fix

vlib/v/checker/fn.v

@@ -1684,16 +1684,15 @@ fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool) ast.
 					}
 				}
 				out: for n in 0 .. arg_typ_sym.info.types.len {
-					num_arg := n + 1
 					curr_arg := arg_typs[n]
 					multi_param := if func.is_variadic && i >= func.params.len - 1 {
 						func.params.last()
 					} else {
-						func.params[i + n]
+						func.params[n + i]
 					}
 					c.check_expected_call_arg(curr_arg, c.unwrap_generic(multi_param.typ),
 						node.language, call_arg) or {
-						c.error('${err.msg()} in argument ${i + num_arg} to `${fn_name}` from ${c.table.type_to_str(arg_typ)}',
+						c.error('${err.msg()} in argument ${i + n + 1} to `${fn_name}` from ${c.table.type_to_str(arg_typ)}',
 							call_arg.pos)
 						continue out
 					}

vlib/v/checker/tests/multi_return_arg_missing_err.out

@@ -1,20 +1,15 @@
-vlib/v/checker/tests/multi_return_arg_missing_err.vv:9:14: error: unknown function: ret_2
+vlib/v/checker/tests/multi_return_arg_missing_err.vv:9:14: error: expected 2 arguments, but got 3
     7 | 
     8 | fn main() {
-    9 |     expect_2(1, ret_2())
+    9 |     expect_2(1, returning_2())
-      |                 ~~~~~~~
+      |                 ~~~~~~~~~~~~~
-   10 |     expect_2(returning_2(), 1)
-   11 | }
-vlib/v/checker/tests/multi_return_arg_missing_err.vv:9:14: error: `ret_2()` (no value) used as value in argument 2 to `expect_2`
-    7 | 
-    8 | fn main() {
-    9 |     expect_2(1, ret_2())
-      |                 ~~~~~~~
    10 |     expect_2(returning_2(), 1)
    11 | }
+Details: have (int literal, (int, int))
+         want (int, int)
 vlib/v/checker/tests/multi_return_arg_missing_err.vv:10:26: error: expected 2 arguments, but got 3
     8 | fn main() {
-    9 |     expect_2(1, ret_2())
+    9 |     expect_2(1, returning_2())
    10 |     expect_2(returning_2(), 1)
       |                             ^
    11 | }

vlib/v/checker/tests/multi_return_arg_missing_err.vv

@@ -6,6 +6,6 @@ fn returning_2() (int, int) {
 }
 
 fn main() {
-	expect_2(1, ret_2())
+	expect_2(1, returning_2())
 	expect_2(returning_2(), 1)
 }