cargo +1.29.0  build  '--no-default-features' '--features=rand use-serde base64' # cargo 1.29.0 (524a578d7 2018-08-05)

error[E0658]: access to extern crates through prelude is experimental (see issue #44660)
   --> src/util/amount.rs:938:27
    |
938 |         impl<'de, ValueT> serde::de::Visitor<'de> for Visitor<ValueT>
    |                           ^^^^^

error[E0658]: access to extern crates through prelude is experimental (see issue #44660)
   --> src/util/amount.rs:949:29
    |
949 |             fn visit_str<E: serde::de::Error>(self, v: &str) -> Result<Self::Value, E> {
    |                             ^^^^^

error[E0658]: access to extern crates through prelude is experimental (see issue #44660)
   --> src/util/amount.rs:953:38
    |
953 |             fn visit_borrowed_str<E: serde::de::Error>(self, v: &'de str) -> Result<Self::Value, E> {
    |                                      ^^^^^

error[E0658]: access to extern crates through prelude is experimental (see issue #44660)
   --> src/util/amount.rs:957:32
    |
957 |             fn visit_string<E: serde::de::Error>(self, v: String) -> Result<Self::Value, E> {
    |                                ^^^^^