Error building proc-macro2 under futures-await

[awestlake87]

I'm getting these errors when I build futures-await now under nightly-2018-01-04-x86_64-unknown-linux-gnu (I've tried older toolchains and I get the same error).

   Compiling proc-macro2 v0.2.3
error[E0599]: no method named `resolved_at` found for type `proc_macro::Span` in the current scope
   --> /home/najen/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.2.3/src/unstable.rs:234:21
    |
234 |         Span(self.0.resolved_at(other.0))
    |                     ^^^^^^^^^^^

error[E0599]: no method named `located_at` found for type `proc_macro::Span` in the current scope
   --> /home/najen/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.2.3/src/unstable.rs:238:21
    |
238 |         Span(self.0.located_at(other.0))
    |                     ^^^^^^^^^^

error[E0599]: no method named `resolved_at` found for type `proc_macro::Span` in the current scope
   --> /home/najen/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.2.3/src/unstable.rs:234:21
    |
234 |         Span(self.0.resolved_at(other.0))
    |                     ^^^^^^^^^^^

error[E0599]: no method named `located_at` found for type `proc_macro::Span` in the current scope
   --> /home/najen/.cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.2.3/src/unstable.rs:238:21
    |
238 |         Span(self.0.located_at(other.0))
    |                     ^^^^^^^^^^

error: aborting due to 2 previous errors

error: Could not compile `proc-macro2`.

I cloned proc-macro2 and it builds fine under the same toolchain, so it seems like it has something to do with futures await.

[alexcrichton]

Thanks for the report! For the nightly feature though you'll need an updated nightly compiler, so rustup update nightly should do it!