Revert "PhpStan fixes (#363)"

This reverts commit 68f9d0981f194931e475e2c93730d8e8785c20e4.

src/Dibi/Result.php

@@ -242,6 +242,9 @@ class Result implements IDataSource
 
 		$data = null;
 		$assoc = preg_split('#(\[\]|->|=|\|)#', $assoc, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+		if (!$assoc) {
+			throw new \InvalidArgumentException("Invalid descriptor '$assoc'.");
+		}
 
 		// check columns
 		foreach ($assoc as $as) {