From 04a4df5f169c738a8c631874fa449d5107d52bbb Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Thu, 14 Sep 2023 11:47:11 +0200 Subject: [PATCH] add regression test for something we fixed --- ...issue-105536-const-val-roundtrip-ptr-eq.rs | 31 +++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 tests/ui/consts/issue-105536-const-val-roundtrip-ptr-eq.rs diff --git a/tests/ui/consts/issue-105536-const-val-roundtrip-ptr-eq.rs b/tests/ui/consts/issue-105536-const-val-roundtrip-ptr-eq.rs new file mode 100644 index 00000000000..1615399be32 --- /dev/null +++ b/tests/ui/consts/issue-105536-const-val-roundtrip-ptr-eq.rs @@ -0,0 +1,31 @@ +// run-pass + +// This does not reflect a stable guarantee (we guarantee very little for equality of pointers +// around `const`), but it would be good to understand what is happening if these assertions ever +// fail. +use std::ptr::NonNull; +use std::slice::from_raw_parts; + +const PTR_U8: *const u8 = NonNull::dangling().as_ptr(); +const CONST_U8_REF: &[u8] = unsafe { from_raw_parts(PTR_U8, 0) }; +const CONST_U8_PTR: *const u8 = unsafe { from_raw_parts(PTR_U8, 0).as_ptr() }; +static STATIC_U8_REF: &[u8] = unsafe { from_raw_parts(PTR_U8, 0) }; + +const PTR_U16: *const u16 = NonNull::dangling().as_ptr(); +const CONST_U16_REF: &[u16] = unsafe { from_raw_parts(PTR_U16, 0) }; + +const fn const_u8_fn() -> &'static [u8] { + unsafe { from_raw_parts(PTR_U8, 0) } +} + +fn main() { + let ptr_u8 = unsafe { from_raw_parts(PTR_U8, 0) }.as_ptr(); + let ptr_u16 = unsafe { from_raw_parts(PTR_U16, 0) }.as_ptr(); + + assert_eq!(ptr_u8, PTR_U8); + assert_eq!(ptr_u8, CONST_U8_PTR); + assert_eq!(ptr_u8, const_u8_fn().as_ptr()); + assert_eq!(ptr_u8, STATIC_U8_REF.as_ptr()); + assert_eq!(ptr_u16, CONST_U16_REF.as_ptr()); + assert_eq!(ptr_u8, CONST_U8_REF.as_ptr()); +}