Merge from rustc

Author: The Miri Conjob Bot

src/diagnostics.rs

@@ -104,7 +104,7 @@ impl MachineStopType for TerminationInfo {
         self: Box<Self>,
         _: &mut dyn FnMut(
             std::borrow::Cow<'static, str>,
-            rustc_errors::DiagnosticArgValue<'static>,
+            rustc_errors::DiagnosticArgValue,
         ),
     ) {
     }

tests/pass/issues/issue-120337-irrefutable-let-ice.rs

@@ -0,0 +1,16 @@
+// Validation stops the test before the ICE we used to hit
+//@compile-flags: -Zmiri-disable-validation
+
+#![feature(never_type)]
+#[derive(Copy, Clone)]
+pub enum E {
+    A(!),
+}
+pub union U {
+    u: (),
+    e: E,
+}
+
+fn main() {
+    let E::A(ref _a) = unsafe { &(&U { u: () }).e };
+}