doctest doesn't run under the same profile as the rest of the tests

[rickwebiii]

I have some code that is very optimization-sensitive when it comes to performance. As such, in CI I always run cargo test --release, but noticed my doctests take an order of magnitude or so longer to complete. I've always assumed that rustdoc builds the documentation tests under the same profile settings as the rest of the tests, but this doesn't seem to be the case as I verified in this playground repro.

/// Docs
///
/// ```rust
/// if cfg! (debug_assertions) {
///   panic!("debug");
/// } else {
///   // Ok
/// }
/// ```
pub fn horse() {
    println!("Hello, world!");
}

#[test]
fn cfg() {
    if cfg! (debug_assertions) {
        panic!("debug");
    } else {
        // Ok
    }
}

The unit test fails in debug mode and passes in release mode, while the doctest fails in both.

Meta

Issue occurs in stable, beta, nightly on playground

[ehuss]

Thanks for the report! I believe this is a duplicate of rust-lang/cargo#6570, so closing in favor of that.