librustc: Remove the fallback to `int` for integers and `f64` for

floating point numbers for real.

This will break code that looks like:

    let mut x = 0;
    while ... {
        x += 1;
    }
    println!("{}", x);

Change that code to:

    let mut x = 0i;
    while ... {
        x += 1;
    }
    println!("{}", x);

Closes #15201.

[breaking-change]

2 files changed, 2 insertions, 2 deletions

diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 1a66d952e9b..1096758a22d 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -686,7 +686,7 @@ macro_rules! tuple (
             fn fmt(&self, f: &mut Formatter) -> Result {
                 try!(write!(f, "("));
                 let ($(ref $name,)*) = *self;
-                let mut n = 0;
+                let mut n = 0i;
                 $(
                     if n > 0 {
                         try!(write!(f, ", "));
diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs
index 56d0817dd00..d3edfd42feb 100644
--- a/src/libcore/fmt/num.rs
+++ b/src/libcore/fmt/num.rs
@@ -388,7 +388,7 @@ mod tests {
     #[test]
     #[should_fail]
     fn test_radix_base_too_large() {
-        let _ = radix(55, 37);
+        let _ = radix(55i, 37);
     }
 }