GALA-E0052 — function declared inside a function body

When it fires. A named func is declared inside the body of another function, lambda, if or for block:

func main() {
    func helper(x int) int {
        return x + 1
    }
    Println(helper(2))
}

GALA declares named functions and methods only at the top level of a file. A local function is a lambda bound to a val.

Minimal repro.

package main

func main() {
    func helper(x int) int {
        return x + 1
    }
    Println(helper(2))
}

Error output.

error[GALA-E0052]: function `helper` is declared inside a function body
  --> main.gala:4:5
  |
4 |     func helper(x int) int {
  |     ^^^^^^^^^^^ write it as a lambda bound to a `val`
  |
  = hint: write it as a lambda bound to a `val`; here, `val helper = (x int) int => ...`

Fix. Bind a lambda. A lambda states its result type in the same place a function does — after the parameter list — so the declaration’s signature carries over unchanged, and the hint spells it out from your own code:

package main

func main() {
    val helper = (x int) int => x + 1
    Println(helper(2))
}

A block body works the same way, return included:

val clamp = (x int) int => {
    if x < 0 {
        return 0
    }
    return x
}

A lambda cannot refer to its own val while it is being defined. For a recursive local helper, declare the function type with var first and assign the lambda on the next line:

var fact func(int) int
fact = (n int) => if (n <= 1) 1 else n * fact(n - 1)
Println(fact(5))

Three shapes have no lambda form and move to the top level of the file instead, which the hint says for each:

a generic function, func id[T any](x T) T — a lambda cannot take type parameters;
a function with a default parameter value, func greet(name string = "gala") — a lambda parameter cannot carry a default;
a method, func (b Box) Double() int — a method belongs with its receiver type.

Rationale. The grammar admits a function declaration anywhere a statement can go, but a local named function was never part of the language: the reference documents functions at the top level, and every local helper in the standard library, the examples and the tests is a lambda. Go has no nested named functions either, so the declaration used to be copied verbatim into the enclosing Go body and the generated file did not parse. That surfaced as GALA-E0017, the internal-error code, with a request to file a transpiler bug — for source that simply was not GALA. The declaration is now refused where it is written, with the lambda that replaces it.

Making the declaration legal instead would add a second spelling for something the language already has, and would still need its own answer for every feature a top-level function carries — default parameter values, named arguments, type parameters, receivers — none of which a local binding has.

Scope. Only named declarations inside a body are refused. Top-level functions and methods, lambdas anywhere, and calls to a top-level function from inside a body are unaffected.