I can not agree with Rust being a functional programming language. I don’t think it has NO functional style idioms, but the borrow checking does not make it fun

I can not agree with Rust being a functional programming language. I don’t think it has NO functional style idioms, but the borrow checking does not make it functional. That would imply that the only characteristic of functional programming is some sort of ‘variable’ mutability constraint. I may not be up to defining functional programming by exclusion, I think any definition of functional programming includes things Rust does not have.