Fix phpstan/phpstan#13857: Incorrect narrowing of nested array after assignment

src/Analyser/ExprHandler/AssignHandler.php

@@ -980,7 +980,9 @@ private function produceArrayDimFetchAssignValueToWrite(array $dimFetchStack, ar
 				}
 
 			} else {
-				$valueToWrite = $offsetValueType->setOffsetValueType($offsetType, $valueToWrite, $i === 0);
+				$unionValues = $i === 0
+					|| ($offsetType !== null && count($offsetType->getConstantScalarTypes()) === 0);
+				$valueToWrite = $offsetValueType->setOffsetValueType($offsetType, $valueToWrite, $unionValues);
 			}
 
 			if ($arrayDimFetch === null || !$offsetValueType->isList()->yes()) {

src/DependencyInjection/AutowiredAttributeServicesExtension.php

@@ -139,7 +139,7 @@ public function loadConfiguration(): void
 
 	/**
 	 * @param class-string $className
-	 * @param array<lowercase-string, non-empty-list<TargetMethodParameter<AutowiredParameter>>> $constructorParameters
+	 * @param array<lowercase-string, list<TargetMethodParameter<AutowiredParameter>>> $constructorParameters
 	 */
 	private function processConstructorParameters(string $className, ServiceDefinition $definition, array $constructorParameters): void
 	{

tests/PHPStan/Analyser/nsrt/assign-nested-arrays.php

@@ -14,7 +14,7 @@ public function doFoo(int $i)
 		$array[$i]['bar'] = 1;
 		$array[$i]['baz'] = 2;
 
-		assertType('non-empty-array<int, array{bar: 1, baz: 2}>', $array);
+		assertType('non-empty-array<int, array{bar: 1, baz?: 2}>', $array);
 	}
 
 	public function doBar(int $i, int $j)
@@ -27,7 +27,7 @@ public function doBar(int $i, int $j)
 		echo $array[$i][$j]['bar'];
 		echo $array[$i][$j]['baz'];
 
-		assertType('non-empty-array<int, non-empty-array<int, array{bar: 1, baz: 2}>>', $array);
+		assertType('non-empty-array<int, non-empty-array<int, array{bar: 1, baz?: 2}>>', $array);
 	}
 
 }

tests/PHPStan/Analyser/nsrt/bug-10438.php

@@ -25,7 +25,7 @@ public function extract(SimpleXMLElement $data, string $type = 'Meta'): array
 			$meta[$key] = [];
 			assertType('array{}', $meta[$key]);
 			foreach ($tag->{$valueName} as $value) {
-				assertType('list<string>', $meta[$key]);
+				assertType('list<string>|string', $meta[$key]);
 				$meta[$key][] = (string)$value;
 			}
 		}

tests/PHPStan/Analyser/nsrt/bug-13857.php

@@ -0,0 +1,24 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13857;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param array<int, array{state: string}> $array
+ */
+function test(array $array, int $id): void {
+	$array[$id]['state'] = 'foo';
+	// only one element was set to 'foo', not all of them.
+	// correct type would be: non-empty-array<int, array{state: string}>
+	assertType('non-empty-array<int, array{state: string}>', $array);
+}
+
+/**
+ * @param array<string, array{name: string, age: int}> $people
+ */
+function test2(array $people, string $key): void {
+	$people[$key]['name'] = 'John';
+	// age becomes optional because $key might not exist yet, creating array{name: 'John'} without age
+	assertType('non-empty-array<string, array{name: string, age?: int}>', $people);
+}

tests/PHPStan/Analyser/nsrt/pr-4390.php

@@ -13,6 +13,6 @@ function (string $s): void {
 		}
 	}
 
-	assertType('non-empty-array<int<0, 9>, non-empty-array<int<0, 9>, string>>', $locations);
-	assertType('non-empty-array<int<0, 9>, string>', $locations[0]);
+	assertType('non-empty-array<int<0, 9>, list<string>>', $locations);
+	assertType('list<string>', $locations[0]);
 };

tests/PHPStan/Rules/Arrays/data/bug-11679.php

@@ -31,7 +31,7 @@ public function sayHello(int $index): bool
 		assertType('array<int, array{foo?: bool}>', $this->arr);
 		if (!isset($this->arr[$index]['foo'])) {
 			$this->arr[$index]['foo'] = true;
-			assertType('non-empty-array<int, array{foo: true}>', $this->arr);
+			assertType('non-empty-array<int, array{foo?: bool}>', $this->arr);
 		}
 		assertType('array<int, array{foo?: bool}>', $this->arr);
 		return $this->arr[$index]['foo']; // PHPStan does not realize 'foo' is set

tests/PHPStan/Rules/Arrays/data/slevomat-foreach-array-key-exists-bug.php

@@ -18,7 +18,7 @@ public function doFoo(array $percentageIntervals, array $changes): void
 						assertType('non-empty-array<array{itemsCount: mixed, interval: mixed}>', $intervalResults);
 						assertType('array{itemsCount: mixed, interval: mixed}', $intervalResults[$key]);
 						$intervalResults[$key]['itemsCount'] += $itemsCount;
-						assertType('non-empty-array<array{itemsCount: (array|float|int), interval: mixed}>', $intervalResults);
+						assertType('non-empty-array<array{itemsCount: mixed, interval: mixed}>', $intervalResults);
 						assertType('array{itemsCount: (array|float|int), interval: mixed}', $intervalResults[$key]);
 					} else {
 						assertType('array<array{itemsCount: mixed, interval: mixed}>', $intervalResults);

tests/PHPStan/Rules/Methods/data/bug-12927.php

@@ -40,7 +40,7 @@ public function sayFoo2(array $list): void
 	{
 		foreach($list as $k => $v) {
 			$list[$k]['abc'] = 'world';
-			assertType("non-empty-list<non-empty-array<string, string>&hasOffsetValue('abc', 'world')>", $list);
+			assertType("non-empty-list<array<string, string>>", $list);
 			assertType("non-empty-array<string, string>&hasOffsetValue('abc', 'world')", $list[$k]);
 		}
 		assertType("list<non-empty-array<string, string>&hasOffsetValue('abc', 'world')>", $list);