Fixes #12682

Author: CViniciusSDias

ext/standard/string.c

@@ -1035,7 +1035,7 @@ PHP_FUNCTION(implode)
 
 	if (pieces == NULL) {
 		if (arg1_array == NULL) {
-			zend_type_error("%s(): Argument #1 ($array) must be of type array, string given", get_active_function_name());
+			zend_type_error("%s(): Argument #1 ($array) must be of type array, null given", get_active_function_name());
 			RETURN_THROWS();
 		}
 

ext/standard/tests/strings/join_error1.phpt

@@ -0,0 +1,12 @@
+--TEST--
+join() function - error when passing null as the array parameter
+--FILE--
+<?php
+try {
+    join('', null);
+} catch (TypeError $e) {
+    echo $e->getMessage();
+}
+?>
+--EXPECT--
+join(): Argument #2 ($array) must be of type array, null given