Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0569.md b/compiler/rustc_error_codes/src/error_codes/E0569.md
new file mode 100644
index 000000000..2ca2b57ec
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0569.md
@@ -0,0 +1,18 @@
+If an impl has a generic parameter with the `#[may_dangle]` attribute, then
+that impl must be declared as an `unsafe impl`.
+
+Erroneous code example:
+
+```compile_fail,E0569
+#![feature(dropck_eyepatch)]
+
+struct Foo<X>(X);
+impl<#[may_dangle] X> Drop for Foo<X> {
+    fn drop(&mut self) { }
+}
+```
+
+In this example, we are asserting that the destructor for `Foo` will not
+access any data of type `X`, and require this assertion to be true for
+overall safety in our program. The compiler does not currently attempt to
+verify this assertion; therefore we must tag this `impl` as unsafe.