Revert class-string static call to ErrorType per review

Keep ErrorType for `$class::foo()` on non-generic class-string,
consistent with how `object::foo()` reports an error.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Analyser/ExprHandler/StaticCallHandler.php

@@ -291,28 +291,20 @@ public function resolveType(MutatingScope $scope, Expr $expr): Type
 				return $callType;
 			}
 
-			$calledOnClassString = false;
 			if ($expr->class instanceof Name) {
 				$staticMethodCalledOnType = $this->resolveTypeByNameWithLateStaticBinding($scope, $expr->class, $expr->name);
 			} else {
-				$classType = TypeCombinator::removeNull($scope->getType($expr->class));
-				$calledOnClassString = $classType->isClassString()->yes();
-				$staticMethodCalledOnType = $classType->getObjectTypeOrClassStringObjectType();
+				$staticMethodCalledOnType = TypeCombinator::removeNull($scope->getType($expr->class))->getObjectTypeOrClassStringObjectType();
 			}
 
-			$methodName = $expr->name->toString();
 			$callType = $this->methodCallReturnTypeHelper->methodCallReturnType(
 				$scope,
 				$staticMethodCalledOnType,
-				$methodName,
+				$expr->name->toString(),
 				$expr,
 			);
 			if ($callType === null) {
-				if ($calledOnClassString && $staticMethodCalledOnType->hasMethod($methodName)->maybe()) {
-					$callType = new MixedType();
-				} else {
-					$callType = new ErrorType();
-				}
+				$callType = new ErrorType();
 			}
 
 			if ($expr->class instanceof Expr) {

tests/PHPStan/Analyser/nsrt/bug-9844.php

@@ -12,6 +12,6 @@ class HelloWorld
 	 */
 	public function sayHello(string $class): void
 	{
-		assertType('mixed', $class::foo());
+		assertType('*ERROR*', $class::foo());
 	}
 }