Add test for non-object string cast reporting dead catch

Ensures that casting a non-object type (int) to string correctly
reports the catch block as dead code, since no __toString() method
is involved and no exception can be thrown.

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

Author: phpstan-bot

tests/PHPStan/Rules/Exceptions/CatchWithUnthrownExceptionRuleTest.php

@@ -736,7 +736,12 @@ public function testBug9146NonStrict(): void
 
 	public function testBug13806(): void
 	{
-		$this->analyse([__DIR__ . '/data/bug-13806.php'], []);
+		$this->analyse([__DIR__ . '/data/bug-13806.php'], [
+			[
+				'Dead catch - Throwable is never thrown in the try block.',
+				27,
+			],
+		]);
 	}
 
 }

tests/PHPStan/Rules/Exceptions/data/bug-13806.php

@@ -20,3 +20,14 @@ public function __toString(): never {
 }
 
 castToString(new MyString());
+
+function castIntToString(int $variable): string {
+	try {
+		$value = (string) $variable;
+	} catch(\Throwable) {
+		var_dump("Error thrown during string-conversion!");
+		$value = '';
+	}
+
+	return $value;
+}