Fix slow enum cases union with lots of cases

Author: staabm

phpstan-baseline.neon

@@ -1597,6 +1597,11 @@ parameters:
 			count: 4
 			path: src/Type/TypeCombinator.php
 
+		-
+			message: "#^Doing instanceof PHPStan\\\\Type\\\\Enum\\\\EnumCaseObjectType is error\\-prone and deprecated\\. Use Type\\:\\:getEnumCases\\(\\) instead\\.$#"
+			count: 1
+			path: src/Type/TypeCombinator.php
+
 		-
 			message: "#^Doing instanceof PHPStan\\\\Type\\\\FloatType is error\\-prone and deprecated\\. Use Type\\:\\:isFloat\\(\\) instead\\.$#"
 			count: 1

src/Type/TypeCombinator.php

@@ -16,6 +16,7 @@
 use PHPStan\Type\Constant\ConstantFloatType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\Enum\EnumCaseObjectType;
 use PHPStan\Type\Generic\GenericClassStringType;
 use PHPStan\Type\Generic\TemplateArrayType;
 use PHPStan\Type\Generic\TemplateBenevolentUnionType;
@@ -200,8 +201,7 @@ public static function union(Type ...$types): Type
 			if ($types[$i] instanceof StringType && !$types[$i] instanceof ClassStringType) {
 				$hasGenericScalarTypes[ConstantStringType::class] = true;
 			}
-			$enumCases = $types[$i]->getEnumCases();
-			if (count($enumCases) === 1) {
+			if ($types[$i] instanceof EnumCaseObjectType) {
 				$enumCaseTypes[$types[$i]->describe(VerbosityLevel::cache())] = $types[$i];
 
 				unset($types[$i]);

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -1299,6 +1299,16 @@ public function testBug10538(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testBug10772(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1.');
+		}
+
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-10772.php');
+		$this->assertNoErrors($errors);
+	}
+
 	/**
 	 * @param string[]|null $allAnalysedFiles
 	 * @return Error[]