1 files changed, 165 insertions, 0 deletions
diff --git a/src/test/ui/consts/const-eval/ub-wide-ptr.rs b/src/test/ui/consts/const-eval/ub-wide-ptr.rs
new file mode 100644
index 000000000..a0377ab1e
--- /dev/null
+++ b/src/test/ui/consts/const-eval/ub-wide-ptr.rs
@@ -0,0 +1,165 @@
+// stderr-per-bitwidth
+// ignore-tidy-linelength
+#![allow(unused)]
+
+use std::mem;
+
+// normalize-stderr-test "offset \d+" -> "offset N"
+// normalize-stderr-test "alloc\d+" -> "allocN"
+// normalize-stderr-test "size \d+" -> "size N"
+
+/// A newtype wrapper to prevent MIR generation from inserting reborrows that would affect the error
+/// message. Use this whenever the message is "any use of this value will cause an error" instead of
+/// "it is undefined behavior to use this value".
+#[repr(transparent)]
+struct W<T>(T);
+
+#[repr(C)]
+union MaybeUninit<T: Copy> {
+    uninit: (),
+    init: T,
+}
+
+trait Trait {}
+impl Trait for bool {}
+
+// custom unsized type
+struct MyStr(str);
+
+// custom unsized type with sized fields
+struct MySlice<T: ?Sized>(bool, T);
+type MySliceBool = MySlice<[bool]>;
+
+// # str
+// OK
+const STR_VALID: &str = unsafe { mem::transmute((&42u8, 1usize)) };
+// bad str
+const STR_TOO_LONG: &str = unsafe { mem::transmute((&42u8, 999usize)) };
+//~^ ERROR it is undefined behavior to use this value
+const NESTED_STR_MUCH_TOO_LONG: (&str,) = (unsafe { mem::transmute((&42, usize::MAX)) },);
+//~^ ERROR it is undefined behavior to use this value
+// bad str
+const STR_LENGTH_PTR: &str = unsafe { mem::transmute((&42u8, &3)) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+// bad str in user-defined unsized type
+const MY_STR_LENGTH_PTR: &MyStr = unsafe { mem::transmute((&42u8, &3)) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+const MY_STR_MUCH_TOO_LONG: &MyStr = unsafe { mem::transmute((&42u8, usize::MAX)) };
+//~^ ERROR it is undefined behavior to use this value
+
+// uninitialized byte
+const STR_NO_INIT: &str = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
+//~^ ERROR it is undefined behavior to use this value
+// uninitialized byte in user-defined str-like
+const MYSTR_NO_INIT: &MyStr = unsafe { mem::transmute::<&[_], _>(&[MaybeUninit::<u8> { uninit: () }]) };
+//~^ ERROR it is undefined behavior to use this value
+
+// # slice
+// OK
+const SLICE_VALID: &[u8] = unsafe { mem::transmute((&42u8, 1usize)) };
+// bad slice: length uninit
+const SLICE_LENGTH_UNINIT: &[u8] = unsafe {
+//~^ ERROR it is undefined behavior to use this value
+    let uninit_len = MaybeUninit::<usize> { uninit: () };
+    mem::transmute((42, uninit_len))
+};
+// bad slice: length too big
+const SLICE_TOO_LONG: &[u8] = unsafe { mem::transmute((&42u8, 999usize)) };
+//~^ ERROR it is undefined behavior to use this value
+// bad slice: length computation overflows
+const SLICE_TOO_LONG_OVERFLOW: &[u32] = unsafe { mem::transmute((&42u32, isize::MAX)) };
+//~^ ERROR it is undefined behavior to use this value
+// bad slice: length not an int
+const SLICE_LENGTH_PTR: &[u8] = unsafe { mem::transmute((&42u8, &3)) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+// bad slice box: length too big
+const SLICE_TOO_LONG_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, 999usize)) };
+//~^ ERROR it is undefined behavior to use this value
+// bad slice box: length not an int
+const SLICE_LENGTH_PTR_BOX: Box<[u8]> = unsafe { mem::transmute((&42u8, &3)) };
+//~^ ERROR any use of this value will cause an error
+//~| WARN this was previously accepted by the compiler but is being phased out
+
+// bad data *inside* the slice
+const SLICE_CONTENT_INVALID: &[bool] = &[unsafe { mem::transmute(3u8) }];
+//~^ ERROR it is undefined behavior to use this value
+//~| ERROR any use of this value will cause an error
