From 70dd2fca27e90ff70580b0e46b18dadad1f9a5dd Mon Sep 17 00:00:00 2001
From: Richard van Velzen <richard@frank.nl>
Date: Wed, 1 Jun 2022 07:48:04 +0200
Subject: [PATCH] Improve unresolve template type checks for complex
 conditional types

---
 src/Rules/FunctionCallParametersCheck.php     |  2 +-
 .../Analyser/NodeScopeResolverTest.php        |  1 +
 .../Rules/Methods/CallMethodsRuleTest.php     | 10 ++++++
 .../data/conditional-complex-templates.php    | 33 +++++++++++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 tests/PHPStan/Rules/Methods/data/conditional-complex-templates.php

diff --git a/src/Rules/FunctionCallParametersCheck.php b/src/Rules/FunctionCallParametersCheck.php
index bf1c545398..37be0e0d9a 100644
--- a/src/Rules/FunctionCallParametersCheck.php
+++ b/src/Rules/FunctionCallParametersCheck.php
@@ -355,7 +355,7 @@ public function check(
 				TypeTraverser::map(
 					$parametersAcceptor->getReturnTypeWithUnresolvableTemplateTypes(),
 					static function (Type $type, callable $traverse) use (&$returnTemplateTypes): Type {
-						if ($type instanceof ConditionalType) {
+						while ($type instanceof ConditionalType && $type->isResolvable()) {
 							$type = $type->resolve();
 						}
 
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index d13712b926..b7f7cc52bc 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -902,6 +902,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7341.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/non-empty-string-strstr-specifying.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/non-empty-string-strrchr-specifying.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Methods/data/conditional-complex-templates.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
index 177f403a62..8ba25a23a7 100644
--- a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
+++ b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
@@ -2469,4 +2469,14 @@ public function testUnresolvableParameter(): void
 		]);
 	}
 
+
+	public function testConditionalComplexTemplates(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->checkExplicitMixed = false;
+		$this->analyse([__DIR__ . '/data/conditional-complex-templates.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Methods/data/conditional-complex-templates.php b/tests/PHPStan/Rules/Methods/data/conditional-complex-templates.php
new file mode 100644
index 0000000000..1593317e68
--- /dev/null
+++ b/tests/PHPStan/Rules/Methods/data/conditional-complex-templates.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace ConditionalComplexTemplates;
+
+use function PHPStan\Testing\assertType;
+
+/** @template T */
+interface PromiseInterface
+{
+    /**
+     * @template TFulfilled of mixed
+	 * @template TRejected of mixed
+     * @param (callable(T): TFulfilled)|null $onFulfilled
+     * @param (callable(mixed): TRejected)|null $onRejected
+     * @return PromiseInterface<(
+	 *   $onFulfilled is not null
+	 *     ? ($onRejected is not null ? TFulfilled|TRejected : TFulfilled)
+	 *     : ($onRejected is not null ? TRejected : T)
+	 * )>
+     */
+    public function then(callable $onFulfilled = null, callable $onRejected = null);
+}
+
+/**
+ * @param PromiseInterface<true> $promise
+ */
+function test(PromiseInterface $promise): void
+{
+	$passThroughBoolFn = static fn (bool $bool): bool => $bool;
+
+	assertType('ConditionalComplexTemplates\PromiseInterface<bool>', $promise->then($passThroughBoolFn));
+	assertType('ConditionalComplexTemplates\PromiseInterface<bool>', $promise->then()->then($passThroughBoolFn));
+}