Rust doesn't even have a formal specification at this time. Technically speaking, everything in Rust is undefined behaviour. That's a hard sell for, e.g., people writing safety-critical systems.
Another problem recently was that compiling Rust required downloading a binary blob from Mozilla. That's a no-go for many projects.
Another problem recently was that compiling Rust required downloading a binary blob from Mozilla. That's a no-go for many projects.