From 4cf40e2af828a6917247e124bf3c5d47138530e4 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <richard@frank.nl>
Date: Thu, 16 Jun 2022 09:59:19 +0200
Subject: [PATCH] Improve intersecting constant array with general array

---
 src/Type/TypeCombinator.php                   | 24 +++++++++++++++++++
 .../Analyser/NodeScopeResolverTest.php        |  1 +
 .../data/constant-array-intersect.php         | 17 +++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/data/constant-array-intersect.php

diff --git a/src/Type/TypeCombinator.php b/src/Type/TypeCombinator.php
index a594f1a8e62..1c2b2af60e0 100644
--- a/src/Type/TypeCombinator.php
+++ b/src/Type/TypeCombinator.php
@@ -6,6 +6,7 @@
 use PHPStan\Type\Accessory\HasOffsetType;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\Constant\ConstantArrayType;
+use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\Constant\ConstantFloatType;
 use PHPStan\Type\Constant\ConstantIntegerType;
@@ -683,6 +684,13 @@ public static function intersect(Type ...$types): Type
 				return 1;
 			}
 
+			if ($a instanceof ConstantArrayType && !$b instanceof ConstantArrayType) {
+				return -1;
+			}
+			if ($b instanceof ConstantArrayType && !$a instanceof ConstantArrayType) {
+				return 1;
+			}
+
 			return 0;
 		});
 
@@ -771,6 +779,22 @@ public static function intersect(Type ...$types): Type
 						continue 2;
 					}
 
+					if ($types[$i] instanceof ConstantArrayType && $types[$j] instanceof ArrayType && !$types[$j] instanceof ConstantArrayType) {
+						$newArray = ConstantArrayTypeBuilder::createEmpty();
+						$valueTypes = $types[$i]->getValueTypes();
+						foreach ($types[$i]->getKeyTypes() as $k => $keyType) {
+							$newArray->setOffsetValueType(
+								self::intersect($keyType, $types[$j]->getIterableKeyType()),
+								self::intersect($valueTypes[$k], $types[$j]->getIterableValueType()),
+								$types[$i]->isOptionalKey($k),
+							);
+						}
+						$types[$i] = $newArray->getArray();
+						array_splice($types, $j--, 1);
+						$typesCount--;
+						continue 2;
+					}
+
 					if (
 						($types[$i] instanceof ArrayType || $types[$i] instanceof IterableType) &&
 						($types[$j] instanceof ArrayType || $types[$j] instanceof IterableType)
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index fdf67bc2a8c..b77b86240d4 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -912,6 +912,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7387.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7353.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7031.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/constant-array-intersect.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/constant-array-intersect.php b/tests/PHPStan/Analyser/data/constant-array-intersect.php
new file mode 100644
index 00000000000..c1633bb14ab
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/constant-array-intersect.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace ConstantArrayIntersect;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param array{key: string|null}&array<string> $array1
+ * @param array<string>&array{key: string|null} $array2
+ */
+function test(
+	array $array1,
+	array $array2,
+): void {
+	assertType('array{key: string}', $array1);
+	assertType('array{key: string}', $array2);
+}