[NF] Fix handling of duplicate outer elements.

Belonging to [master]:
  - #2073
  - OpenModelica/OpenModelica-testsuite#803

Author: perost

Compiler/NFFrontEnd/NFClass.mo

@@ -292,21 +292,25 @@ uniontype Class
     input Class cls2;
     output Boolean identical = false;
   algorithm
-    identical := match (cls1, cls2)
-      case (EXPANDED_CLASS(), EXPANDED_CLASS())
-        then Prefixes.isEqual(cls1.prefixes, cls2.prefixes) and
-             ClassTree.isIdentical(cls1.elements, cls2.elements);
-
-      case (INSTANCED_BUILTIN(), INSTANCED_BUILTIN())
-        algorithm
-          if not Type.isEqual(cls1.ty, cls2.ty) then
-            return;
-          end if;
-        then
-          true;
+    if referenceEq(cls1, cls2) then
+      identical := true;
+    else
+      identical := match (cls1, cls2)
+        case (EXPANDED_CLASS(), EXPANDED_CLASS())
+          then Prefixes.isEqual(cls1.prefixes, cls2.prefixes) and
+               ClassTree.isIdentical(cls1.elements, cls2.elements);
+
+        case (INSTANCED_BUILTIN(), INSTANCED_BUILTIN())
+          algorithm
+            if not Type.isEqual(cls1.ty, cls2.ty) then
+              return;
+            end if;
+          then
+            true;
 
-      else true;
-    end match;
+        else true;
+      end match;
+    end if;
   end isIdentical;
 
   function getDimensions

Compiler/NFFrontEnd/NFComponent.mo

@@ -504,22 +504,26 @@ uniontype Component
     input Component comp2;
     output Boolean identical = false;
   algorithm
-    identical := match (comp1, comp2)
-      case (UNTYPED_COMPONENT(), UNTYPED_COMPONENT())
-        algorithm
-          if not Class.isIdentical(InstNode.getClass(comp1.classInst),
-                                   InstNode.getClass(comp2.classInst)) then
-            return;
-          end if;
-
-          if not Binding.isEqual(comp1.binding, comp2.binding) then
-            return;
-          end if;
-        then
-          true;
-
-      else true;
-    end match;
+    if referenceEq(comp1, comp2) then
+      identical := true;
+    else
+      identical := match (comp1, comp2)
+        case (UNTYPED_COMPONENT(), UNTYPED_COMPONENT())
+          algorithm
+            if not Class.isIdentical(InstNode.getClass(comp1.classInst),
+                                     InstNode.getClass(comp2.classInst)) then
+              return;
+            end if;
+
+            if not Binding.isEqual(comp1.binding, comp2.binding) then
+              return;
+            end if;
+          then
+            true;
+
+        else true;
+      end match;
+    end if;
   end isIdentical;
 
   function toString

Compiler/NFFrontEnd/NFInstNode.mo

@@ -981,17 +981,24 @@ uniontype InstNode
   function checkIdentical
     input InstNode node1;
     input InstNode node2;
+  protected
+    InstNode n1 = resolveOuter(node1);
+    InstNode n2 = resolveOuter(node2);
   algorithm
-    () := matchcontinue (node1, node2)
+    if referenceEq(n1, n2) then
+      return;
+    end if;
+
+    () := matchcontinue (n1, n2)
       case (CLASS_NODE(), CLASS_NODE())
-        guard Class.isIdentical(getClass(node1), getClass(node2)) then ();
+        guard Class.isIdentical(getClass(n1), getClass(n2)) then ();
       case (COMPONENT_NODE(), COMPONENT_NODE())
-        guard Component.isIdentical(component(node1), component(node2)) then ();
+        guard Component.isIdentical(component(n1), component(n2)) then ();
       else
         algorithm
           Error.addMultiSourceMessage(Error.DUPLICATE_ELEMENTS_NOT_IDENTICAL,
-            {toString(node1), toString(node2)},
-            {InstNode.info(node1), InstNode.info(node2)});
+            {toString(n1), toString(n2)},
+            {InstNode.info(n1), InstNode.info(n2)});
         then
           fail();
     end matchcontinue;