Fix no-unused-prop-types crash with Flow spread operator (fixes #1178

Author: yannickcr

lib/rules/no-unused-prop-types.js

@@ -678,6 +678,10 @@ module.exports = {
       switch (propTypes && propTypes.type) {
         case 'ObjectTypeAnnotation':
           iterateProperties(propTypes.properties, function(key, value) {
+            if (!value) {
+              ignorePropsValidation = true;
+              return;
+            }
             var types = buildTypeAnnotationDeclarationTypes(value, key);
             if (types === true) {
               types = {};

tests/lib/rules/no-unused-prop-types.js

@@ -1411,6 +1411,34 @@ ruleTester.run('no-unused-prop-types', rule, {
         '  bar: PropTypes.bool',
         '};'
       ].join('\n')
+    }, {
+      code: [
+        'type Person = {',
+        '  ...data,',
+        '  lastname: string',
+        '};',
+        'class Hello extends React.Component {',
+        '  props: Person;',
+        '  render () {',
+        '    return <div>Hello {this.props.firstname}</div>;',
+        '  }',
+        '}'
+      ].join('\n'),
+      parser: 'babel-eslint'
+    }, {
+      code: [
+        'type Person = {|',
+        '  ...data,',
+        '  lastname: string',
+        '|};',
+        'class Hello extends React.Component {',
+        '  props: Person;',
+        '  render () {',
+        '    return <div>Hello {this.props.firstname}</div>;',
+        '  }',
+        '}'
+      ].join('\n'),
+      parser: 'babel-eslint'
     }
   ],