Rollup merge of #77203 - ecstatic-morse:const-stability-attr-checks, r=oli-obk

Check for missing const-stability attributes in `rustc_passes`

Currently, this happens as a side effect of `is_min_const_fn`, which is non-obvious. Also adds a test for this case, since we didn't seem to have one before.

compiler/rustc_mir/src/const_eval/fn_queries.rs

@@ -50,7 +50,7 @@ pub fn is_min_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
             None => {
                 if let Some(stab) = tcx.lookup_stability(def_id) {
                     if stab.level.is_stable() {
-                        tcx.sess.span_err(
+                        tcx.sess.delay_span_bug(
                             tcx.def_span(def_id),
                             "stable const functions must have either `rustc_const_stable` or \
                              `rustc_const_unstable` attribute",

compiler/rustc_mir/src/transform/check_consts/validation.rs

@@ -204,9 +204,6 @@ impl Validator<'mir, 'tcx> {
     pub fn check_body(&mut self) {
         let ConstCx { tcx, body, def_id, .. } = *self.ccx;
 
-        // HACK: This function has side-effects???? Make sure we call it.
-        let _ = crate::const_eval::is_min_const_fn(tcx, def_id.to_def_id());
-
         // The local type and predicate checks are not free and only relevant for `const fn`s.
         if self.const_kind() == hir::ConstContext::ConstFn {
             // Prevent const trait methods from being annotated as `stable`.