Fix wrong positives about templates in conditional types

src/Rules/PhpDoc/ConditionalReturnTypeRuleHelper.php

@@ -13,6 +13,7 @@
 use PHPStan\Type\TypeTraverser;
 use PHPStan\Type\VerbosityLevel;
 use function array_key_exists;
+use function count;
 use function sprintf;
 use function substr;
 
@@ -24,8 +25,6 @@ class ConditionalReturnTypeRuleHelper
 	 */
 	public function check(ParametersAcceptor $acceptor): array
 	{
-		$templateTypeMap = $acceptor->getTemplateTypeMap();
-
 		$conditionalTypes = [];
 		$parametersByName = [];
 		foreach ($acceptor->getParameters() as $parameter) {
@@ -55,7 +54,17 @@ public function check(ParametersAcceptor $acceptor): array
 				if ($subjectType instanceof StaticType) {
 					continue;
 				}
-				if (!$subjectType instanceof TemplateType || $templateTypeMap->getType($subjectType->getName()) === null) {
+				$templateTypes = [];
+				TypeTraverser::map($subjectType, static function (Type $type, callable $traverse) use (&$templateTypes): Type {
+					if ($type instanceof TemplateType) {
+						$templateTypes[] = $type;
+						return $type;
+					}
+
+					return $traverse($type);
+				});
+
+				if (count($templateTypes) === 0) {
 					$errors[] = RuleErrorBuilder::message(sprintf('Conditional return type uses subject type %s which is not part of PHPDoc @template tags.', $subjectType->describe(VerbosityLevel::typeOnly())))->build();
 					continue;
 				}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1216,6 +1216,8 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8917.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/ds-copy.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/trait-type-alias.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8609.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/PhpDoc/data/bug-8609-function.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/bug-8609.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Bug8609TypeInference;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T of bool
+ */
+class Foo
+{
+
+	/** @return (T is true ? 'foo' : 'bar') */
+	public function doFoo(): string
+	{
+
+	}
+
+}
+
+class Bar
+{
+
+	/**
+	 * @param Foo<true> $f
+	 * @param Foo<false> $g
+	 * @param Foo<bool> $h
+	 * @param Foo $i
+	 */
+	public function doFoo(Foo $f, Foo $g, Foo $h, Foo $i): void
+	{
+		assertType('\'foo\'', $f->doFoo());
+		assertType('\'bar\'', $g->doFoo());
+		assertType('\'bar\'|\'foo\'', $h->doFoo());
+		assertType('\'bar\'|\'foo\'', $i->doFoo());
+	}
+
+}

tests/PHPStan/Rules/PhpDoc/FunctionConditionalReturnTypeRuleTest.php

@@ -63,4 +63,9 @@ public function testRule(): void
 		]);
 	}
 
+	public function testBug8609(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-8609-function.php'], []);
+	}
+
 }

tests/PHPStan/Rules/PhpDoc/MethodConditionalReturnTypeRuleTest.php

@@ -23,10 +23,6 @@ public function testRule(): void
 				'Conditional return type uses subject type stdClass which is not part of PHPDoc @template tags.',
 				48,
 			],
-			[
-				'Conditional return type uses subject type TAboveClass which is not part of PHPDoc @template tags.',
-				57,
-			],
 			[
 				'Conditional return type references unknown parameter $j.',
 				65,
@@ -80,4 +76,9 @@ public function testBug8284(): void
 		]);
 	}
 
+	public function testBug8609(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-8609.php'], []);
+	}
+
 }

tests/PHPStan/Rules/PhpDoc/data/bug-8609-function.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace Bug8609Function;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T of list<string>|list<list<string>>
+ * @param T $bar
+ *
+ * @return (T[0] is string ? array{T} : T)
+ */
+function foo(array $bar) : array{ return is_string($bar[0]) ? [$bar] : $bar; }
+
+function(): void {
+	assertType('array{array{string, string}}', foo(['foo', 'bar']));
+	assertType('array{array{string, string}, array{string, string}}', foo([['foo','bar'],['xyz','asd']]));
+};

tests/PHPStan/Rules/PhpDoc/data/bug-8609.php

@@ -0,0 +1,34 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\PhpDoc\data;
+
+/**
+ * @template T of int
+ */
+class A {
+	/** @var T */
+    private $value;
+
+    /** @param T $value */
+	public function __construct($value) {
+        $this->value = $value;
+	}
+
+	/**
+	 * @template C of int
+	 *
+	 * @param C $coefficient
+	 *
+	 * @return (
+	 *  T is positive-int
+	 *      ? (C is positive-int ? positive-int : negative-int)
+	 *      : T is negative-int
+	 *          ? (C is positive-int ? negative-int : positive-int)
+	 *          : (T is 0 ? 0 : int)
+	 *      )
+	 * )
+	 */
+	public function multiply(int $coefficient): int {
+		return $this->value * $coefficient;
+	}
+}