Auto merge of #803 - christianpoveda:intptrcast-explicit-casts, r=Ral…

…fJung

Add tests for Intptrcast when doing explicit casts

r? @RalfJung

rust-version

@@ -1 +1 @@
-7e08576e4276a97b523c25bfd196d419c39c7b87
+088b987307b91612ab164026e1dcdd0129fdb62b

tests/run-pass-noseed/intptrcast.rs

@@ -1,8 +1,13 @@
 // compile-flags: -Zmiri-seed=0000000000000000
 
+// This returns a miri pointer at type usize, if the argument is a proper pointer
+fn transmute_ptr_to_int<T>(x: *const T) -> usize {
+    unsafe { std::mem::transmute(x) }
+}
+
 fn main() {
     // Some casting-to-int with arithmetic.
-    let x = &42 as *const i32 as usize; 
+    let x = &42 as *const i32 as usize;
     let y = x * 2;
     assert_eq!(y, x + x);
     let z = y as u8 as usize;
@@ -11,4 +16,11 @@ fn main() {
     // Pointer string formatting! We can't check the output as it changes when libstd changes,
     // but we can make sure Miri does not error.
     format!("{:?}", &mut 13 as *mut _);
+
+    // Check that intptrcast is triggered for explicit casts and that it is consistent with
+    // transmuting.
+    let a: *const i32 = &42;
+    let b = transmute_ptr_to_int(a) as u8;
+    let c = a as usize as u8;
+    assert_eq!(b, c);
 }

tests/run-pass-noseed/ptr_int_casts.rs

@@ -1,3 +1,4 @@
+// FIXME move this to run-pass, it should work with intptrcast.
 use std::mem;
 use std::ptr;
 

tests/run-pass/ptr_offset.rs → tests/run-pass-noseed/ptr_offset.rs

@@ -1,3 +1,5 @@
+// FIXME move this to run-pass, it should work with intptrcast.
+
 fn f() -> i32 { 42 }
 
 fn main() {