Fix hasOwnProperty that is taken for a prop (fixes #102)

Author: yannickcr

lib/rules/prop-types.js

@@ -126,6 +126,10 @@ module.exports = function(context) {
 
     switch (type) {
       case 'direct':
+        // Ignore Object methods
+        if (Object.prototype[node.parent.property.name]) {
+          break;
+        }
         usedPropTypes.push({
           name: node.parent.property.name,
           node: node.parent.property

tests/lib/rules/prop-types.js

@@ -235,6 +235,24 @@ eslintTester.addRuleTest('lib/rules/prop-types', {
         classes: true,
         jsx: true
       }
+    }, {
+      code: [
+        'class Hello extends React.Component {',
+        '  render() {',
+        '    if (this.props.hasOwnProperty(\'firstname\')) {',
+        '      return <div>Hello {this.props.firstname}</div>;',
+        '    }',
+        '    return <div>Hello</div>;',
+        '  }',
+        '}',
+        'Hello.propTypes = {',
+        '  \'firstname\': React.PropTypes.string',
+        '};'
+      ].join('\n'),
+      ecmaFeatures: {
+        classes: true,
+        jsx: true
+      }
     }
   ],