I don&#x27;t think so. Eric Lippert says its due to internal compiler limitations[1]. Though now that they rewrote the compiler and haven&#x27;t fixed it, who knows. Rust (incorrectly) deliberately requires type annotations for top-level items in the name of clarity. (Which ironically, makes it more difficult for beginners as they now have to make sure they got the type syntax correct just to write functions. Plus it adds visual noise that should be up to the programmer.)<p>As for things changing with type inference... if you run into that problem then add annotations. I&#x27;d be surprised if things continue to build after changing e.g. return types. I&#x27;d imagine this would only really be a problem with types that have implicit conversions (yet another reason to not have implicit conversions.)<p>1: <a href="http:&#x2F;&#x2F;blogs.msdn.com&#x2F;b&#x2F;ericlippert&#x2F;archive&#x2F;2009&#x2F;01&#x2F;26&#x2F;why-no-var-on-fields.aspx" rel="nofollow">http:&#x2F;&#x2F;blogs.msdn.com&#x2F;b&#x2F;ericlippert&#x2F;archive&#x2F;2009&#x2F;01&#x2F;26&#x2F;why-n...</a>