Auto merge of #90883 - matthiaskrgr:rollup-iu9k5pe, r=matthiaskrgr

Rollup of 3 pull requests

Successful merges:

 - #90771 (Fix trait object error code)
 - #90840 (relate lifetime in `TypeOutlives` bounds on drop impls)
 - #90853 (rustdoc: Use an empty Vec instead of Option<Vec>)

Failed merges:

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

7 files changed, 46 insertions, 18 deletions

diff --git a/compiler/rustc_typeck/src/check/dropck.rs b/compiler/rustc_typeck/src/check/dropck.rs
index bfa0d92ab47..4b4d29307ff 100644
--- a/compiler/rustc_typeck/src/check/dropck.rs
+++ b/compiler/rustc_typeck/src/check/dropck.rs
@@ -240,8 +240,12 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
                     ty::PredicateKind::ConstEvaluatable(a),
                     ty::PredicateKind::ConstEvaluatable(b),
                 ) => tcx.try_unify_abstract_consts((a, b)),
-                (ty::PredicateKind::TypeOutlives(a), ty::PredicateKind::TypeOutlives(b)) => {
-                    relator.relate(predicate.rebind(a.0), p.rebind(b.0)).is_ok()
+                (
+                    ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_a, lt_a)),
+                    ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(ty_b, lt_b)),
+                ) => {
+                    relator.relate(predicate.rebind(ty_a), p.rebind(ty_b)).is_ok()
+                        && relator.relate(predicate.rebind(lt_a), p.rebind(lt_b)).is_ok()
                 }
                 _ => predicate == p,
             }
diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
index 93b2a595259..aae59eee991 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
@@ -952,7 +952,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let mut err = rustc_errors::struct_span_err!(
                         self.sess(),
                         self_ty.span,
-                        E0783,
+                        E0782,
                         "{}",
                         msg,
                     );
diff --git a/src/librustdoc/html/render/cache.rs b/src/librustdoc/html/render/cache.rs
index b52369773fe..9164916af09 100644
--- a/src/librustdoc/html/render/cache.rs
+++ b/src/librustdoc/html/render/cache.rs
@@ -205,7 +205,6 @@ crate fn get_index_search_type<'tcx>(
 
     inputs.retain(|a| a.ty.name.is_some());
     output.retain(|a| a.ty.name.is_some());
-    let output = if output.is_empty() { None } else { Some(output) };
 
     Some(IndexItemFunctionType { inputs, output })
 }
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index e7904aeedd4..dd592de41bd 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -117,7 +117,7 @@ crate struct RenderType {
 #[derive(Debug)]
 crate struct IndexItemFunctionType {
     inputs: Vec<TypeWithKind>,
-    output: Option<Vec<TypeWithKind>>,
+    output: Vec<TypeWithKind>,
 }
 
 impl Serialize for IndexItemFunctionType {
@@ -126,21 +126,16 @@ impl Serialize for IndexItemFunctionType {
         S: Serializer,
     {
         // If we couldn't figure out a type, just write `null`.
-        let mut iter = self.inputs.iter();
-        if match self.output {
-            Some(ref output) => iter.chain(output.iter()).any(|i| i.ty.name.is_none()),
-            None => iter.any(|i| i.ty.name.is_none()),
-        } {
+        let has_missing = self.inputs.iter().chain(self.output.iter()).any(|i| i.ty.name.is_none());
+        if has_missing {
             serializer.serialize_none()
         } else {
             let mut seq = serializer.serialize_seq(None)?;
             seq.serialize_element(&self.inputs)?;
-            if let Some(output) = &self.output {
-                if output.len() > 1 {
-                    seq.serialize_element(&output)?;
-                } else {
-                    seq.serialize_element(&output[0])?;
-                }
+            match self.output.as_slice() {
+                [] => {}
+                [one] => seq.serialize_element(one)?,
+                all => seq.serialize_element(all)?,
             }
             seq.end()
         }
diff --git a/src/test/ui/dropck/relate_lt_in_type_outlives_bound.rs b/src/test/ui/dropck/relate_lt_in_type_outlives_bound.rs
new file mode 100644
index 00000000000..42530d31730
--- /dev/null
+++ b/src/test/ui/dropck/relate_lt_in_type_outlives_bound.rs
@@ -0,0 +1,13 @@
+struct Wrapper<'a, T>(&'a T)
+where
+    T: 'a;
+
+impl<'a, T> Drop for Wrapper<'a, T>
+where
+    T: 'static,
+    //~^ error: `Drop` impl requires `T: 'static` but the struct it is implemented for does not
+{
+    fn drop(&mut self) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/dropck/relate_lt_in_type_outlives_bound.stderr b/src/test/ui/dropck/relate_lt_in_type_outlives_bound.stderr
new file mode 100644
index 00000000000..5176684e153
--- /dev/null
+++ b/src/test/ui/dropck/relate_lt_in_type_outlives_bound.stderr
@@ -0,0 +1,17 @@
+error[E0367]: `Drop` impl requires `T: 'static` but the struct it is implemented for does not
+  --> $DIR/relate_lt_in_type_outlives_bound.rs:7:8
+   |
+LL |     T: 'static,
+   |        ^^^^^^^
+   |
+note: the implementor must specify the same requirement
+  --> $DIR/relate_lt_in_type_outlives_bound.rs:1:1
+   |
+LL | / struct Wrapper<'a, T>(&'a T)
+LL | | where
+LL | |     T: 'a;
+   | |__________^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0367`.
diff --git a/src/test/ui/editions/dyn-trait-sugg-2021.stderr b/src/test/ui/editions/dyn-trait-sugg-2021.stderr
index f6e9fa96a15..a7119b073ab 100644
--- a/src/test/ui/editions/dyn-trait-sugg-2021.stderr
+++ b/src/test/ui/editions/dyn-trait-sugg-2021.stderr
@@ -1,4 +1,4 @@
-error[E0783]: trait objects without an explicit `dyn` are deprecated
+error[E0782]: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-trait-sugg-2021.rs:10:5
    |
 LL |     Foo::hi(123);
@@ -6,4 +6,4 @@ LL |     Foo::hi(123);
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0783`.
+For more information about this error, try `rustc --explain E0782`.