From 47b9de0e8474e22a24f5f8fdbefe90c77342e7f8 Mon Sep 17 00:00:00 2001
From: waynzh <waynzh19@gmail.com>
Date: Mon, 3 Mar 2025 20:27:00 +0800
Subject: [PATCH] feat: handle generic parameter types

---
 lib/utils/ts-utils/ts-types.js                | 12 ++++++++
 tests/lib/rules/require-valid-default-prop.js | 30 +++++++++++++++++--
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/lib/utils/ts-utils/ts-types.js b/lib/utils/ts-utils/ts-types.js
index 2fe354c2c..7280c8762 100644
--- a/lib/utils/ts-utils/ts-types.js
+++ b/lib/utils/ts-utils/ts-types.js
@@ -202,6 +202,18 @@ function inferRuntimeTypeInternal(type, services) {
   const { checker } = services
   /** @type {Set<string>} */
   const types = new Set()
+
+  // handle generic parameter types
+  if (type.isTypeParameter()) {
+    const constraint = type.getConstraint()
+    if (constraint) {
+      for (const t of inferRuntimeTypeInternal(constraint, services)) {
+        types.add(t)
+      }
+    }
+    return [...types]
+  }
+
   for (const targetType of iterateTypes(checker.getNonNullableType(type))) {
     if (
       isAny(targetType) ||
diff --git a/tests/lib/rules/require-valid-default-prop.js b/tests/lib/rules/require-valid-default-prop.js
index a724d36f7..103b6b7d3 100644
--- a/tests/lib/rules/require-valid-default-prop.js
+++ b/tests/lib/rules/require-valid-default-prop.js
@@ -222,8 +222,7 @@ ruleTester.run('require-valid-default-prop', rule, {
       `,
       languageOptions: {
         parser: require('@typescript-eslint/parser'),
-        ecmaVersion: 6,
-        sourceType: 'module'
+        ...languageOptions
       }
     },
     {
@@ -332,6 +331,17 @@ ruleTester.run('require-valid-default-prop', rule, {
       languageOptions: {
         parser: require('vue-eslint-parser')
       }
+    },
+    {
+      // https://github.com/vuejs/eslint-plugin-vue/issues/2692
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      type MaybeString<T extends number> = T | \`\${T}\`
+      const { foo = 1 } = defineProps<{ foo: MaybeString<1, 2>}>()
+      </script>
+      `,
+      ...getTypeScriptFixtureTestOptions()
     }
   ],
 
@@ -1201,6 +1211,22 @@ ruleTester.run('require-valid-default-prop', rule, {
           line: 3
         }
       ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      type MaybeString<T extends string | number> = \`\${T}\`
+      const { foo = 1 } = defineProps<{ foo: MaybeString<1, 2>}>()
+      </script>
+      `,
+      errors: [
+        {
+          message: "Type of the default value for 'foo' prop must be a string.",
+          line: 4
+        }
+      ],
+      ...getTypeScriptFixtureTestOptions()
     }
   ]
 })