upstream rustc_codegen_ssa/rustc_middle changes for enzyme/autodiff

compiler/rustc_middle/messages.ftl

@@ -32,6 +32,8 @@ middle_assert_shl_overflow =
 middle_assert_shr_overflow =
     attempt to shift right by `{$val}`, which would overflow
 
+middle_autodiff_unsafe_inner_const_ref = reading from a `Duplicated` const {$ty} is unsafe
+
 middle_bounds_check =
     index out of bounds: the length is {$len} but the index is {$index}
 
@@ -107,6 +109,8 @@ middle_type_length_limit = reached the type-length limit while instantiating `{$
 middle_unknown_layout =
     the type `{$ty}` has an unknown layout
 
+middle_unsupported_union = we don't support unions yet: '{$ty_name}'
+
 middle_values_too_big =
     values of the type `{$ty}` are too big for the target architecture