Do not merge BenevolentUnionType with UnionType

src/Type/TypeCombinator.php

@@ -145,25 +145,12 @@ public static function union(Type ...$types): Type
 			return new NeverType();
 		}
 
-		$benevolentTypes = [];
-		$benevolentUnionObject = null;
 		// transform A | (B | C) to A | B | C
 		for ($i = 0; $i < $typesCount; $i++) {
-			if ($types[$i] instanceof BenevolentUnionType) {
-				if ($types[$i] instanceof TemplateBenevolentUnionType && $benevolentUnionObject === null) {
-					$benevolentUnionObject = $types[$i];
-				}
-				$benevolentTypesCount = 0;
-				$typesInner = $types[$i]->getTypes();
-				foreach ($typesInner as $benevolentInnerType) {
-					$benevolentTypesCount++;
-					$benevolentTypes[$benevolentInnerType->describe(VerbosityLevel::value())] = $benevolentInnerType;
-				}
-				array_splice($types, $i, 1, $typesInner);
-				$typesCount += $benevolentTypesCount - 1;
+			if (!($types[$i] instanceof UnionType)) {
 				continue;
 			}
-			if (!($types[$i] instanceof UnionType)) {
+			if ($types[$i] instanceof BenevolentUnionType) {
 				continue;
 			}
 			if ($types[$i] instanceof TemplateType) {
@@ -347,25 +334,6 @@ public static function union(Type ...$types): Type
 			return $types[0];
 		}
 
-		if ($benevolentTypes !== []) {
-			$tempTypes = $types;
-			foreach ($tempTypes as $i => $type) {
-				if (!isset($benevolentTypes[$type->describe(VerbosityLevel::value())])) {
-					break;
-				}
-
-				unset($tempTypes[$i]);
-			}
-
-			if ($tempTypes === []) {
-				if ($benevolentUnionObject instanceof TemplateBenevolentUnionType) {
-					return $benevolentUnionObject->withTypes($types);
-				}
-
-				return new BenevolentUnionType($types);
-			}
-		}
-
 		return new UnionType($types, true);
 	}
 

src/Type/UnionType.php

@@ -70,6 +70,9 @@ public function __construct(private array $types, private bool $normalized = fal
 			if (!($type instanceof UnionType)) {
 				continue;
 			}
+			if ($type instanceof BenevolentUnionType) {
+				continue;
+			}
 			if ($type instanceof TemplateType) {
 				continue;
 			}

tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php

@@ -4942,11 +4942,11 @@ public function dataArrayFunctions(): array
 				'array_search(new stdClass, $generalStringKeys, true)',
 			],
 			[
-				'int|string|false',
+				'(int|string)|false',
 				'array_search($mixed, $array, true)',
 			],
 			[
-				'int|string|false',
+				'(int|string)|false',
 				'array_search($mixed, $array, false)',
 			],
 			[
@@ -5006,15 +5006,15 @@ public function dataArrayFunctions(): array
 				'array_search(\'id\', doFoo() ? $thisDoesNotExistAndIsMixedInUnion : false, true)',
 			],
 			[
-				'int|string|false',
+				'(int|string)|false',
 				'array_search(1, $generalIntegers, true)',
 			],
 			[
-				'int|string|false',
+				'(int|string)|false',
 				'array_search(1, $generalIntegers, false)',
 			],
 			[
-				'int|string|false',
+				'(int|string)|false',
 				'array_search(1, $generalIntegers)',
 			],
 			[
@@ -8820,11 +8820,11 @@ public function dataPhp73Functions(): array
 				'json_decode($mixed, false, 512, $integer | JSON_THROW_ON_ERROR | JSON_NUMERIC_CHECK)',
 			],
 			[
-				'int|string|null',
+				'(int|string)|null',
 				'array_key_first($mixedArray)',
 			],
 			[
-				'int|string|null',
+				'(int|string)|null',
 				'array_key_last($mixedArray)',
 			],
 			[
@@ -8904,7 +8904,7 @@ public function dataPhp73Functions(): array
 				'$hrtime3',
 			],
 			[
-				'array{int, int}|float|int',
+				'(float|int)|array{int, int}',
 				'$hrtime4',
 			],
 		];

tests/PHPStan/Analyser/nsrt/array-search-php7.php

@@ -12,9 +12,9 @@ class Foo
 	public function mixedAndSubtractedArray($mixed, string $string): void
 	{
 		if (is_array($mixed)) {
-			assertType('int|string|false', array_search('foo', $mixed, true));
-			assertType('int|string|false', array_search('foo', $mixed));
-			assertType('int|string|false', array_search($string, $mixed, true));
+			assertType('(int|string)|false', array_search('foo', $mixed, true));
+			assertType('(int|string)|false', array_search('foo', $mixed));
+			assertType('(int|string)|false', array_search($string, $mixed, true));
 		} else {
 			assertType('mixed~array', $mixed);
 			assertType('null', array_search('foo', $mixed, true));

