When creating a bin crate inside a lib crate, Cargo.lock is ignored.

[LaylBongers]

When creating a lib project, cargo will add a .gitignore file for it. When you then create a bin project inside that, it will not add another .gitignore, and the first .gitignore causes the Cargo.lock file in the bin to be ignored.
As a solution for this, perhaps change the default lib .gitignore from:

target
Cargo.lock

To:

/target
/Cargo.lock

And do the same for the bin .gitignore, then just add a .gitignore as usual when a new project is created that's nested inside another project, instead of relying the parenting .gitignore to handle that.

[alexcrichton]

This has been brought up in the past, but the current idea is that the generated gitignore is the "most common" one, but it's always quite easily configurable!

The current common use case is to possibly create component libraries in a repo hierarchy in which case you want to ignore all target directories and Cargo.lock files. This isn't always the case, however, but that's why .gitignore is configurable :)

As a result I'm going to close this, but thanks for the report!