Non working solution to the man boy problem in zig

manBoyTestFails.zig

const std = @import("std");

const Func = *const fn () i32;

fn x (comptime n: i32) Func {
  return struct {
    fn lambda() i32 { return n; }
  }.lambda;
}

inline fn a (
  comptime k: i32,
  comptime x1: Func,
  comptime x2: Func,
  comptime x3: Func,
  comptime x4: Func,
  comptime x5: Func
) i32 {
  const b = struct {
    fn lambda() i32 {
      return a(k - 1, &lambda, x1, x2, x3, x4);
    }
  }.lambda;
  if (k > 0) { return b(); }
  else { return x4() + x5(); }
}

pub fn main () !void {
  std.debug.print("{}", .{a(0, x(1), x(-1), x(-1), x(1), x(0))});
}