add test that relies on non-reborrowing-cast-to-raw

Author: RalfJung

tests/run-pass/stacked-borrows/stacked-borrows.rs

@@ -129,16 +129,15 @@ fn two_raw() { unsafe {
 } }
 
 // Make sure that creating a *mut does not invalidate existing shared references.
-fn shr_and_raw() { /* unsafe {
+fn shr_and_raw() { unsafe {
     use std::mem;
-    // FIXME: This is currently disabled because "as *mut _" incurs a reborrow.
     let x = &mut 0;
     let y1: &i32 = mem::transmute(&*x); // launder lifetimes
     let y2 = x as *mut _;
     let _val = *y1;
     *y2 += 1;
     // TODO: Once this works, add compile-fail test that tries to read from y1 again.
-} */ }
+} }
 
 fn disjoint_mutable_subborrows() {
     struct Foo {
@@ -165,5 +164,5 @@ fn disjoint_mutable_subborrows() {
     let b = unsafe{ borrow_field_b(ptr) };
     b.push(4);
     a.push_str(" world");
-    dbg!(a,b);
+    eprintln!("{:?} {:?}", a, b);
 }

tests/run-pass/stacked-borrows/stacked-borrows.stderr

@@ -1,7 +1 @@
-[$DIR/stacked-borrows.rs:168] a = "hello world"
-[$DIR/stacked-borrows.rs:168] b = [
-    0,
-    1,
-    2,
-    4,
-]
+"hello world" [0, 1, 2, 4]