D and Rust are on the opposite sides at dealing with memory safety. Rust ensures safety by constantly making you think about memory with its highly sophisticated compile-time checks. D, on the other hand, offers you to either employ a GC and forget about (almost) all memory-safety concerns or a block scoped opt-out with cowboy-style manual memory management.

D retains object-oriented programming but also allows functional programming, while Rust seems to be specifically designed for functional programming and does not allow OOP in the conventional sense.

I've been working with D for a couple of months now and I noticed that it's almost a no-brainer to port C/C++ code to D because it mostly builds on the same semantics. With Rust, porting a piece of code may often require rethinking the whole thing from scratch.