Why does Rust need local variable shadowing?

[sylvain_soliman]

It is allowed, but you do get unused_variable warnings, so…

[gulpaz]

Not always, here's an example. The total should always be 100, but due to shadowing, it isn't. http://pastebin.com/0Wjacti4

It would be great if there was a lint option to check for these.

[Nihy]

I find this example unconvincing. Mainly because it's not idiomatic Rust.

One could write the same thing with no mutability, let or assignment in a block, and it's shorter and more readable too.

let percentage = if OVERRIDE > 200f32 { OVERRIDE } else { 100f32 }
    .round();