Determining where all the copies of my crate are coming from

Let's say I have a crate with features ios, android, and desktop. I frequently compile the crate with each one of the features set individually, and also work in an IDE where I have --all-features active, which lets me see errors in both shared and platform-specific code. Unsurprisingly, this counts as four different variations of the crate, leading to four separate copies of the crate data in target/debug/deps and target/debug/incremental. (It might be nice if more of that could be shared, but ...