Fix BenevolentUnionType with generics producing false positive errors

- Fixed ArrayType constructor converting StrictMixedType key to regular UnionType instead of BenevolentUnionType, which caused loss of benevolent semantics during RuleLevelHelper type transformation
- Added BenevolentUnionType handling in TemplateTypeTrait::inferTemplateTypes() to filter matching types from a benevolent union when resolving template bounds
- New regression test in tests/PHPStan/Rules/Methods/data/bug-9732.php

Closes phpstan/phpstan#9732

Author: github-actions[bot]

src/Type/ArrayType.php

@@ -54,7 +54,7 @@ public function __construct(Type $keyType, private Type $itemType)
 			$keyType = new MixedType();
 		}
 		if ($keyType instanceof StrictMixedType && !$keyType instanceof TemplateStrictMixedType) {
-			$keyType = new UnionType([new StringType(), new IntegerType()]);
+			$keyType = new BenevolentUnionType([new IntegerType(), new StringType()]);
 		}
 
 		$this->keyType = $keyType;

src/Type/Generic/TemplateTypeTrait.php

@@ -6,6 +6,7 @@
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\BenevolentUnionType;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IsSuperTypeOfResult;
@@ -18,6 +19,7 @@
 use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
+use function count;
 use function sprintf;
 
 /**
@@ -287,6 +289,23 @@ public function inferTemplateTypes(Type $receivedType): TemplateTypeMap
 			]))->union($map);
 		}
 
+		if ($receivedType instanceof BenevolentUnionType) {
+			$matchingTypes = [];
+			foreach ($receivedType->getTypes() as $innerType) {
+				if (!$resolvedBound->isSuperTypeOf($innerType)->yes()) {
+					continue;
+				}
+
+				$matchingTypes[] = $innerType;
+			}
+			if (count($matchingTypes) > 0) {
+				$filteredType = TypeCombinator::union(...$matchingTypes);
+				return (new TemplateTypeMap([
+					$this->name => $filteredType,
+				]))->union($map);
+			}
+		}
+
 		return $map;
 	}
 

tests/PHPStan/Rules/Methods/CallStaticMethodsRuleTest.php

@@ -931,6 +931,15 @@ public function testBug13556(): void
 		$this->analyse([__DIR__ . '/data/bug-13556.php'], []);
 	}
 
+	public function testBug9732(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkExplicitMixed = true;
+		$this->checkImplicitMixed = true;
+
+		$this->analyse([__DIR__ . '/data/bug-9732.php'], []);
+	}
+
 	#[RequiresPhp('>= 8.5')]
 	public function testPipeOperator(): void
 	{

tests/PHPStan/Rules/Methods/data/bug-9732.php

@@ -0,0 +1,23 @@
+<?php declare(strict_types = 1);
+
+namespace Bug9732;
+
+class HelloWorld
+{
+	/**
+	 * @phpstan-template TKeyType of string
+	 * @phpstan-template TValueType
+	 * @phpstan-param array<TKeyType, TValueType> $array
+	 * @phpstan-return \Generator<TKeyType, TValueType, void, void>
+	 */
+	public static function stringifyKeys(array $array) : \Generator{
+		foreach($array as $key => $value){
+			yield (string) $key => $value;
+		}
+	}
+
+	public function sayHello(): void
+	{
+		self::stringifyKeys($GLOBALS);
+	}
+}