I've often longed for first class constructors in Go and Rust. It was more of a problem for me with Go because you can omit a struct field when building a value, something you can't do in Rust unless it has an explicit Default impl and even then you have to explicitly add ..Default::defualt() when you're building the value.

I never thought that constructors were that burdensome and therefore do not understand the omission in other languages like Go and Rust that followed. Quite the opposite really -- knowing that a type always went through a predefined init was comforting to me when writing Java.