From 941684de220680840e2d1fdc61d5c835300bca57 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Ma=C5=A1a?= <frantisekmasa1@gmail.com>
Date: Fri, 8 Jun 2018 14:00:06 +0200
Subject: [PATCH] Generalize filtered array with maybe falsey values

---
 ...terFunctionReturnTypeReturnTypeExtension.php | 17 ++++++++++++-----
 .../PHPStan/Analyser/NodeScopeResolverTest.php  |  4 ++++
 tests/PHPStan/Analyser/data/array-functions.php |  7 +++++++
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/Type/Php/ArrayFilterFunctionReturnTypeReturnTypeExtension.php b/src/Type/Php/ArrayFilterFunctionReturnTypeReturnTypeExtension.php
index c4a4fa329a..ec9dbf4665 100644
--- a/src/Type/Php/ArrayFilterFunctionReturnTypeReturnTypeExtension.php
+++ b/src/Type/Php/ArrayFilterFunctionReturnTypeReturnTypeExtension.php
@@ -84,15 +84,22 @@ public function removeFalsey(Type $type): Type
 			$keys = $type->getKeyTypes();
 			$values = $type->getValueTypes();
 
+			$generalize = false;
+
 			foreach ($values as $offset => $value) {
-				if (!$falseyTypes->isSuperTypeOf($value)->yes()) {
-					continue;
-				}
+				$isFalsey = $falseyTypes->isSuperTypeOf($value);
 
-				unset($keys[$offset], $values[$offset]);
+				if ($isFalsey->yes()) {
+					unset($keys[$offset], $values[$offset]);
+				} elseif ($isFalsey->maybe()) {
+					$values[$offset] = TypeCombinator::remove($values[$offset], $falseyTypes);
+					$generalize = true;
+				}
 			}
 
-			return new ConstantArrayType(array_values($keys), array_values($values));
+			$filteredArray = new ConstantArrayType(array_values($keys), array_values($values));
+
+			return $generalize ? $filteredArray->generalize() : $filteredArray;
 		}
 
 		$keyType = $type->getIterableKeyType();
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 37056d0815..9a7f5781e2 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -4144,6 +4144,10 @@ public function dataArrayFunctions(): array
 				'array(\'a\' => 1)',
 				'array_filter($union)',
 			],
+			[
+				'array<int, int|true>',
+				'array_filter($withPossiblyFalsey)',
+			],
 		];
 	}
 
diff --git a/tests/PHPStan/Analyser/data/array-functions.php b/tests/PHPStan/Analyser/data/array-functions.php
index 3dddf23370..63f15ef954 100644
--- a/tests/PHPStan/Analyser/data/array-functions.php
+++ b/tests/PHPStan/Analyser/data/array-functions.php
@@ -56,6 +56,13 @@
 	$union['b'] = false;
 }
 
+/** @var bool $bool */
+$bool = doFoo();
+/** @var int $integer */
+$integer = doFoo();
+
+$withPossiblyFalsey = [$bool, $integer, '', 'a' => 0];
+
 /** @var array<string, int> $generalStringKeys */
 $generalStringKeys = doFoo();