The rust plugin ignores the selected rust "channel" when building a project from the IDE

[SvetlinZarev]

Environment

• IntelliJ Rust plugin version:
  0.2.107.2137-192

• Rust toolchain version:
  rustup 1.19.0 (2af131cf9 2019-09-08)
  stable-x86_64-apple-darwin /default/ (1.38.0 (625451e37 2019-09-23)
  beta-x86_64-apple-darwin 1.39
  nightly-x86_64-apple-darwin 1.40

• IDE name and version:
  CLion 2019.2.3
  Build #CL-192.6817.18, built on September 24, 2019
  Licensed to Svetlin Zarev
  Subscription is active until December 3, 2019
  Runtime version: 11.0.4+10-b304.69 x86_64
  VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
  macOS 10.14.6
  Non-Bundled Plugins: org.intellij.plugins.markdown, org.toml.lang, org.rust.lang

• Operating system:
  macOS 10.14.6

Problem description

The "build" button does not respect the selected rust channel and always uses "stable"

Steps to reproduce

1. Create an empty rust project or open an existing one
2. Open "Run/Debug configurations" and select beta/nightly channel
3. Build project

From the console output we can see that the "build" uses the default channel (i.e. stable in my case):

/Users/svetlin/.cargo/bin/cargo build --color=always --all --all-targets

My expectation is to use the selected channel -> i.e. beta/nightly:

/Users/svetlin/.cargo/bin/cargo +beta build --color=always --all --all-targets

For instance the "Run" button works as expected and properly adds "+beta/nightly" depending on the selected channel, but the build button ignores teh selected channel, which results in failing build.

As async/await is in beta, the following piece of code should fail to compile using stable. So select "beta" in the run configuration and click on the "build" button.

Expectation: build passes
Acgual behavior: build fails, because teh wrong rust channel is used

fn main() {
    let future = test();
}

async fn test() -> u32{
    42
}