I would like to suggest that struct methods could be defined outside of the struct and even in different source files.

For example, assume we have a Vec3 struct, defined like this:

const Vec3 = struct {
   x: f32,
   y: f32,
   z: f32,

   pub fn init(x: f32, y: f32, z: f32) Vec3 {
     return Vec3 {
        .x = x,
        .y = y,
        .z = z,
     };
  }

  pub fn dot(self: *const Vec3, other: *const Vec3) f32 {
    return self.x * other.x + self.y * other.y + self.z * other.z;
  }
};

The proposal is that one could define extensions in other files like this:

pub fn Vec3.cross(self: *const Vec3, other: *const Vec3) f32 { ... }

One would obviously need to discuss how (if) this should be supported for generic structs.

This is not UFCS ( discussed in #148 ), but much more narrow change that might be a better fit for Zig.