The original D compiler was written in C++ and used bits of the C++ compiler (like its optimizer and code generator), and was eventually converted to 100% D. It still kinda looks like C++.

It's like my early Fortran code looked like Basic, my early C code looked like Fortran, my C++ code looked like C, and my D code looked like C++.

It takes a while to write code idiomatic to the language your using.