Fix inference with conditionally compiled tails

[DJMcNab]

Fixes #8378

[matklad]

Probably needs a test as well?

[DJMcNab]

Ok, I've added a test

[lnicola]

r? @flodiebold

@DJMcNab can you rebase?

[DJMcNab]

Oof, just confused myself massively by not realising that the main branch is called master instead of my muscle memory main. And then even after typing out this comment, I tried to run git rebase main 😅

Rebased.

[lnicola]

Have you tried git config --global init.defaultBranch master? 😄

[matklad]

Yeah, we use the same defualt branch as rust-lang/rust repo.

[DJMcNab]

Yeah, I did suspect that was the reason - I don't know how well set-up rust-lang/rust would be for non-master default branches, and it's not high priority.

Obviously I would prefer us to use main, primarily for consistency with the other projects I use and muscle memory purposes. Also it's shorter, which is a bonus.

[flodiebold]

bors r+

[bors]

Build succeeded:

• Rust (macos-latest)
• Rust (ubuntu-latest)
• Rust (windows-latest)
• TypeScript (ubuntu-latest)
• TypeScript (windows-latest)