Auto merge of #83376 - Dylan-DPC:rollup-s2fsjwj, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - #82374 (Add license metadata for std dependencies)
 - #82683 (Document panicking cases for integer division and remainder)
 - #83272 (Clarify non-exact length in the Iterator::take documentation)
 - #83338 (Fix test for #82270)
 - #83351 (post-drop-elab check-const: explain why we still check qualifs)
 - #83367 (Improve error message for unassigned query provider)
 - #83372 (SplitInclusive is public API)

Failed merges:

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

2 files changed, 12 insertions, 3 deletions

diff --git a/compiler/rustc_middle/src/ty/query/mod.rs b/compiler/rustc_middle/src/ty/query/mod.rs
index 48e777f7158..c170858ba85 100644
--- a/compiler/rustc_middle/src/ty/query/mod.rs
+++ b/compiler/rustc_middle/src/ty/query/mod.rs
@@ -217,8 +217,11 @@ macro_rules! define_callbacks {
             fn default() -> Self {
                 Providers {
                     $($name: |_, key| bug!(
-                        "`tcx.{}({:?})` unsupported by its crate",
-                         stringify!($name), key
+                        "`tcx.{}({:?})` unsupported by its crate; \
+                         perhaps the `{}` query was never assigned a provider function",
+                        stringify!($name),
+                        key,
+                        stringify!($name),
                     ),)*
                 }
             }
diff --git a/compiler/rustc_mir/src/transform/check_consts/post_drop_elaboration.rs b/compiler/rustc_mir/src/transform/check_consts/post_drop_elaboration.rs
index 1a2d932ba19..057092b8ef5 100644
--- a/compiler/rustc_mir/src/transform/check_consts/post_drop_elaboration.rs
+++ b/compiler/rustc_mir/src/transform/check_consts/post_drop_elaboration.rs
@@ -79,7 +79,9 @@ impl Visitor<'tcx> for CheckLiveDrops<'mir, 'tcx> {
             mir::TerminatorKind::Drop { place: dropped_place, .. } => {
                 let dropped_ty = dropped_place.ty(self.body, self.tcx).ty;
                 if !NeedsDrop::in_any_value_of_ty(self.ccx, dropped_ty) {
-                    return;
+                    bug!(
+                        "Drop elaboration left behind a Drop for a type that does not need dropping"
+                    );
                 }
 
                 if dropped_place.is_indirect() {
@@ -87,6 +89,10 @@ impl Visitor<'tcx> for CheckLiveDrops<'mir, 'tcx> {
                     return;
                 }
 
+                // Drop elaboration is not precise enough to accept code like
+                // `src/test/ui/consts/control-flow/drop-pass.rs`; e.g., when an `Option<Vec<T>>` is
+                // initialized with `None` and never changed, it still emits drop glue.
+                // Hence we additionally check the qualifs here to allow more code to pass.
                 if self.qualifs.needs_drop(self.ccx, dropped_place.local, location) {
                     // Use the span where the dropped local was declared for the error.
                     let span = self.body.local_decls[dropped_place.local].source_info.span;