diff --git a/tests/compile-fail-fullmir/stacked_borrows/alias_through_mutation.rs b/tests/compile-fail-fullmir/stacked_borrows/alias_through_mutation.rs
index 092f3f09ed1..db9ac93279f 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/alias_through_mutation.rs
+++ b/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 _); }
diff --git a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut1.rs b/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut1.rs
index b82901985b7..9bced43f6e8 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut1.rs
+++ b/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;
diff --git a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut2.rs b/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut2.rs
index 69caddfa8c3..ea24f1bd274 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut2.rs
+++ b/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;
diff --git a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut3.rs b/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut3.rs
index d37f9e63f60..e564e878ddb 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut3.rs
+++ b/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;
diff --git a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut4.rs b/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut4.rs
index bf65d6e2303..15f67d0f872 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/aliasing_mut4.rs
+++ b/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;
diff --git a/tests/compile-fail-fullmir/stacked_borrows/buggy_split_at_mut.rs b/tests/compile-fail-fullmir/stacked_borrows/buggy_split_at_mut.rs
index a6daa5d93d7..959c6314690 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/buggy_split_at_mut.rs
+++ b/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;
 
diff --git a/tests/compile-fail-fullmir/stacked_borrows/illegal_write2.rs b/tests/compile-fail-fullmir/stacked_borrows/illegal_write2.rs
index f4fefaad5e2..ba3b6686b84 100644
--- a/tests/compile-fail-fullmir/stacked_borrows/illegal_write2.rs
+++ b/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 _;
diff --git a/tests/compile-fail/never_transmute_humans.rs b/tests/compile-fail/never_transmute_humans.rs
index 169e861be0b..34203338696 100644
--- a/tests/compile-fail/never_transmute_humans.rs
+++ b/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 }
diff --git a/tests/compile-fail/never_transmute_void.rs b/tests/compile-fail/never_transmute_void.rs
index 9c0165fed22..fab4981047f 100644
--- a/tests/compile-fail/never_transmute_void.rs
+++ b/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 {}
 
diff --git a/tests/compile-fail/validity/transmute_through_ptr.rs b/tests/compile-fail/validity/transmute_through_ptr.rs
index d6bc0305e69..4b6a3c95928 100644
--- a/tests/compile-fail/validity/transmute_through_ptr.rs
+++ b/tests/compile-fail/validity/transmute_through_ptr.rs
@@ -1,5 +1,3 @@
-#![allow(unused_variables)]
-
 #[repr(u32)]
 enum Bool { True }
 
diff --git a/tests/run-pass/dst-struct.rs b/tests/run-pass/dst-struct.rs
index 6ef0a6330f7..4c9e598e6ba 100644
--- a/tests/run-pass/dst-struct.rs
+++ b/tests/run-pass/dst-struct.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
-#![allow(unused_features)]
 #![feature(box_syntax)]
 
 struct Fat<T: ?Sized> {
diff --git a/tests/run-pass/issue-31267-additional.rs b/tests/run-pass/issue-31267-additional.rs
index 14e38f43c52..aaeeef8bf98 100644
--- a/tests/run-pass/issue-31267-additional.rs
+++ b/tests/run-pass/issue-31267-additional.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(unused_variables)]
-
 #[derive(Clone, Copy, Debug)]
 struct Bar;
 
@@ -25,5 +23,5 @@ impl Biz {
 }
 
 fn main() {
-    let foo = Biz::BAZ;
+    let _foo = Biz::BAZ;
 }
diff --git a/tests/run-pass/many_shr_bor.rs b/tests/run-pass/many_shr_bor.rs
index 393bafebfe4..d4901abb808 100644
--- a/tests/run-pass/many_shr_bor.rs
+++ b/tests/run-pass/many_shr_bor.rs
@@ -1,5 +1,4 @@
 // Make sure validation can handle many overlapping shared borrows for different parts of a data structure
-#![allow(unused_variables)]
 use std::cell::RefCell;
 
 struct Test {
@@ -25,9 +24,9 @@ fn test2(r: &mut RefCell<i32>) {
     let x = &*r; // releasing write lock, first suspension recorded
     let mut x_ref = x.borrow_mut();
     let x_inner : &mut i32 = &mut *x_ref; // new inner write lock, with same lifetime as outer lock
-    let x_inner_shr = &*x_inner; // releasing inner write lock, recording suspension
-    let y = &*r; // second suspension for the outer write lock
-    let x_inner_shr2 = &*x_inner; // 2nd suspension for inner write lock
+    let _x_inner_shr = &*x_inner; // releasing inner write lock, recording suspension
+    let _y = &*r; // second suspension for the outer write lock
+    let _x_inner_shr2 = &*x_inner; // 2nd suspension for inner write lock
 }
 
 fn main() {
diff --git a/tests/run-pass/move-arg-2-unique.rs b/tests/run-pass/move-arg-2-unique.rs
index d44c83763b7..77f763888ea 100644
--- a/tests/run-pass/move-arg-2-unique.rs
+++ b/tests/run-pass/move-arg-2-unique.rs
@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(unused_features, unused_variables)]
 #![feature(box_syntax)]
 
 fn test(foo: Box<Vec<isize>> ) { assert_eq!((*foo)[0], 10); }
diff --git a/tests/run-pass/move-arg-3-unique.rs b/tests/run-pass/move-arg-3-unique.rs
index 2e6320eb802..0754a3f60d3 100644
--- a/tests/run-pass/move-arg-3-unique.rs
+++ b/tests/run-pass/move-arg-3-unique.rs
@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(unused_features, unused_variables)]
 #![feature(box_syntax)]
 
 pub fn main() {
diff --git a/tests/run-pass/regions-lifetime-nonfree-late-bound.rs b/tests/run-pass/regions-lifetime-nonfree-late-bound.rs
index 96f1217a254..dfdf89c9c1c 100644
--- a/tests/run-pass/regions-lifetime-nonfree-late-bound.rs
+++ b/tests/run-pass/regions-lifetime-nonfree-late-bound.rs
@@ -22,7 +22,6 @@
 // doing region-folding, when really all clients of the region-folding
 // case only want to see FREE lifetime variables, not bound ones.
 
-#![allow(unused_features)]
 #![feature(box_syntax)]
 
 pub fn main() {