Specify dependencies in the workspace Cargo.toml

[emschwartz]

Currently, it is a pain to ensure that you only have one version of a dependency in a workspace with many crates. I work on a project with 16 crates in a workspace and regularly discover that we are depending on slightly different versions of the same dependency in different crates.

It would be nice to be able to specify dependencies that are used in different sub-crates in the workspace Cargo.toml. These could either automatically override the crates' Cargo.tomls like the [patch] section, or the individual crates could opt in to using the workspace-wide version by specifying version = "workspace".

Apologies if this has been requested before.

Also, thanks for all your work on cargo, it's excellent!

[ehuss]

Does #3931 look like what you're asking for?

[emschwartz]

Yup, thank you!