reordering of components is allowed

src/main/jastadd/Analysis.jrag

@@ -62,12 +62,6 @@ aspect ComponentAnalysis {
   eq Program.getChild().lookupComponent(TypeDecl td, String name)
     = lookupComponentSyn(td, name);
   syn Component Program.lookupComponentSyn(TypeDecl td, String name) {
-    // Check super type first to find duplicates (shadowing is not allowed)
-    if (td.hasSuper() && td.getSuper().decl() != null) {
-      Component c = lookupComponentSyn(td.getSuper().decl(), name);
-      if (c != null) return c;
-    }
-
     for (Component c: td.getComponents()) {
       if (c.name().equals(name)) {
         return c;
@@ -84,6 +78,36 @@ aspect ComponentAnalysis {
     return null;
   }
 
+  syn boolean Component.isInvalidRedefinition() {
+    if (toTypeDecl() == null) return false;
+
+    TypeDecl td = toTypeDecl();
+
+    while (td.hasSuper() && td.getSuper().decl() != null) {
+      td = td.getSuper().decl();
+      Component c = lookupComponent(td, getID());
+      if (c != null && isTargetOfDirectedRelation()) return true;
+
+      if (c != null && !this.isEqual(c)) return true;
+    }
+    return false;
+  }
+
+  syn boolean Component.isEqual(Component c) = this.getClass() == c.getClass() && getTypeUse().isEqual(c.getTypeUse());
+
+  syn boolean TypeUse.isEqual(TypeUse u);
+  eq SimpleTypeUse.isEqual(TypeUse u) = u instanceof SimpleTypeUse && getID().equals(u.getID());
+  eq ParameterizedTypeUse.isEqual(TypeUse u) {
+    if (!getID().equals(u.getID())) return false;
+    if (!(u instanceof ParameterizedTypeUse)) return false;
+    ParameterizedTypeUse pu = (ParameterizedTypeUse) u;
+    if (getNumTypeUse() != pu.getNumTypeUse()) return false;
+    for (int i = 0; i < getNumTypeUse(); i++) {
+      if (!getTypeUse(i).isEqual(pu.getTypeUse(i))) return false;
+    }
+    return true;
+  }
+
   syn RelationComponent RelationComponent.lookup(TypeDecl td, String name)
     = !isTargetOfDirectedRelation() && toTypeDecl() == td && name().equals(name)
     ? this

src/main/jastadd/Errors.jrag

@@ -20,6 +20,11 @@ aspect Errors {
     when isAlreadyDeclared()
     to Program.errors();
 
+  Component contributes error("Component '" + name()
+    + "' is an invalid redefition for type '" + toTypeDecl() + "'")
+    when isInvalidRedefinition()
+    to Program.errors();
+
   RelationComponent contributes
     error("Role name missing for type '" + toTypeDecl() + "'")
     when !isTargetOfDirectedRelation() && name().isEmpty()

src/test/jastadd/errors/Inheritance.expected

 Errors:
-$FILENAME Line 2, column 12: Component 'X' is already declared for type 'B1'
-$FILENAME Line 6, column 5: Component 'X' is already declared for type 'B2'
+$FILENAME Line 4, column 12: Component 'X' is an invalid redefition for type 'B3'
+$FILENAME Line 7, column 5: Component 'X' is an invalid redefition for type 'B2'

src/test/jastadd/errors/Inheritance.relast

 A ::= X;
 B1 : A ::= X;
 B2 : A;
+B3 : A ::= <X:String>;
 X;
 
 rel B2.X -> X;

src/test/jastadd/errors/InheritanceLeft.expected

 Errors:
-$FILENAME Line 2, column 12: Component 'X' is already declared for type 'B1'
-$FILENAME Line 6, column 10: Component 'X' is already declared for type 'B2'
+$FILENAME Line 4, column 12: Component 'X' is an invalid redefition for type 'B3'
+$FILENAME Line 7, column 10: Component 'X' is an invalid redefition for type 'B2'

src/test/jastadd/errors/InheritanceLeft.relast

 A ::= X;
 B1 : A ::= X;
 B2 : A;
+B3 : A ::= <X:String>;
 X;
 
 rel X <- B2.X;