Tests fail to compile on 1.34.0-nightly

[RalfNorthman]

I'm on 1.34.0-nightly and tried to do some trivial things with s! but I couldn't get my code to compile.
I'm using interpolate 0.2.3. My next step was to run cargo test -p interpolate in my project.
This is what I got:

$ cargo test -p interpolate
    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
     Running target/debug/deps/interpolate-c5fc2b5f74fbaa21

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests interpolate

running 1 test
test src/lib.rs -  (line 7) ... FAILED

failures:

---- src/lib.rs -  (line 7) stdout ----
error[E0658]: procedural macros cannot be expanded to expressions (see issue #54727)
 --> src/lib.rs:12:13
  |
8 | let greet = s!("Hello, {name}");
  |             ^^^^^^^^^^^^^^^^^^^
  |
  = help: add #![feature(proc_macro_hygiene)] to the crate attributes to enable

error: expected `[`, found `fmt`
 --> src/lib.rs:12:13
  |
8 | let greet = s!("Hello, {name}");
  |             ^^^^^^^^^^^^^^^^^^^ expected `[`

error[E0658]: procedural macros cannot be expanded to expressions (see issue #54727)
 --> src/lib.rs:13:11
  |
9 | let sos = s!("HELP, {name.to_uppercase()}");
  |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: add #![feature(proc_macro_hygiene)] to the crate attributes to enable

error: expected `[`, found `fmt`
 --> src/lib.rs:13:11
  |
9 | let sos = s!("HELP, {name.to_uppercase()}");
  |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `[`

thread 'src/lib.rs -  (line 7)' panicked at 'couldn't compile the test', src/librustdoc/test.rs:351:13
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.


failures:
    src/lib.rs -  (line 7)

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out

error: test failed, to rerun pass '--doc'
$ rustc --version
rustc 1.34.0-nightly (e1c6d0057 2019-02-22)
$ cargo --version
cargo 1.34.0-nightly (b33ce7fc9 2019-02-19)

[Boscop]

@anowell Any update on this? :)
I'm also running into these errors on the latest nightly..