fix sus provenance in tests/smoke.rs for miri

tests/smoke.rs

@@ -1,4 +1,5 @@
 use backtrace::Frame;
+use core::ffi::c_void;
 use std::ptr;
 use std::thread;
 
@@ -249,11 +250,11 @@ fn sp_smoke_test() {
     return;
 
     #[inline(never)]
-    fn recursive_stack_references(refs: &mut Vec<usize>) {
+    fn recursive_stack_references(refs: &mut Vec<*mut c_void>) {
         assert!(refs.len() < 5);
 
-        let x = refs.len();
-        refs.push(ptr::addr_of!(x) as usize);
+        let mut x = refs.len();
+        refs.push(ptr::addr_of_mut!(x).cast());
 
         if refs.len() < 5 {
             recursive_stack_references(refs);
@@ -271,7 +272,7 @@ fn sp_smoke_test() {
     // mangled names.
 
     fn make_trace_closure<'a>(
-        refs: &'a mut Vec<usize>,
+        refs: &'a mut Vec<*mut c_void>,
     ) -> impl FnMut(&backtrace::Frame) -> bool + 'a {
         let mut child_sp = None;
         let mut child_ref = None;
@@ -289,9 +290,9 @@ fn sp_smoke_test() {
                         })
             });
 
-            let sp = frame.sp() as usize;
-            eprintln!("sp  = {:p}", sp as *const u8);
-            if sp == 0 {
+            let sp = frame.sp();
+            eprintln!("sp  = {sp:p}");
+            if sp as usize == 0 {
                 // If the SP is null, then we don't have an implementation for
                 // getting the SP on this target. Just keep walking the stack,
                 // but don't make our assertions about the on-stack pointers and
@@ -306,8 +307,8 @@ fn sp_smoke_test() {
 
             if is_recursive_stack_references {
                 let r = refs.pop().unwrap();
-                eprintln!("ref = {:p}", r as *const u8);
-                if sp != 0 {
+                eprintln!("ref = {:p}", r);
+                if sp as usize != 0 {
                     assert!(r > sp);
                     if let Some(child_ref) = child_ref {
                         assert!(sp >= child_ref);