tests/PHPStan/Analyser/nsrt/array-search-php8.php

@@ -12,9 +12,9 @@ class Foo
 	public function mixedAndSubtractedArray($mixed, string $string): void
 	{
 		if (is_array($mixed)) {
-			assertType('int|string|false', array_search('foo', $mixed, true));
-			assertType('int|string|false', array_search('foo', $mixed));
-			assertType('int|string|false', array_search($string, $mixed, true));
+			assertType('(int|string)|false', array_search('foo', $mixed, true));
+			assertType('(int|string)|false', array_search('foo', $mixed));
+			assertType('(int|string)|false', array_search($string, $mixed, true));
 		} else {
 			assertType('mixed~array', $mixed);
 			assertType('*NEVER*', array_search('foo', $mixed, true));

tests/PHPStan/Analyser/nsrt/array-search.php

@@ -10,9 +10,9 @@ class Foo
 	public function nonEmpty(array $arr, string $string): void
 	{
 		/** @var non-empty-array<string> $arr */
-		assertType('int|string|false', array_search('foo', $arr, true));
-		assertType('int|string|false', array_search('foo', $arr));
-		assertType('int|string|false', array_search($string, $arr, true));
+		assertType('(int|string)|false', array_search('foo', $arr, true));
+		assertType('(int|string)|false', array_search('foo', $arr));
+		assertType('(int|string)|false', array_search($string, $arr, true));
 	}
 
 	public function normalArrays(array $arr, string $string): void

tests/PHPStan/Analyser/nsrt/bug-7279.php

@@ -0,0 +1,87 @@
+<?php declare(strict_types = 1);
+
+namespace Bug7279;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T
+ */
+class Timeline {}
+class Percentage {}
+
+/**
+ * @template K of array-key
+ * @template T
+ *
+ * @param array<K, T> $array
+ * @param (callable(T, K): bool) $fn
+ *
+ * @return ($array is non-empty-array ? T|null : null)
+ */
+function find(array $array, callable $fn): mixed
+{
+	foreach ($array as $key => $value) {
+		if ($fn($value, $key)) {
+			return $value;
+		}
+	}
+
+	return null;
+}
+
+/**
+ * @template K of array-key
+ * @template T
+ *
+ * @param array<K, T> $array
+ * @param (callable(T, K): bool) $fn
+ *
+ * @return ($array is non-empty-array ? K|null : null)
+ */
+function findKey(array $array, callable $fn): string|int|null
+{
+	foreach ($array as $key => $value) {
+		if ($fn($value, $key)) {
+			return $key;
+		}
+	}
+
+	return null;
+}
+
+/**
+ * @param callable(mixed): bool $callback
+ * @param array<never, never> $emptyList
+ * @param array{} $emptyMap
+ * @param array<int, string> $unknownList
+ * @param array{id?: int, name?: string} $unknownMap
+ * @param non-empty-array<int, Timeline<Percentage>> $nonEmptyList
+ * @param array{work: Timeline<Percentage>} $nonEmptyMap
+ */
+function doFoo(callable $callback, array $emptyList, array $emptyMap, array $unknownList, array $unknownMap, array $nonEmptyList, array $nonEmptyMap): void
+{
+	// Everything works great for find()
+
+	assertType('null', find([], $callback));
+	assertType('null', find($emptyList, $callback));
+	assertType('null', find($emptyMap, $callback));
+
+	assertType('string|null', find($unknownList, $callback));
+	assertType('int|string|null', find($unknownMap, $callback));
+
+	assertType('Bug7279\Timeline<Bug7279\Percentage>|null', find($nonEmptyList, $callback));
+	assertType('Bug7279\Timeline<Bug7279\Percentage>|null', find($nonEmptyMap, $callback));
+
+	// But everything goes to hell for findKey() ?!?
+
+	assertType('null', findKey([], $callback));
+	assertType('null', findKey($emptyList, $callback));
+	assertType('null', findKey($emptyMap, $callback));
+
+	assertType('int|null', findKey($unknownList, $callback));
+	assertType("'id'|'name'|null", findKey($unknownMap, $callback));
+
+	assertType('int|null', findKey($nonEmptyList, $callback));
+	assertType("'work'|null", findKey($nonEmptyMap, $callback));
+}

tests/PHPStan/Analyser/nsrt/bug-7291.php

@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php // lint >= 8.0
+
+declare(strict_types=1);
 
 namespace Bug7291;