diff --git a/compiler/fn.v b/compiler/fn.v
index a7df439f76..7e761640f2 100644
--- a/compiler/fn.v
+++ b/compiler/fn.v
@@ -503,7 +503,7 @@ fn (p mut Parser) async_fn_call(f Fn, method_ph int, receiver_var, receiver_type
 }
 
 fn (p mut Parser) fn_call(f Fn, method_ph int, receiver_var, receiver_type string) {
-	if !f.is_public && !f.is_c && !p.pref.is_test && f.pkg != p.pkg  { 
+	if !f.is_public &&  !f.is_c && !p.pref.is_test && !f.is_interface && f.pkg != p.pkg  { 
 		p.error('function `$f.name` is private')
 	}
 	p.calling_c = f.is_c
diff --git a/vlib/builtin/array.v b/vlib/builtin/array.v
index cec68385e6..0b9e1e999d 100644
--- a/vlib/builtin/array.v
+++ b/vlib/builtin/array.v
@@ -172,6 +172,7 @@ fn (arr mut array) _push(val voidptr) {
 }
 
 // `val` is array.data 
+// TODO make private, right now it's used by strings.Builder 
 pub fn (arr mut array) _push_many(val voidptr, size int) {
 	if arr.len >= arr.cap - size {
 		cap := (arr.len + size) * 2