One big hurdle for C++ programmers learning Rust that I've seen time and time again in various community support channels is fixing their trust issues with the compiler. They are so used to compiler output being useless or worse than useless, they are unable to take advantage of rustc's stellar diagnostics (which frequently tell you exactly what you need to change to make things work) until they force themselves to actually read and internalise them.

Once they realize that the tooling is actually working _with_ them, not _against_ them, they start to pick things up much quicker.