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]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/test/debuginfo/function-arg-initialization.rs b/src/test/debuginfo/function-arg-initialization.rs
index d439f49fe69..535efa0b84e 100644
--- a/src/test/debuginfo/function-arg-initialization.rs
+++ b/src/test/debuginfo/function-arg-initialization.rs
@@ -155,7 +155,7 @@ fn non_immediate_args(a: BigStruct, b: BigStruct) {
 }
 
 fn binding(a: i64, b: u64, c: f64) {
-    let x = 0;
+    let x = 0i;
 }
 
 fn assignment(mut a: u64, b: u64, c: f64) {