRef(node, type1, type2, assoc1);
+  protected void checkRef(ASTCDAssociation assoc1, ASTCDAssociation assoc2, ASTCDType type1,
+      ASTCDType type2) {
+    super.checkRef(assoc1, assoc2, type1, type2);
     // We now also check if the types are in a sub/super-type relation
-    checkSuper(type1, type2);
-    checkSuper(type2, type1);
+    checkSuper(assoc1, assoc2, type1, type2);
+    checkSuper(assoc2, assoc1, type2, type1);
   }
   
   /** Check if type2 is a super-type of type1. */
-  protected void checkSuper(ASTCDType type1, ASTCDType type2) {
+  protected void checkSuper(ASTCDAssociation assoc1, ASTCDAssociation assoc2, ASTCDType type1,
+      ASTCDType type2) {
     
     Stack<TypeSymbol> typesToVisit = new Stack<>();
     
@@ -38,8 +38,10 @@ protected void checkSuper(ASTCDType type1, ASTCDType type2) {
     while (!typesToVisit.isEmpty()) {
       final TypeSymbol nextType = typesToVisit.pop();
       if (nextType.getFullName().equals(type2.getSymbol().getFullName())) {
-        Log.error(String.format("0xCDCE6: %s redefines an association of %s.", type1.getName(),
-            type2.getName()));
+        Log.error(String.format("0xCDCE6: %s redefines an association of %s from %s at %s."
+            + "Redefining associations are not supported by code generators.", type1.getName(),
+            type2.getName(), assoc2.get_SourcePositionStart(), assoc1.get_SourcePositionStart()),
+            assoc1.get_SourcePositionStart());
         return;
       }
       
diff --git a/cdlang/src/test/java/de/monticore/cdgen/cocos/CDAssociationUniqueTest.java b/cdlang/src/test/java/de/monticore/cdgen/cocos/CDAssociationUniqueTest.java
index bf2ce95dd..cb144640f 100644
--- a/cdlang/src/test/java/de/monticore/cdgen/cocos/CDAssociationUniqueTest.java
+++ b/cdlang/src/test/java/de/monticore/cdgen/cocos/CDAssociationUniqueTest.java
@@ -56,4 +56,60 @@ public void testUniqueAssocName() throws IOException {
     runTest(model, false);
   }
   
+  @Test
+  public void testOnlyNavigable() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association A -> (r) B;" + "}";
+    runTest(model, false);
+  }
+  
+  @Test
+  public void testOnlyNavigableReverse() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association B (r) <- A;" + "}";
+    runTest(model, false);
+  }
+  
+  @Test
+  public void testOpposedAssocs() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association A <- B;" + "}";
+    runTest(model, false);
+  }
+  
+  @Test
+  public void testOpposedAssocs2() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association B -> A;" + "}";
+    runTest(model, false);
+  }
+  
+  @Test
+  public void testNonOpposedAssocs() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association A <-> B;" + "}";
+    runTestForErrorCode(model, ERROR_CODE);
+  }
+  
+  @Test
+  public void testNonOpposedAssocs2() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association A <-> B;" + "}";
+    runTestForErrorCode(model, ERROR_CODE);
+  }
+  
+  @Test
+  public void testNonOpposedAssocs3() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association B <- A;" + "}";
+    runTestForErrorCode(model, ERROR_CODE);
+  }
+  
+  @Test
+  public void testNonOpposedAssocsUnspecified() throws IOException {
+    String model = "classdiagram DuplicateAssocs {" + "  class A; class B;"
+        + "  association A -> B;" + "  association A -- B;" + "}";
+    runTest(model, false);
+  }
+  
 }