Specifically:

template<typename T> struct TD;

Instantiate this as ‘TD<decltype(foo)>’ to get the full name of the type.

Rust’s does seem more concise.

Note that you don't get the full name of the type with a bad assignment in Rust, you only get the part of the type that was deduced before type checking failed. A generic type might have undeduced blanks, eg. Vec<_>. A side-effect of type inference.