Add tests and fix the function that was copied over

Author: jseminck

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

@@ -11,6 +11,7 @@ const has = require('has');
 const Components = require('../util/Components');
 const variable = require('../util/variable');
 const annotations = require('../util/annotations');
+const versionUtil = require('../util/version');
 
 // ------------------------------------------------------------------------------
 // Constants
@@ -134,17 +135,23 @@ module.exports = {
     }
 
     /**
-     * Resolve the type annotation for a given node.
-     * Flow annotations are sometimes wrapped in outer `TypeAnnotation`
-     * and `NullableTypeAnnotation` nodes which obscure the annotation we're
-     * interested in.
-     * This method also resolves type aliases where possible.
+     * Resolve the type annotation for a given class declaration node with superTypeParameters.
      *
      * @param {ASTNode} node The annotation or a node containing the type annotation.
      * @returns {ASTNode} The resolved type annotation for the node.
      */
-    function resolveTypeAnnotation(node) {
-      let annotation = node.typeAnnotation || node;
+    function resolveSuperParameterPropsType(node) {
+      let propsParameterPosition;
+      try {
+        // Flow <=0.52 had 3 required TypedParameters of which the second one is the Props.
+        // Flow >=0.53 has 2 optional TypedParameters of which the first one is the Props.
+        propsParameterPosition = versionUtil.testFlowVersion(context, '0.53.0') ? 0 : 1;
+      } catch (e) {
+        // In case there is no flow version defined, we can safely assume that when there are 3 Props we are dealing with version <= 0.52
+        propsParameterPosition = node.superTypeParameters.params.length <= 2 ? 0 : 1;
+      }
+
+      let annotation = node.superTypeParameters.params[propsParameterPosition];
       while (annotation && (annotation.type === 'TypeAnnotation' || annotation.type === 'NullableTypeAnnotation')) {
         annotation = annotation.typeAnnotation;
       }

lib/rules/prop-types.js

@@ -12,6 +12,7 @@ const Components = require('../util/Components');
 const variable = require('../util/variable');
 const annotations = require('../util/annotations');
 const versionUtil = require('../util/version');
+
 // ------------------------------------------------------------------------------
 // Constants
 // ------------------------------------------------------------------------------

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

@@ -2069,6 +2069,30 @@ ruleTester.run('no-unused-prop-types', rule, {
       };
     `,
       parser: 'babel-eslint'
+    }, {
+      code: `
+        type Person = {
+          firstname: string
+        }
+        class MyComponent extends React.Component<void, Props, void> {
+          render() {
+            return <div>Hello {this.props.firstname}</div>
+          }
+        }
+      `,
+      parser: 'babel-eslint'
+    }, {
+      code: `
+        type Person = {
+          firstname: string
+        }
+        class MyComponent extends React.Component<Props> {
+          render() {
+            return <div>Hello {this.props.firstname}</div>
+          }
+        }
+      `,
+      parser: 'babel-eslint'
     }
   ],
 
@@ -3469,6 +3493,22 @@ ruleTester.run('no-unused-prop-types', rule, {
       errors: [{
         message: '\'aProp\' PropType is defined but prop is never used'
       }]
+    }, {
+      code: `
+        type Props = {
+          firstname: string,
+          lastname: string,
+        }
+        class MyComponent extends React.Component<void, Props, void> {
+          render() {
+            return <div>Hello {this.props.firstname}</div>
+          }
+        }
+      `,
+      parser: 'babel-eslint',
+      errors: [{
+        message: '\'lastname\' PropType is defined but prop is never used'
+      }]
     }
 
     /* , {