remove a whole lot of unnecessary attributes

Author: RalfJung

tests/compile-fail-fullmir/stacked_borrows/alias_through_mutation.rs

@@ -1,5 +1,3 @@
-#![allow(unused_variables)]
-
 // This makes a ref that was passed to us via &mut alias with things it should not alias with
 fn retarget(x: &mut &u32, target: &mut u32) {
     unsafe { *x = &mut *(target as *mut _); }

tests/compile-fail-fullmir/stacked_borrows/aliasing_mut1.rs

@@ -1,8 +1,6 @@
-#![allow(unused_variables)]
-
 use std::mem;
 
-pub fn safe(x: &mut i32, y: &mut i32) {} //~ ERROR barrier
+pub fn safe(_x: &mut i32, _y: &mut i32) {} //~ ERROR barrier
 
 fn main() {
     let mut x = 0;

tests/compile-fail-fullmir/stacked_borrows/aliasing_mut2.rs

@@ -1,8 +1,6 @@
-#![allow(unused_variables)]
-
 use std::mem;
 
-pub fn safe(x: &i32, y: &mut i32) {} //~ ERROR barrier
+pub fn safe(_x: &i32, _y: &mut i32) {} //~ ERROR barrier
 
 fn main() {
     let mut x = 0;

tests/compile-fail-fullmir/stacked_borrows/aliasing_mut3.rs

@@ -1,8 +1,6 @@
-#![allow(unused_variables)]
-
 use std::mem;
 
-pub fn safe(x: &mut i32, y: &i32) {} //~ ERROR does not exist on the stack
+pub fn safe(_x: &mut i32, _y: &i32) {} //~ ERROR does not exist on the stack
 
 fn main() {
     let mut x = 0;

tests/compile-fail-fullmir/stacked_borrows/aliasing_mut4.rs

@@ -1,10 +1,8 @@
-#![allow(unused_variables)]
-
 use std::mem;
 use std::cell::Cell;
 
 // Make sure &mut UnsafeCell also is exclusive
-pub fn safe(x: &i32, y: &mut Cell<i32>) {} //~ ERROR barrier
+pub fn safe(_x: &i32, _y: &mut Cell<i32>) {} //~ ERROR barrier
 
 fn main() {
     let mut x = 0;

tests/compile-fail-fullmir/stacked_borrows/buggy_split_at_mut.rs

@@ -1,5 +1,3 @@
-#![allow(unused_variables)]
-
 mod safe {
     use std::slice::from_raw_parts_mut;
 

tests/compile-fail-fullmir/stacked_borrows/illegal_write2.rs

@@ -1,5 +1,3 @@
-#![allow(unused_variables)]
-
 fn main() {
     let target = &mut 42;
     let target2 = target as *mut _;

tests/compile-fail/never_transmute_humans.rs

@@ -2,17 +2,12 @@
 // compile-flags: -Zmiri-disable-validation
 
 #![feature(never_type)]
-#![allow(unreachable_code)]
-#![allow(unused_variables)]
 
 struct Human;
 
 fn main() {
-    let x: ! = unsafe {
+    let _x: ! = unsafe {
         std::mem::transmute::<Human, !>(Human) //~ ERROR constant evaluation error
         //^~ NOTE entered unreachable code
     };
-    f(x)
 }
-
-fn f(x: !) -> ! { x }

tests/compile-fail/never_transmute_void.rs

@@ -2,8 +2,6 @@
 // compile-flags: -Zmiri-disable-validation
 
 #![feature(never_type)]
-#![allow(unreachable_code)]
-#![allow(unused_variables)]
 
 enum Void {}
 

tests/compile-fail/validity/transmute_through_ptr.rs

@@ -1,5 +1,3 @@
-#![allow(unused_variables)]
-
 #[repr(u32)]
 enum Bool { True }