SqlTranslator: convert BackedEnum to scalar (thanks @milo)

Author: dg

src/Database/SqlPreprocessor.php

@@ -189,6 +189,10 @@ private function formatValue($value, string $mode = null): string
 			} elseif ($value instanceof \DateInterval) {
 				return $this->driver->formatDateInterval($value);
 
+			} elseif ($value instanceof \BackedEnum && is_scalar($value->value)) {
+				$this->remaining[] = $value->value;
+				return '?';
+
 			} elseif ($value instanceof \Stringable) {
 				$this->remaining[] = (string) $value;
 				return '?';

tests/Database/SqlPreprocessor.enum.phpt

@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * @phpVersion 8.1
+ * @dataProvider? databases.ini
+ */
+
+declare(strict_types=1);
+
+use Tester\Assert;
+
+require __DIR__ . '/connect.inc.php'; // create $connection
+
+
+enum EnumInt: int
+{
+	case One = 1;
+}
+
+enum EnumString: string
+{
+	case One = 'one';
+}
+
+enum PureEnum
+{
+	case One;
+}
+
+
+$preprocessor = new Nette\Database\SqlPreprocessor($connection);
+
+[$sql, $params] = $preprocessor->process(['SELECT ?', EnumInt::One]);
+Assert::same('SELECT ?', $sql);
+Assert::same([1], $params);
+
+[$sql, $params] = $preprocessor->process(['SELECT ?', EnumString::One]);
+Assert::same('SELECT ?', $sql);
+Assert::same(['one'], $params);
+
+Assert::exception(function () use ($preprocessor) {
+	$preprocessor->process(['SELECT ?', PureEnum::One]);
+}, Nette\InvalidArgumentException::class, 'Unexpected type of parameter: PureEnum');