Helper PHPDoc type: template-type (calling Type::getTemplateType() method)

Author: ondrejmirtes

Diff for: src/PhpDoc/TypeNodeResolver.php

@@ -63,6 +63,7 @@
 use PHPStan\Type\FloatType;
 use PHPStan\Type\Generic\GenericClassStringType;
 use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\Helper\GetTemplateTypeType;
 use PHPStan\Type\IntegerRangeType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\IntersectionType;
@@ -670,6 +671,19 @@ private function resolveGenericTypeNode(GenericTypeNode $typeNode, NameScope $na
 			if (count($genericTypes) === 1) {
 				return TypeUtils::toBenevolentUnion($genericTypes[0]);
 			}
+			return new ErrorType();
+		} elseif ($mainTypeName === 'template-type') {
+			if (count($genericTypes) === 3) {
+				$result = [];
+				foreach ($genericTypes[1]->getObjectClassNames() as $ancestorClassName) {
+					foreach ($genericTypes[2]->getConstantStrings() as $templateTypeName) {
+						$result[] = new GetTemplateTypeType($genericTypes[0], $ancestorClassName, $templateTypeName->getValue());
+					}
+				}
+
+				return TypeCombinator::union(...$result);
+			}
+
 			return new ErrorType();
 		}
 

Diff for: src/Type/Helper/GetTemplateTypeType.php

@@ -0,0 +1,83 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Helper;
+
+use PHPStan\Type\CompoundType;
+use PHPStan\Type\Generic\TemplateTypeVariance;
+use PHPStan\Type\LateResolvableType;
+use PHPStan\Type\Traits\LateResolvableTypeTrait;
+use PHPStan\Type\Traits\NonGeneralizableTypeTrait;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeUtils;
+use PHPStan\Type\VerbosityLevel;
+use function sprintf;
+
+/** @api */
+final class GetTemplateTypeType implements CompoundType, LateResolvableType
+{
+
+	use LateResolvableTypeTrait;
+	use NonGeneralizableTypeTrait;
+
+	public function __construct(private Type $type, private string $ancestorClassName, private string $templateTypeName)
+	{
+	}
+
+	public function getReferencedClasses(): array
+	{
+		return $this->type->getReferencedClasses();
+	}
+
+	public function getReferencedTemplateTypes(TemplateTypeVariance $positionVariance): array
+	{
+		return $this->type->getReferencedTemplateTypes($positionVariance);
+	}
+
+	public function equals(Type $type): bool
+	{
+		return $type instanceof self
+			&& $this->type->equals($type->type);
+	}
+
+	public function describe(VerbosityLevel $level): string
+	{
+		return sprintf('template-type<%s, %s, %s>', $this->type->describe($level), $this->ancestorClassName, $this->templateTypeName);
+	}
+
+	public function isResolvable(): bool
+	{
+		return !TypeUtils::containsTemplateType($this->type);
+	}
+
+	protected function getResult(): Type
+	{
+		return $this->type->getTemplateType($this->ancestorClassName, $this->templateTypeName);
+	}
+
+	/**
+	 * @param callable(Type): Type $cb
+	 */
+	public function traverse(callable $cb): Type
+	{
+		$type = $cb($this->type);
+
+		if ($this->type === $type) {
+			return $this;
+		}
+
+		return new self($type, $this->ancestorClassName, $this->templateTypeName);
+	}
+
+	/**
+	 * @param mixed[] $properties
+	 */
+	public static function __set_state(array $properties): Type
+	{
+		return new self(
+			$properties['type'],
+			$properties['ancestorClassName'],
+			$properties['templateTypeName'],
+		);
+	}
+
+}

Diff for: tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -1176,6 +1176,12 @@ public function testBug5091(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testDiscussion9053(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/discussion-9053.php');
+		$this->assertNoErrors($errors);
+	}
+
 	/**
 	 * @param string[]|null $allAnalysedFiles
 	 * @return Error[]

Diff for: tests/PHPStan/Analyser/data/discussion-9053.php

@@ -0,0 +1,110 @@
+<?php
+
+namespace Discussion9053;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template-covariant TChild of ChildInterface
+ */
+interface ModelInterface {
+	/**
+	 * @return TChild[]
+	 */
+	public function getChildren(): array;
+}
+
+/**
+ * @implements ModelInterface<Child>
+ */
+class Model implements ModelInterface
+{
+	/**
+	 * @var Child[]
+	 */
+	public array $children;
+
+	public function getChildren(): array
+	{
+		return $this->children;
+	}
+}
+
+/**
+ * @template-covariant T of ModelInterface
+ */
+interface ChildInterface {
+	/**
+	 * @return T
+	 */
+	public function getModel(): ModelInterface;
+}
+
+
+/**
+ * @implements ChildInterface<Model>
+ */
+class Child implements ChildInterface
+{
+	public function __construct(private Model $model)
+	{
+	}
+
+	public function getModel(): Model
+	{
+		return $this->model;
+	}
+}
+
+/**
+ * @template-covariant T of ModelInterface
+ */
+class Helper
+{
+	/**
+	 * @param T $model
+	 */
+	public function __construct(private ModelInterface $model)
+	{}
+
+	/**
+	 * @return template-type<T, ModelInterface, 'TChild'>
+	 */
+	public function getFirstChildren(): ChildInterface
+	{
+		$firstChildren = $this->model->getChildren()[0] ?? null;
+
+		if (!$firstChildren) {
+			throw new \RuntimeException('No first child found.');
+		}
+
+		return $firstChildren;
+	}
+}
+
+class Other {
+	/**
+	 * @template TChild of ChildInterface
+	 * @template TModel of ModelInterface<TChild>
+	 * @param Helper<TModel> $helper
+	 * @return TChild
+	 */
+	public function getFirstChildren(Helper $helper): ChildInterface {
+		$child = $helper->getFirstChildren();
+		assertType('TChild of Discussion9053\ChildInterface (method Discussion9053\Other::getFirstChildren(), argument)', $child);
+
+		return $child;
+	}
+}
+
+function (): void {
+	$model = new Model();
+	$helper = new Helper($model);
+	assertType('Discussion9053\Helper<Discussion9053\Model>', $helper);
+	$child = $helper->getFirstChildren();
+	assertType('Discussion9053\Child', $child);
+
+	$other = new Other();
+	$child2 = $other->getFirstChildren($helper);
+	assertType('Discussion9053\Child', $child2);
+};