for bindings in macros can shadow function args

[kmcallister]

#![feature(macro_rules)]

macro_rules! print_five_times( ($e:expr) => (
    for i in range(0, 5u) {
        println!("{:u}: {}", i, $e);
    }
))

fn f(i: &'static str) {
    print_five_times!(i);
}

fn main() {
    f("Hello, world!");
}

produces

0: 0
1: 1
2: 2
3: 3
4: 4

Renaming f's argument to x produces the expected

0: Hello, world!
1: Hello, world!
2: Hello, world!
3: Hello, world!
4: Hello, world!

Interestingly, so does

fn f(x: &'static str) {
    let i = x;       
    print_five_times!(i);
}

rustc 0.11.0-pre (81c0223 2014-05-29 16:41:42 -0700)
host: x86_64-unknown-linux-gnu

[alexcrichton]

Closing as a dupe of either #9383 or #9384