From be2777c5338669836d786f9a7806f499fd566dcd Mon Sep 17 00:00:00 2001
From: Risto Keravuori <risto.k@mac.com>
Date: Thu, 9 Nov 2023 20:33:58 -0800
Subject: [PATCH] fix(eslint-plugin): [explicit-function-return-type] support
 JSX attributes in `allowTypedFunctionExpressions` (#7553)

---
 .../rules/explicit-function-return-type.md    |   4 +
 .../src/util/explicitReturnTypeUtils.ts       |  77 ++++++----
 .../explicit-function-return-type.test.ts     | 137 ++++++++++++++++++
 3 files changed, 190 insertions(+), 28 deletions(-)

diff --git a/packages/eslint-plugin/docs/rules/explicit-function-return-type.md b/packages/eslint-plugin/docs/rules/explicit-function-return-type.md
index 3332f1d77ef..6aa1e621314 100644
--- a/packages/eslint-plugin/docs/rules/explicit-function-return-type.md
+++ b/packages/eslint-plugin/docs/rules/explicit-function-return-type.md
@@ -172,6 +172,10 @@ functionWithObjectArg({
     return 1;
   },
 });
+
+const Comp: FC = () => {
+  return <button onClick={() => {}} />;
+};
 ```
 
 ### `allowHigherOrderFunctions`
diff --git a/packages/eslint-plugin/src/util/explicitReturnTypeUtils.ts b/packages/eslint-plugin/src/util/explicitReturnTypeUtils.ts
index a47b101e07c..64f85d48b75 100644
--- a/packages/eslint-plugin/src/util/explicitReturnTypeUtils.ts
+++ b/packages/eslint-plugin/src/util/explicitReturnTypeUtils.ts
@@ -37,6 +37,53 @@ function isPropertyDefinitionWithTypeAnnotation(
   );
 }
 
+/**
+ * Checks if a node belongs to:
+ * ```
+ * foo(() => 1)
+ * ```
+ */
+function isFunctionArgument(
+  parent: TSESTree.Node,
+  callee?: FunctionExpression,
+): parent is TSESTree.CallExpression {
+  return (
+    parent.type === AST_NODE_TYPES.CallExpression &&
+    // make sure this isn't an IIFE
+    parent.callee !== callee
+  );
+}
+
+/**
+ * Checks if a node is type-constrained in JSX
+ * ```
+ * <Foo x={() => {}} />
+ * <Bar>{() => {}}</Bar>
+ * <Baz {...props} />
+ * ```
+ */
+function isTypedJSX(
+  node: TSESTree.Node,
+): node is TSESTree.JSXExpressionContainer | TSESTree.JSXSpreadAttribute {
+  return (
+    node.type === AST_NODE_TYPES.JSXExpressionContainer ||
+    node.type === AST_NODE_TYPES.JSXSpreadAttribute
+  );
+}
+
+function isTypedParent(
+  parent: TSESTree.Node,
+  callee?: FunctionExpression,
+): boolean {
+  return (
+    isTypeAssertion(parent) ||
+    isVariableDeclaratorWithTypeAnnotation(parent) ||
+    isPropertyDefinitionWithTypeAnnotation(parent) ||
+    isFunctionArgument(parent, callee) ||
+    isTypedJSX(parent)
+  );
+}
+
 /**
  * Checks if a node belongs to:
  * ```
@@ -78,13 +125,7 @@ function isPropertyOfObjectWithType(
     return false;
   }
 
-  return (
-    isTypeAssertion(parent) ||
-    isPropertyDefinitionWithTypeAnnotation(parent) ||
-    isVariableDeclaratorWithTypeAnnotation(parent) ||
-    isFunctionArgument(parent) ||
-    isPropertyOfObjectWithType(parent)
-  );
+  return isTypedParent(parent) || isPropertyOfObjectWithType(parent);
 }
 
 /**
@@ -127,23 +168,6 @@ function doesImmediatelyReturnFunctionExpression({
   );
 }
 
-/**
- * Checks if a node belongs to:
- * ```
- * foo(() => 1)
- * ```
- */
-function isFunctionArgument(
-  parent: TSESTree.Node,
-  callee?: FunctionExpression,
-): parent is TSESTree.CallExpression {
-  return (
-    parent.type === AST_NODE_TYPES.CallExpression &&
-    // make sure this isn't an IIFE
-    parent.callee !== callee
-  );
-}
-
 /**
  * Checks if a function belongs to:
  * ```
@@ -194,11 +218,8 @@ function isTypedFunctionExpression(
   }
 
   return (
-    isTypeAssertion(parent) ||
-    isVariableDeclaratorWithTypeAnnotation(parent) ||
-    isPropertyDefinitionWithTypeAnnotation(parent) ||
+    isTypedParent(parent, node) ||
     isPropertyOfObjectWithType(parent) ||
-    isFunctionArgument(parent, node) ||
     isConstructorArgument(parent)
   );
 }
diff --git a/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts b/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts
index 0036b5f94d9..eedbd9b76c7 100644
--- a/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts
+++ b/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts
@@ -180,6 +180,53 @@ class App {
       `,
       options: [{ allowTypedFunctionExpressions: true }],
     },
+    // https://github.com/typescript-eslint/typescript-eslint/issues/7552
+    {
+      code: 'const foo = <button onClick={() => {}} />;',
+      options: [{ allowTypedFunctionExpressions: true }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    {
+      code: 'const foo = <button on={{ click: () => {} }} />;',
+      options: [{ allowTypedFunctionExpressions: true }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    {
+      code: 'const foo = <Bar>{() => {}}</Bar>;',
+      options: [{ allowTypedFunctionExpressions: true }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    {
+      code: 'const foo = <Bar>{{ on: () => {} }}</Bar>;',
+      options: [{ allowTypedFunctionExpressions: true }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    {
+      code: 'const foo = <button {...{ onClick: () => {} }} />;',
+      options: [{ allowTypedFunctionExpressions: true }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+
     // https://github.com/typescript-eslint/typescript-eslint/issues/525
     {
       code: `
@@ -977,6 +1024,96 @@ const x: Foo = {
         },
       ],
     },
+    {
+      code: 'const foo = <button onClick={() => {}} />;',
+      options: [{ allowTypedFunctionExpressions: false }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 1,
+          endLine: 1,
+          column: 33,
+          endColumn: 35,
+        },
+      ],
+    },
+    {
+      code: 'const foo = <button on={{ click: () => {} }} />;',
+      options: [{ allowTypedFunctionExpressions: false }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 1,
+          endLine: 1,
+          column: 27,
+          endColumn: 34,
+        },
+      ],
+    },
+    {
+      code: 'const foo = <Bar>{() => {}}</Bar>;',
+      options: [{ allowTypedFunctionExpressions: false }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 1,
+          endLine: 1,
+          column: 22,
+          endColumn: 24,
+        },
+      ],
+    },
+    {
+      code: 'const foo = <Bar>{{ on: () => {} }}</Bar>;',
+      options: [{ allowTypedFunctionExpressions: false }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 1,
+          endLine: 1,
+          column: 21,
+          endColumn: 25,
+        },
+      ],
+    },
+    {
+      code: 'const foo = <button {...{ onClick: () => {} }} />;',
+      options: [{ allowTypedFunctionExpressions: false }],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 1,
+          endLine: 1,
+          column: 27,
+          endColumn: 36,
+        },
+      ],
+    },
     {
       code: '() => () => {};',
       options: [{ allowHigherOrderFunctions: true }],