Allow unused tuple struct fields in Miri tests

Otherwise the newly-detected dead code causes new output

Author: shepmaster

src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.rs

@@ -3,7 +3,7 @@
 
 //@[stack]error-in-other-file: which is strongly protected
 //@[tree]error-in-other-file: /deallocation through .* is forbidden/
-struct Newtype<'a>(&'a mut i32, i32);
+struct Newtype<'a>(#[allow(dead_code)] &'a mut i32, #[allow(dead_code)] i32);
 
 fn dealloc_while_running(_n: Newtype<'_>, dealloc: impl FnOnce()) {
     dealloc();

src/tools/miri/tests/fail/both_borrows/newtype_retagging.rs

@@ -4,7 +4,7 @@
 //@[stack]error-in-other-file: which is strongly protected
 //@[tree]error-in-other-file: /deallocation through .* is forbidden/
 
-struct Newtype<'a>(&'a mut i32);
+struct Newtype<'a>(#[allow(dead_code)] &'a mut i32);
 
 fn dealloc_while_running(_n: Newtype<'_>, dealloc: impl FnOnce()) {
     dealloc();

src/tools/miri/tests/fail/concurrency/read_only_atomic_load_large.rs

@@ -6,7 +6,7 @@
 use std::sync::atomic::{AtomicI64, Ordering};
 
 #[repr(align(8))]
-struct AlignedI64(i64);
+struct AlignedI64(#[allow(dead_code)] i64);
 
 fn main() {
     static X: AlignedI64 = AlignedI64(0);

src/tools/miri/tests/fail/dangling_pointers/dyn_size.rs

@@ -1,7 +1,7 @@
 // should find the bug even without retagging
 //@compile-flags: -Zmiri-disable-stacked-borrows
 
-struct SliceWithHead(u8, [u8]);
+struct SliceWithHead(#[allow(dead_code)] u8, #[allow(dead_code)] [u8]);
 
 fn main() {
     let buf = [0u32; 1];

src/tools/miri/tests/fail/function_pointers/abi_mismatch_array_vs_struct.rs

@@ -3,7 +3,7 @@
 // Some targets treat arrays and structs very differently. We would probably catch that on those
 // targets since we check the `PassMode`; here we ensure that we catch it on *all* targets
 // (in particular, on x86-64 the pass mode is `Indirect` for both of these).
-struct S(i32, i32, i32, i32);
+struct S(#[allow(dead_code)] i32, #[allow(dead_code)] i32, #[allow(dead_code)] i32, #[allow(dead_code)] i32);
 type A = [i32; 4];
 
 fn main() {

src/tools/miri/tests/fail/issue-miri-1112.rs

@@ -1,7 +1,7 @@
 trait Empty {}
 
 #[repr(transparent)]
-pub struct FunnyPointer(dyn Empty);
+pub struct FunnyPointer(#[allow(dead_code)] dyn Empty);
 
 #[repr(C)]
 pub struct Meta {

src/tools/miri/tests/fail/unaligned_pointers/drop_in_place.rs

@@ -1,7 +1,7 @@
 //@compile-flags: -Cdebug-assertions=no
 
 #[repr(transparent)]
-struct HasDrop(u8);
+struct HasDrop(#[allow(dead_code)] u8);
 
 impl Drop for HasDrop {
     fn drop(&mut self) {}

src/tools/miri/tests/fail/unaligned_pointers/promise_alignment.rs

@@ -7,7 +7,7 @@ mod utils;
 
 #[repr(align(8))]
 #[derive(Copy, Clone)]
-struct Align8(u64);
+struct Align8(#[allow(dead_code)] u64);
 
 fn main() {
     let buffer = [0u32; 128]; // get some 4-aligned memory
@@ -35,7 +35,7 @@ fn main() {
     if cfg!(read_unaligned_ptr) {
         #[repr(align(16))]
         #[derive(Copy, Clone)]
-        struct Align16(u128);
+        struct Align16(#[allow(dead_code)] u128);
 
         let align16 = if align8.addr() % 16 == 0 { align8 } else { align8.wrapping_add(2) };
         assert!(align16.addr() % 16 == 0);

src/tools/miri/tests/pass/align_offset_symbolic.rs

@@ -46,7 +46,7 @@ fn test_align_to() {
     {
         #[repr(align(8))]
         #[derive(Copy, Clone)]
-        struct Align8(u64);
+        struct Align8(#[allow(dead_code)] u64);
 
         let (_l, m, _r) = unsafe { s.align_to::<Align8>() };
         assert!(m.len() > 0);
@@ -97,7 +97,7 @@ fn huge_align() {
     const SIZE: usize = 1 << 30;
     #[cfg(target_pointer_width = "16")]
     const SIZE: usize = 1 << 13;
-    struct HugeSize([u8; SIZE - 1]);
+    struct HugeSize(#[allow(dead_code)] [u8; SIZE - 1]);
     let _ = std::ptr::invalid::<HugeSize>(SIZE).align_offset(SIZE);
 }
 

src/tools/miri/tests/pass/box-custom-alloc.rs

@@ -57,7 +57,7 @@ fn test1() {
 }
 
 // Make the allocator itself so big that the Box is not even a ScalarPair any more.
-struct OnceAllocRef<'s, 'a>(&'s OnceAlloc<'a>, u64);
+struct OnceAllocRef<'s, 'a>(&'s OnceAlloc<'a>, #[allow(dead_code)] u64);
 
 unsafe impl<'shared, 'a: 'shared> Allocator for OnceAllocRef<'shared, 'a> {
     fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {