https://github.com/manifold-systems/manifold/issues/644

- disambiguate a reference to a property from the implementing class where the property field comes from both the interface and the super class. The property should always resolve through the super class not the interface

manifold-core-parent/manifold/src/main/java/manifold/internal/javac/ManResolve.java

@@ -17,8 +17,11 @@
 package manifold.internal.javac;
 
 import com.sun.tools.javac.api.JavacTrees;
+import com.sun.tools.javac.code.Attribute;
 import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.code.Symbol.ClassSymbol;
 import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.code.Types;
 import com.sun.tools.javac.comp.Annotate;
 import com.sun.tools.javac.comp.Attr;
 import com.sun.tools.javac.comp.AttrContext;
@@ -130,6 +133,58 @@ else if( JreUtil.isJava17orLater() )
     }
   }
 
+  public boolean isAccessible( Env<AttrContext> env, Type site, Symbol sym )
+  {
+    boolean accessible = isAccessible( env, site, sym, false );
+    if( !accessible )
+    {
+      return false;
+    }
+
+    return disambiguatePropertyRef( site, sym );
+  }
+
+  // Here we disambiguate a reference to a property from the implementing class where the property field comes from both
+  // the interface and the super class. The property should always resolve through the super class not the interface.
+  private boolean disambiguatePropertyRef( Type site, Symbol sym )
+  {
+    if( sym instanceof Symbol.VarSymbol && sym.owner.isInterface() &&  // property sym is directly an interface member, not impl on a class
+        site.tsym instanceof ClassSymbol && !site.tsym.isInterface() ) // site sym is a class, not an interface
+    {
+      ClassSymbol siteSym = (ClassSymbol)site.tsym;
+      if( siteSym.getSuperclass() != null ) // site type has a superclass
+      {
+        Types types = Types.instance( JavacPlugin.instance().getContext() );
+        if( types.isSubtype( siteSym.getSuperclass(), sym.owner.type ) ) // site type implements interface
+        {
+        if( !hasAnnotation( sym, "manifold.ext.props.rt.api.Static" ) &&
+            (hasAnnotation( sym, "manifold.ext.props.rt.api.get" ) ||
+             hasAnnotation( sym, "manifold.ext.props.rt.api.set" ) ||
+             hasAnnotation( sym, "manifold.ext.props.rt.api.val" ) ||
+             hasAnnotation( sym, "manifold.ext.props.rt.api.var" )) )
+          {
+            // should always access through super class, not interface
+            return false;
+          }
+        }
+      }
+    }
+    return true;
+  }
+
+  private boolean hasAnnotation( Symbol sym, String anno )
+  {
+    for( Attribute.Compound a : sym.getAnnotationMirrors() )
+    {
+      String fqn = a.type.tsym.getQualifiedName().toString();
+      if( fqn.equals( anno ) )
+      {
+        return true;
+      }
+    }
+    return false;
+  }
+
   /**
    * Allow augmented classes to access modules as if defined in both the extended class' module and
    * the extension class' module.