Home / Docs / Error Codes / GALA-E0013

GALA-E0013 — Non-defaulted parameter after a defaulted parameter

What it means. A function signature declares a parameter without a default after a parameter that has one. Defaults must be contiguous and at the tail of the parameter list.

Code that triggers it

package main

func create(a int = 5, b int) int = a + b
//                     ^^^^^ no default, but follows a default

func main() {
    Println(create(1, 2))
}

Compiler message

error[GALA-E0013]: parameter "b" in create has no default but follows a parameter with a default
  --> e0013.gala:3:1
  |
3 | func create(a int = 5, b int) int = a + b
  | ^^^^ move parameters with defaults to the end of the parameter li…
  |
  = hint: move parameters with defaults to the end of the parameter list

The caret marks the declaration; the header names the offending parameter.

How to fix it

Reorder so every default sits at the end:

func create(b int, a int = 5) int = a + b

Or give the follower a default too:

func create(a int = 5, b int = 0) int = a + b

Why the rule exists

With mixed defaults, positional calls become ambiguous: does create(7) mean a = 7, b = default or a = default, b = 7? Requiring contiguous trailing defaults keeps positional calls unambiguous, while named-argument calls can still pick any subset.