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]

3 files changed, 3 insertions, 3 deletions

diff --git a/src/libserialize/base64.rs b/src/libserialize/base64.rs
index ee1e836112e..63cfbd6d9aa 100644
--- a/src/libserialize/base64.rs
+++ b/src/libserialize/base64.rs
@@ -208,7 +208,7 @@ impl<'a> FromBase64 for &'a str {
     fn from_base64(&self) -> Result<Vec<u8>, FromBase64Error> {
         let mut r = Vec::new();
         let mut buf: u32 = 0;
-        let mut modulus = 0;
+        let mut modulus = 0i;
 
         let mut it = self.bytes().enumerate();
         for (idx, byte) in it {
diff --git a/src/libserialize/hex.rs b/src/libserialize/hex.rs
index 2fccbc2fcaf..51fab7b1354 100644
--- a/src/libserialize/hex.rs
+++ b/src/libserialize/hex.rs
@@ -104,7 +104,7 @@ impl<'a> FromHex for &'a str {
     fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
         // This may be an overestimate if there is any whitespace
         let mut b = Vec::with_capacity(self.len() / 2);
-        let mut modulus = 0;
+        let mut modulus = 0i;
         let mut buf = 0u8;
 
         for (idx, byte) in self.bytes().enumerate() {
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 9c91bd4b7e1..d8dd2938b34 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -3424,7 +3424,7 @@ mod tests {
         hash_map.insert("a".to_string(), 1i);
         hash_map.insert("b".to_string(), 2);
         assert_eq!(hash_map.to_json(), object);
-        assert_eq!(Some(15i).to_json(), Number(15 as f64));
+        assert_eq!(Some(15i).to_json(), Number(15f64));
         assert_eq!(None::<int>.to_json(), Null);
     }