From 4457633ce59336269e513c8b60b68e885afc1789 Mon Sep 17 00:00:00 2001
From: Mathias Arlaud <mathias.arlaud@gmail.com>
Date: Tue, 3 Jun 2025 12:32:17 +0200
Subject: [PATCH] [TypeInfo] Handle `key-of` and `value-of` types

---
 .../TypeResolver/StringTypeResolverTest.php   | 17 +++++++++++++-
 .../TypeResolver/StringTypeResolver.php       | 23 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/src/Symfony/Component/TypeInfo/Tests/TypeResolver/StringTypeResolverTest.php b/src/Symfony/Component/TypeInfo/Tests/TypeResolver/StringTypeResolverTest.php
index 9320987c6baed..1ea0390339004 100644
--- a/src/Symfony/Component/TypeInfo/Tests/TypeResolver/StringTypeResolverTest.php
+++ b/src/Symfony/Component/TypeInfo/Tests/TypeResolver/StringTypeResolverTest.php
@@ -152,6 +152,9 @@ public static function resolveDataProvider(): iterable
         yield [Type::generic(Type::object(\DateTime::class), Type::string(), Type::bool()), \DateTime::class.'<string, bool>'];
         yield [Type::generic(Type::object(\DateTime::class), Type::generic(Type::object(\Stringable::class), Type::bool())), \sprintf('%s<%s<bool>>', \DateTime::class, \Stringable::class)];
         yield [Type::int(), 'int<0, 100>'];
+        yield [Type::string(), \sprintf('value-of<%s>', DummyBackedEnum::class)];
+        yield [Type::int(), 'key-of<list<bool>>'];
+        yield [Type::bool(), 'value-of<list<bool>>'];
 
         // union
         yield [Type::union(Type::int(), Type::string()), 'int|string'];
@@ -207,9 +210,21 @@ public function testCannotResolveParentWithoutTypeContext()
         $this->resolver->resolve('parent');
     }
 
-    public function testCannotUnknownIdentifier()
+    public function testCannotResolveUnknownIdentifier()
     {
         $this->expectException(UnsupportedException::class);
         $this->resolver->resolve('unknown');
     }
+
+    public function testCannotResolveKeyOfInvalidType()
+    {
+        $this->expectException(UnsupportedException::class);
+        $this->resolver->resolve('key-of<int>');
+    }
+
+    public function testCannotResolveValueOfInvalidType()
+    {
+        $this->expectException(UnsupportedException::class);
+        $this->resolver->resolve('value-of<int>');
+    }
 }
diff --git a/src/Symfony/Component/TypeInfo/TypeResolver/StringTypeResolver.php b/src/Symfony/Component/TypeInfo/TypeResolver/StringTypeResolver.php
index a172d388a8722..f219824dee1cf 100644
--- a/src/Symfony/Component/TypeInfo/TypeResolver/StringTypeResolver.php
+++ b/src/Symfony/Component/TypeInfo/TypeResolver/StringTypeResolver.php
@@ -38,6 +38,7 @@
 use Symfony\Component\TypeInfo\Exception\InvalidArgumentException;
 use Symfony\Component\TypeInfo\Exception\UnsupportedException;
 use Symfony\Component\TypeInfo\Type;
+use Symfony\Component\TypeInfo\Type\BackedEnumType;
 use Symfony\Component\TypeInfo\Type\BuiltinType;
 use Symfony\Component\TypeInfo\Type\CollectionType;
 use Symfony\Component\TypeInfo\Type\GenericType;
@@ -182,6 +183,28 @@ private function getTypeFromNode(TypeNode $node, ?TypeContext $typeContext): Typ
         }
 
         if ($node instanceof GenericTypeNode) {
+            if ($node->type instanceof IdentifierTypeNode && 'value-of' === $node->type->name) {
+                $type = $this->getTypeFromNode($node->genericTypes[0], $typeContext);
+                if ($type instanceof BackedEnumType) {
+                    return $type->getBackingType();
+                }
+
+                if ($type instanceof CollectionType) {
+                    return $type->getCollectionValueType();
+                }
+
+                throw new \DomainException(\sprintf('"%s" is not a valid type for "value-of".', $node->genericTypes[0]));
+            }
+
+            if ($node->type instanceof IdentifierTypeNode && 'key-of' === $node->type->name) {
+                $type = $this->getTypeFromNode($node->genericTypes[0], $typeContext);
+                if ($type instanceof CollectionType) {
+                    return $type->getCollectionKeyType();
+                }
+
+                throw new \DomainException(\sprintf('"%s" is not a valid type for "key-of".', $node->genericTypes[0]));
+            }
+
             $type = $this->getTypeFromNode($node->type, $typeContext);
 
             // handle integer ranges as simple integers