From c7e3eedf891e81011e6435687c18b5911dc4bea5 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <richard@frank.nl>
Date: Mon, 28 Mar 2022 16:30:25 +0200
Subject: [PATCH] Support conditional return types by union-ing their branches

First baby step for phpstan/phpstan#3853
---
 src/PhpDoc/TypeNodeResolver.php               | 11 ++++
 .../Analyser/NodeScopeResolverTest.php        |  1 +
 tests/PHPStan/Analyser/data/bug-3853.php      | 53 +++++++++++++++++++
 3 files changed, 65 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/data/bug-3853.php

diff --git a/src/PhpDoc/TypeNodeResolver.php b/src/PhpDoc/TypeNodeResolver.php
index 3c832876b5..9c17658505 100644
--- a/src/PhpDoc/TypeNodeResolver.php
+++ b/src/PhpDoc/TypeNodeResolver.php
@@ -20,6 +20,8 @@
 use PHPStan\PhpDocParser\Ast\Type\ArrayTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\CallableTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\CallableTypeParameterNode;
+use PHPStan\PhpDocParser\Ast\Type\ConditionalTypeForParameterNode;
+use PHPStan\PhpDocParser\Ast\Type\ConditionalTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\ConstTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\GenericTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
@@ -121,6 +123,9 @@ public function resolve(TypeNode $typeNode, NameScope $nameScope): Type
 		} elseif ($typeNode instanceof IntersectionTypeNode) {
 			return $this->resolveIntersectionTypeNode($typeNode, $nameScope);
 
+		} elseif ($typeNode instanceof ConditionalTypeNode || $typeNode instanceof ConditionalTypeForParameterNode) {
+			return $this->resolveConditionalTypeNode($typeNode, $nameScope);
+
 		} elseif ($typeNode instanceof ArrayTypeNode) {
 			return $this->resolveArrayTypeNode($typeNode, $nameScope);
 
@@ -438,6 +443,12 @@ private function resolveIntersectionTypeNode(IntersectionTypeNode $typeNode, Nam
 		return TypeCombinator::intersect(...$types);
 	}
 
+	private function resolveConditionalTypeNode(ConditionalTypeNode|ConditionalTypeForParameterNode $typeNode, NameScope $nameScope): Type
+	{
+		$types = $this->resolveMultiple([$typeNode->if, $typeNode->else], $nameScope);
+		return TypeCombinator::union(...$types);
+	}
+
 	private function resolveArrayTypeNode(ArrayTypeNode $typeNode, NameScope $nameScope): Type
 	{
 		$itemType = $this->resolve($typeNode->type, $nameScope);
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 57b414e5cf..2e5d0e4aed 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -830,6 +830,7 @@ public function dataFileAsserts(): iterable
 		}
 
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6917.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3853.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/bug-3853.php b/tests/PHPStan/Analyser/data/bug-3853.php
new file mode 100644
index 0000000000..54ac3a108f
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/bug-3853.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Bug3853;
+
+use function PHPStan\Testing\assertType;
+
+abstract class Test
+{
+	/**
+	 * @template TKey as array-key
+	 * @template TArray as array<TKey, mixed>
+	 *
+	 * @param TArray $array
+	 *
+	 * @return (TArray is non-empty-array ? non-empty-list<TKey> : list<TKey>)
+	 */
+	abstract public function arrayKeys(array $array);
+
+	/**
+	 * @param array $array
+	 * @param non-empty-array $nonEmptyArray
+	 *
+	 * @param array<int, int> $intArray
+	 * @param non-empty-array<int, int> $nonEmptyIntArray
+	 */
+	public function testArrayKeys(array $array, array $nonEmptyArray, array $intArray, array $nonEmptyIntArray): void
+	{
+		assertType('array<int, (int|string)>', $this->arrayKeys($array));
+		assertType('array<int, int>', $this->arrayKeys($intArray));
+
+		// TODO resolve correctly
+		//assertType('non-empty-array<int, (int|string)>', $this->arrayKeys($nonEmptyArray));
+		//assertType('non-empty-array<int, int>', $this->arrayKeys($nonEmptyIntArray));
+
+		assertType('array<int, (int|string)>', $this->arrayKeys($nonEmptyArray));
+		assertType('array<int, int>', $this->arrayKeys($nonEmptyIntArray));
+	}
+
+	/**
+	 * @return ($as_float is true ? float : string)
+	 */
+	abstract public function microtime(bool $as_float = false);
+
+	public function testMicrotime(): void
+	{
+		// TODO resolve correctly
+		//assertType('float', $this->microtime(true));
+		//assertType('string', $this->microtime(false));
+
+		assertType('float|string', $this->microtime(true));
+		assertType('float|string', $this->microtime(false));
+	}
+}