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GALA-E0012 — Method redefined

What it means. A method with the same name is declared twice on the same type, across any combination of files in the package.

Code that triggers it

package main

type User struct { Name string }

func (u User) Greet() string = "hello"

func (u User) Greet() string = "hola"   // duplicate

func main() {
    Println(User("x").Greet())
}

Compiler message

error[GALA-E0012]: method "Greet" on type "User" in package "main" redefined (also declared at line 5)
  --> e0012same.gala:7:1
  |
7 | func (u User) Greet() string = "hola"
  | ^^^^ remove the duplicate method or rename it
  |
  = hint: remove the duplicate method or rename it

The check spans the whole package, so splitting the duplicates across files does not hide them. With the first Greet in a.gala and the second in b.gala, the header names the other file and the caret narrows to the method name:

error[GALA-E0012]: method "Greet" on type "User" in package "main" redefined (also declared at a.gala:5)
  --> b.gala:3:15
  |
3 | func (u User) Greet() string = "hola"
  |               ^^^^^ remove the duplicate method or rename it
  |
  = hint: remove the duplicate method or rename it

How to fix it

Delete one definition, or rename the second to reflect what it actually does:

func (u User) GreetFormal() string = "hola"

Why the rule exists

Method resolution uses a single map keyed by method name. A second declaration would silently replace the first, making behavior depend on file-loading order — the hardest kind of bug to reproduce. This also mirrors Go’s own rule, which forbids duplicate methods on the same receiver.