[Fix] prop-types/propTypes: follow a returned identifier to see if it is JSX

Fixes #1046

Author: ljharb

CHANGELOG.md

@@ -18,6 +18,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 * `propTypes`: Handle TSTypeReference in no-unused-prop-type ([#3195][] @niik)
 * [`sort-prop-types`]: avoid repeated warnings of the same node/reason ([#519][] @ljharb)
 * [`jsx-indent`]: Fix indent handling for closing parentheses ([#620][] @stefanbuck])
+* [`prop-types`/`propTypes`]: follow a returned identifier to see if it is JSX ([#1046][] @ljharb)
 
 ### Changed
 * [readme] change [`jsx-runtime`] link from branch to sha ([#3160][] @tatsushitoji)
@@ -41,6 +42,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 [#3133]: https://github.com/yannickcr/eslint-plugin-react/pull/3133
 [#2921]: https://github.com/yannickcr/eslint-plugin-react/pull/2921
 [#2753]: https://github.com/yannickcr/eslint-plugin-react/pull/2753
+[#1046]: https://github.com/yannickcr/eslint-plugin-react/issues/1046
 [#620]: https://github.com/yannickcr/eslint-plugin-react/pull/620
 [#519]: https://github.com/yannickcr/eslint-plugin-react/issues/519
 

lib/util/jsx.js

@@ -8,6 +8,7 @@ const estraverse = require('estraverse');
 const elementType = require('jsx-ast-utils/elementType');
 
 const astUtil = require('./ast');
+const variableUtil = require('./variable');
 
 // See https://github.com/babel/babel/blob/ce420ba51c68591e057696ef43e028f41c6e04cd/packages/babel-types/src/validators/react/isCompatTag.js
 // for why we only test for the first character
@@ -125,7 +126,8 @@ function isReturningJSX(isCreateElement, ASTnode, context, strict, ignoreNull) {
             break;
           case 'JSXElement':
           case 'JSXFragment':
-            setFound(); break;
+            setFound();
+            break;
           case 'CallExpression':
             if (isCreateElement(childNode)) {
               setFound();
@@ -137,6 +139,13 @@ function isReturningJSX(isCreateElement, ASTnode, context, strict, ignoreNull) {
               setFound();
             }
             break;
+          case 'Identifier': {
+            const variable = variableUtil.findVariableByName(context, childNode.name);
+            if (isJSX(variable)) {
+              setFound();
+            }
+            break;
+          }
           default:
         }
       },

tests/lib/rules/prop-types.js

@@ -7624,6 +7624,33 @@ ruleTester.run('prop-types', rule, {
         },
       ],
       features: ['ts', 'no-babel'],
+    },
+    {
+      code: `
+        const Foo = ({ foo }) => {
+          return <SomeJSX />;
+        }
+      `,
+      errors: [
+        {
+          messageId: 'missingPropType',
+          data: { name: 'foo' },
+        },
+      ],
+    },
+    {
+      code: `
+        const Foo = ({ foo }) => {
+          const returnValue = <SomeJSX />;
+          return returnValue;
+        }
+      `,
+      errors: [
+        {
+          messageId: 'missingPropType',
+          data: { name: 'foo' },
+        },
+      ],
     }
   )),
 });

tests/util/jsx.js

@@ -20,7 +20,16 @@ const parseCode = (code) => {
   return ASTnode.body[0];
 };
 
-const mockContext = {};
+const mockContext = {
+  getScope() {
+    return {
+      type: 'global',
+      upper: null,
+      childScopes: [],
+      variables: [],
+    };
+  },
+};
 
 describe('jsxUtil', () => {
   describe('isReturningJSX', () => {