Fix implicit member resolution for fields

lynglib/src/commonMain/kotlin/net/sergeych/lyng/obj/ObjRef.kt

@@ -2228,6 +2228,21 @@ class ImplicitThisMemberRef(
     val name: String,
     val atPos: Pos
 ) : ObjRef {
+    private fun resolveInstanceFieldRecord(th: ObjInstance, caller: ObjClass?): ObjRecord? {
+        if (caller == null) return null
+        for (cls in th.objClass.mro) {
+            if (cls.className == "Obj") break
+            val rec = cls.members[name] ?: continue
+            if (rec.isAbstract) continue
+            val decl = rec.declaringClass ?: cls
+            if (!canAccessMember(rec.visibility, decl, caller, name)) continue
+            val key = decl.mangledName(name)
+            th.fieldRecordForKey(key)?.let { return it }
+            th.instanceScope.objects[key]?.let { return it }
+        }
+        return null
+    }
+
     override fun forEachVariable(block: (String) -> Unit) {
         block(name)
     }
@@ -2265,6 +2280,8 @@ class ImplicitThisMemberRef(
                 }
             }
 
+            resolveInstanceFieldRecord(th, caller)?.let { return it }
+
             val key = th.objClass.publicMemberResolution[name] ?: name
             th.fieldRecordForKey(key)?.let { rec ->
                 if ((rec.type == ObjRecord.Type.Field || rec.type == ObjRecord.Type.ConstructorField) && !rec.isAbstract)
@@ -2333,6 +2350,11 @@ class ImplicitThisMemberRef(
                     return
                 }
             }
+
+            resolveInstanceFieldRecord(th, caller)?.let { rec ->
+                scope.assign(rec, name, newValue)
+                return
+            }
         }
 
         // 3) fallback to normal scope resolution