StrCaseFunctionsReturnTypeExtension - do not throw ShouldNotHappenException, it might happen if mbstring is not enabled and the polyfill is not implemented

Author: ondrejmirtes

src/Type/Php/StrCaseFunctionsReturnTypeExtension.php

@@ -6,7 +6,6 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Reflection\ParametersAcceptorSelector;
-use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
 use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
 use PHPStan\Type\Accessory\AccessoryNumericStringType;
@@ -61,7 +60,7 @@ public function getTypeFromFunctionCall(
 
 		$argType = $scope->getType($args[0]->value);
 		if (!is_callable($fnName)) {
-			throw new ShouldNotHappenException();
+			return ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
 		}
 
 		$modes = [];