diff --git a/tests/run-pass/transmute_fat.rs b/tests/run-pass/transmute_fat.rs new file mode 100644 index 000000000000..ec887902d054 --- /dev/null +++ b/tests/run-pass/transmute_fat.rs @@ -0,0 +1,10 @@ +fn main() { + // If we are careful, we can exploit data layout... + let raw = unsafe { + std::mem::transmute::<&[u8], [usize; 2]>(&[42]) + }; + let ptr = raw[0] + raw[1]; + let ptr = ptr as *const u8; + // The pointer is one-past-the end, but we decrement it into bounds before using it + assert_eq!(unsafe { *ptr.offset(-1) }, 42); +}