Only suggest casting numeric types using into()

src/test/ui/mismatched_types/issue-26480.stderr

@@ -6,10 +6,6 @@ error[E0308]: mismatched types
 ...
 37 |     write!(hello);
    |     -------------- in this macro invocation
-help: you can cast an `usize` to `u64`, which will truncate or zero-extend depending on the bit width of `usize`
-   |
-26 |                   ($arr.len() * size_of($arr[0])) as u64); //~ ERROR mismatched types
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0605]: non-primitive cast: `{integer}` as `()`
   --> $DIR/issue-26480.rs:32:19

src/test/ui/suggestions/numeric-cast-2.rs

@@ -12,7 +12,9 @@ fn foo() -> i32 {
     4
 }
 fn main() {
-    let x: u32 = foo();
+    let x: u16 = foo();
+    //~^ ERROR mismatched types
+    let y: i64 = x + x;
     //~^ ERROR mismatched types
     let z: i32 = x + x;
     //~^ ERROR mismatched types

src/test/ui/suggestions/numeric-cast-2.stderr

@@ -1,22 +1,20 @@
 error[E0308]: mismatched types
   --> $DIR/numeric-cast-2.rs:15:18
    |
-15 |     let x: u32 = foo();
-   |                  ^^^^^ expected u32, found i32
-help: you can cast an `i32` to `u32`, which will sign-extend the source value
-   |
-15 |     let x: u32 = foo() as u32;
-   |                  ^^^^^^^^^^^^
+15 |     let x: u16 = foo();
+   |                  ^^^^^ expected u16, found i32
 
 error[E0308]: mismatched types
   --> $DIR/numeric-cast-2.rs:17:18
    |
-17 |     let z: i32 = x + x;
-   |                  ^^^^^ expected i32, found u32
-help: you can cast an `u32` to `i32`, which will truncate the source value
+17 |     let y: i64 = x + x;
+   |                  ^^^^^ expected i64, found u16
+
+error[E0308]: mismatched types
+  --> $DIR/numeric-cast-2.rs:19:18
    |
-17 |     let z: i32 = (x + x) as i32;
-   |                  ^^^^^^^^^^^^^^
+19 |     let z: i32 = x + x;
+   |                  ^^^^^ expected i32, found u16
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 

src/test/ui/suggestions/numeric-cast.rs

@@ -46,10 +46,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<usize>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<usize>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<isize>(x_usize);
     //~^ ERROR mismatched types
@@ -72,10 +70,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<isize>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<isize>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<u64>(x_usize);
     //~^ ERROR mismatched types
@@ -98,10 +94,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<u64>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<u64>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<i64>(x_usize);
     //~^ ERROR mismatched types
@@ -124,10 +118,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<i64>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<i64>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<u32>(x_usize);
     //~^ ERROR mismatched types
@@ -150,10 +142,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<u32>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<u32>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<i32>(x_usize);
     //~^ ERROR mismatched types
@@ -176,10 +166,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<i32>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<i32>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<u16>(x_usize);
     //~^ ERROR mismatched types
@@ -202,10 +190,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<u16>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<u16>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<i16>(x_usize);
     //~^ ERROR mismatched types
@@ -228,10 +214,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<i16>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<i16>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<u8>(x_usize);
     //~^ ERROR mismatched types
@@ -254,10 +238,8 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<u8>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<u8>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<i8>(x_usize);
     //~^ ERROR mismatched types
@@ -280,10 +262,8 @@ fn main() {
     foo::<i8>(x_i8);
     foo::<i8>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
     foo::<i8>(x_f32);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause Undefined Behavior
 
     foo::<f64>(x_usize);
     //~^ ERROR mismatched types
@@ -331,6 +311,5 @@ fn main() {
     //~^ ERROR mismatched types
     foo::<f32>(x_f64);
     //~^ ERROR mismatched types
-    //~| WARN casting here will cause undefined behavior
     foo::<f32>(x_f32);
 }