fixed compatibility with PHP 8

Author: dg

src/Forms/Controls/HiddenField.php

@@ -46,7 +46,7 @@ public function setValue($value)
 	{
 		if ($value === null) {
 			$value = '';
-		} elseif (!is_scalar($value) && !method_exists($value, '__toString')) {
+		} elseif (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
 			throw new Nette\InvalidArgumentException(sprintf("Value must be scalar or null, %s given in field '%s'.", gettype($value), $this->name));
 		}
 		if (!$this->persistValue) {

src/Forms/Controls/MultiChoiceControl.php

@@ -59,7 +59,7 @@ public function setValue($values)
 		}
 		$flip = [];
 		foreach ($values as $value) {
-			if (!is_scalar($value) && !method_exists($value, '__toString')) {
+			if (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
 				throw new Nette\InvalidArgumentException(sprintf("Values must be scalar, %s given in field '%s'.", gettype($value), $this->name));
 			}
 			$flip[(string) $value] = true;

src/Forms/Controls/TextBase.php

@@ -38,7 +38,7 @@ public function setValue($value)
 	{
 		if ($value === null) {
 			$value = '';
-		} elseif (!is_scalar($value) && !method_exists($value, '__toString')) {
+		} elseif (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
 			throw new Nette\InvalidArgumentException(sprintf("Value must be scalar or null, %s given in field '%s'.", gettype($value), $this->name));
 		}
 		$this->value = $value;