When I try to build project that depends on ron@0.7.0 for target wasm32-unknow-emscripten, I have lot of messages like this:

  --> /home/caiiiycuk/.cargo/registry/src/github.com-1ecc6299db9ec823/ron-0.7.0/src/de/id.rs:74:5
   |
74 | /     fn deserialize_i128<V>(self, _: V) -> Result<V::Value>
75 | |     where
76 | |         V: Visitor<'b>,
77 | |     {
78 | |         unimplemented!("IdDeserializer may only be used for identifiers")
79 | |     }
   | |_____^ not a member of trait `de::Deserializer`

I believe it's because emscripten target does not have i128/u182 types. Serde in that case does not have deserialize_i128/u128. As workaround I use version 0.5.1, it does not contains i128/u128 and works fine. However I would like to update to latest version if possible.