+//~| WARNING this was previously accepted
+
+// good MySliceBool
+const MYSLICE_GOOD: &MySliceBool = &MySlice(true, [false]);
+// bad: sized field is not okay
+const MYSLICE_PREFIX_BAD: &MySliceBool = &MySlice(unsafe { mem::transmute(3u8) }, [false]);
+//~^ ERROR it is undefined behavior to use this value
+//~| ERROR any use of this value will cause an error
+//~| WARNING this was previously accepted
+// bad: unsized part is not okay
+const MYSLICE_SUFFIX_BAD: &MySliceBool = &MySlice(true, [unsafe { mem::transmute(3u8) }]);
+//~^ ERROR it is undefined behavior to use this value
+//~| ERROR any use of this value will cause an error
+//~| WARNING this was previously accepted
+
+// # raw slice
+const RAW_SLICE_VALID: *const [u8] = unsafe { mem::transmute((&42u8, 1usize)) }; // ok
+const RAW_SLICE_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, 999usize)) }; // ok because raw
+const RAW_SLICE_MUCH_TOO_LONG: *const [u8] = unsafe { mem::transmute((&42u8, usize::MAX)) }; // ok because raw
+const RAW_SLICE_LENGTH_UNINIT: *const [u8] = unsafe {
+//~^ ERROR it is undefined behavior to use this value
+    let uninit_len = MaybeUninit::<usize> { uninit: () };
+    mem::transmute((42, uninit_len))
+};
+
+// # trait object
+// bad trait object
+const TRAIT_OBJ_SHORT_VTABLE_1: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u8))) };
+//~^ ERROR it is undefined behavior to use this value
+//~| expected a vtable
+// bad trait object
+const TRAIT_OBJ_SHORT_VTABLE_2: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &3u64))) };
+//~^ ERROR it is undefined behavior to use this value
+//~| expected a vtable
+// bad trait object
+const TRAIT_OBJ_INT_VTABLE: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, 4usize))) };
+//~^ ERROR it is undefined behavior to use this value
+//~| expected a vtable
+const TRAIT_OBJ_UNALIGNED_VTABLE: &dyn Trait = unsafe { mem::transmute((&92u8, &[0u8; 128])) };
+//~^ ERROR evaluation of constant value failed
+//~| does not point to a vtable
+const TRAIT_OBJ_BAD_DROP_FN_NULL: &dyn Trait = unsafe { mem::transmute((&92u8, &[0usize; 8])) };
+//~^ ERROR evaluation of constant value failed
+//~| does not point to a vtable
+const TRAIT_OBJ_BAD_DROP_FN_INT: &dyn Trait = unsafe { mem::transmute((&92u8, &[1usize; 8])) };
+//~^ ERROR evaluation of constant value failed
+//~| does not point to a vtable
+const TRAIT_OBJ_BAD_DROP_FN_NOT_FN_PTR: W<&dyn Trait> = unsafe { mem::transmute(W((&92u8, &[&42u8; 8]))) };
+//~^ ERROR it is undefined behavior to use this value
+//~| expected a vtable
+
+// bad data *inside* the trait object
+const TRAIT_OBJ_CONTENT_INVALID: &dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) };
+//~^ ERROR it is undefined behavior to use this value
+//~| expected a boolean
+
+// # raw trait object
+const RAW_TRAIT_OBJ_VTABLE_NULL: *const dyn Trait = unsafe { mem::transmute((&92u8, 0usize)) };
+//~^ ERROR evaluation of constant value failed
+//~| null pointer
+const RAW_TRAIT_OBJ_VTABLE_INVALID: *const dyn Trait = unsafe { mem::transmute((&92u8, &3u64)) };
+//~^ ERROR evaluation of constant value failed
+//~| does not point to a vtable
+const RAW_TRAIT_OBJ_CONTENT_INVALID: *const dyn Trait = unsafe { mem::transmute::<_, &bool>(&3u8) } as *const dyn Trait; // ok because raw
+
+// Const eval fails for these, so they need to be statics to error.
+static mut RAW_TRAIT_OBJ_VTABLE_NULL_THROUGH_REF: *const dyn Trait = unsafe {
+    mem::transmute::<_, &dyn Trait>((&92u8, 0usize))
+    //~^ ERROR could not evaluate static initializer
+};
+static mut RAW_TRAIT_OBJ_VTABLE_INVALID_THROUGH_REF: *const dyn Trait = unsafe {
+    mem::transmute::<_, &dyn Trait>((&92u8, &3u64))
+    //~^ ERROR could not evaluate static initializer
+};
+
+fn main() {}