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Addresses phpstan#3613 (comment)

Author: pmjones

stubs/core.stub

@@ -69,12 +69,15 @@ function str_shuffle(string $string): string {}
 
 /**
  * @param array<mixed> $result
- * @param-out ($string is lowercase-string
- *     	? array<int|string, array<mixed>|lowercase-string>
- *     	: ($string is uppercase-string
- *    		? array<int|string, array<mixed>|uppercase-string>
- *         	: array<int|string, array<mixed>|string>
- *     	)
+ * @param-out ($string is lowercase-string&uppercase-string
+ * 		? array<int|string, array<mixed>|(lowercase-string&uppercase-string)>
+ * 		: ($string is lowercase-string
+ *     		? array<int|string, array<mixed>|lowercase-string>
+ *     		: ($string is uppercase-string
+ *    			? array<int|string, array<mixed>|uppercase-string>
+ *         		: array<int|string, array<mixed>|string>
+ *     		)
+ * 		)
  * 	) $result
  */
 function parse_str(string $string, array &$result): void {}