1 files changed, 65 insertions, 0 deletions
diff --git a/src/test/ui/consts/const-eval/ub-ref-ptr.rs b/src/test/ui/consts/const-eval/ub-ref-ptr.rs
new file mode 100644
index 000000000..d0216f746
--- /dev/null
+++ b/src/test/ui/consts/const-eval/ub-ref-ptr.rs
@@ -0,0 +1,65 @@
+// ignore-tidy-linelength
+// stderr-per-bitwidth
+#![allow(invalid_value)]
+
+use std::mem;
+
+#[repr(C)]
+union MaybeUninit<T: Copy> {
+    uninit: (),
+    init: T,
+}
+
+const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
+//~^ ERROR it is undefined behavior to use this value
+//~| constructing invalid value: encountered an unaligned reference (required 2 byte alignment but found 1)
+
+const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
+//~^ ERROR it is undefined behavior to use this value
+//~| constructing invalid value: encountered an unaligned box (required 2 byte alignment but found 1)
+
+const NULL: &u16 = unsafe { mem::transmute(0usize) };
+//~^ ERROR it is undefined behavior to use this value
+
+const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
+//~^ ERROR it is undefined behavior to use this value
+
+
+// It is very important that we reject this: We do promote `&(4 * REF_AS_USIZE)`,
+// but that would fail to compile; so we ended up breaking user code that would
+// have worked fine had we not promoted.
+const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+
+const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+//~| ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+
+const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+//~| ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+
+const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
+//~^ ERROR it is undefined behavior to use this value
+
+const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
+//~^ ERROR it is undefined behavior to use this value
+
+const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
+//~^ ERROR it is undefined behavior to use this value
+
+const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
+//~^ ERROR it is undefined behavior to use this value
+const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
+//~^ ERROR it is undefined behavior to use this value
+const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
+//~^ ERROR it is undefined behavior to use this value
+const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
+//~^ ERROR it is undefined behavior to use this value
+
+fn main() {}