Auto merge of #100456 - Dylan-DPC:rollup-fn17z9f, r=Dylan-DPC

Rollup of 9 pull requests

Successful merges:

 - #100022 (Optimize thread ID generation)
 - #100030 (cleanup code w/ pointers in std a little)
 - #100229 (add -Zextra-const-ub-checks to enable more UB checking in const-eval)
 - #100247 (Generalize trait object generic param check to aliases.)
 - #100255 (Adding more verbose documentation for `std::fmt::Write`)
 - #100366 (errors: don't fail on broken primary translations)
 - #100396 (Suggest const and static for global variable)
 - #100409 (rustdoc: don't generate DOM element for operator)
 - #100443 (Add two let else regression tests)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -236,6 +236,16 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
 
     const PANIC_ON_ALLOC_FAIL: bool = false; // will be raised as a proper error
 
+    #[inline(always)]
+    fn enforce_alignment(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
+        ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks
+    }
+
+    #[inline(always)]
+    fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
+        ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks
+    }
+
     fn load_mir(
         ecx: &InterpCx<'mir, 'tcx, Self>,
         instance: ty::InstanceDef<'tcx>,

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -436,24 +436,12 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
     type AllocExtra = ();
     type FrameExtra = ();
 
-    #[inline(always)]
-    fn enforce_alignment(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
-        // We do not check for alignment to avoid having to carry an `Align`
-        // in `ConstValue::ByRef`.
-        false
-    }
-
     #[inline(always)]
     fn force_int_for_alignment_check(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
         // We do not support `force_int`.
         false
     }
 
-    #[inline(always)]
-    fn enforce_validity(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
-        false // for now, we don't enforce validity
-    }
-
     #[inline(always)]
     fn enforce_number_init(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
         true