Create bug-14084.php

Author: staabm

tests/PHPStan/Analyser/nsrt/bug-14084.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bug14084;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param array<string, list<string>> $convert
+ */
+function example(array $convert): void
+{
+	foreach ($convert as &$inner) {
+		foreach ($inner as &$val) {
+			$val = strtoupper($val); // https://github.com/phpstan/phpstan/issues/14083
+		}
+	}
+	assertType('array<string, list<string>>', $convert);
+}
+
+/**
+ * @param array<string, list<string>> $convert
+ */
+function example2(array $convert): void
+{
+	foreach ($convert as &$inner) {
+		foreach ($inner as $key => $val) {
+			$inner[$key] = strtoupper($val);
+		}
+	}
+	assertType('array<string, list<string>>', $convert);
+}
+
+/**
+ * @param array<string, list<string>> $convert
+ */
+function example3(array &$convert): void
+{
+	foreach ($convert as $outerKey => $inner) {
+		foreach ($inner as $key => $val) {
+			$convert[$outerKey][$key] = strtoupper($val);
+		}
+	}
+	assertType('array<string, list<string>>', $convert);
+}