interpolate_idents is failing on today's nightly. See, e.g., the error from this Travis build:
error[E0599]: no variant named `Underscore` found for type `syntax::parse::token::Token` in the current scope
--> /home/travis/.cargo/registry/src/github.com-1ecc6299db9ec823/interpolate_idents-0.2.2/src/lib.rs:39:52
|
39 | TokenTree::Token(ref span, Token::Underscore) => {
| ^^^^^^^^^^^^^^^^^ variant not found in `syntax::parse::token::Token`
interpolate_idents
is failing on today's nightly. See, e.g., the error from this Travis build: