funny usingnamespcae weirdness

usingnamespace.zig

usingnamespace closure: {
  var hashes: []const usize = &[0]usize{};

  break :closure struct {
    pub fn ctStrHash(comptime str: []const u8) usize {
      const hash = yourAlgo(str);
      comptime {
        for (hashes) |existing| {
          if (existing == hash) @compileError("collision");
        }
        hashes = hashes ++ [1]usize{hash};
      }
      return hash;
    }
  };
};