# No Field Shadowing
# Detects child class fields that shadow parent class fields
id: no-field-shadowing
name: Child Class Fields Should Not Shadow Parent Fields
severity: error
category: maintainability
defect_class: correctness
inline_tier: blocking
language: java

message: "Field '{{NAME}}' should not shadow parent class field"

description: |
  Field shadowing in subclasses causes confusion and bugs when
  accessing fields through polymorphism. Use different names.

  ✅ FIX: Use a different field name

  ```java
  class Parent {
      protected int value;
  }
  class Child extends Parent {
      private int childValue;  // GOOD - different name
  }
  ```

query: |
  (class_declaration
    (extends_clause
      (type_identifier) @PARENT)
    body: (class_body
      (field_declaration
        (variable_declarator
          name: (identifier) @NAME) @FIELD)))

metavars:
  - PARENT
  - NAME
  - FIELD

post_filter: shadows_parent_field

tags:
  - maintainability
  - java
  - confusing

examples:
  bad: |
    class Parent {
        protected int value;
    }
    class Child extends Parent {
        private int value;  // BAD - shadows parent field
    }

  good: |
    class Parent {
        protected int value;
    }
    class Child extends Parent {
        private int childValue;  // GOOD - different name
    }

has_fix: false