Auto merge of #108620 - Dylan-DPC:rollup-o5c4evy, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - #108143 (rustdoc: search by macro when query ends with `!`)
 - #108394 (Make `x doc --open` work on every book)
 - #108427 (Recover from for-else and while-else)
 - #108462 (Fix `VecDeque::append` capacity overflow for ZSTs)
 - #108568 (Make associated_item_def_ids for traits use an unstable option to also return associated types for RPITITs)
 - #108604 (Add regression test for #107280)
 - #108605 (Add regression test for #105821)

Failed merges:

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

40 files changed, 642 insertions, 72 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 27490a09a36..ccb07804b96 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1101,9 +1101,18 @@ fn should_encode_const(def_kind: DefKind) -> bool {
     }
 }
 
-// Return `false` to avoid encoding impl trait in trait, while we don't use the query.
-fn should_encode_fn_impl_trait_in_trait<'tcx>(_tcx: TyCtxt<'tcx>, _def_id: DefId) -> bool {
-    false
+// We only encode impl trait in trait when using `lower-impl-trait-in-trait-to-assoc-ty` unstable
+// option.
+fn should_encode_fn_impl_trait_in_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
+    if tcx.sess.opts.unstable_opts.lower_impl_trait_in_trait_to_assoc_ty
+        && let Some(assoc_item) = tcx.opt_associated_item(def_id)
+        && assoc_item.container == ty::AssocItemContainer::TraitContainer
+        && assoc_item.kind == ty::AssocKind::Fn
+    {
+        true
+    } else {
+        false
+    }
 }
 
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index ad119c4e073..c9da711e556 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -177,6 +177,7 @@ pub fn provide(providers: &mut Providers) {
         }
     };
     providers.opt_def_kind = |tcx, def_id| tcx.hir().opt_def_kind(def_id.expect_local());
+    providers.opt_rpitit_info = |_, _| None;
     providers.all_local_trait_impls = |tcx, ()| &tcx.resolutions(()).trait_impls;
     providers.expn_that_defined = |tcx, id| {
         let id = id.expect_local();
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index b07540cf58c..51feae3cf8a 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -90,6 +90,7 @@ rustc_queries! {
     /// Definitions that were generated with no HIR, would be feeded to return `None`.
     query opt_local_def_id_to_hir_id(key: LocalDefId) -> Option<hir::HirId>{
         desc { |tcx| "getting HIR ID of `{}`", tcx.def_path_str(key.to_def_id()) }
+        feedable
     }
 
     /// Gives access to the HIR node's parent for the HIR owner `key`.
@@ -166,6 +167,7 @@ rustc_queries! {
         }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     query collect_return_position_impl_trait_in_trait_tys(key: DefId)
@@ -222,6 +224,7 @@ rustc_queries! {
         arena_cache
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     /// Maps from the `DefId` of an item (trait/struct/enum/fn) to the
@@ -264,6 +267,7 @@ rustc_queries! {
         desc { |tcx| "finding item bounds for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     /// Elaborated version of the predicates from `explicit_item_bounds`.
@@ -588,6 +592,7 @@ rustc_queries! {
         desc { |tcx| "computing explicit predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     /// Returns the inferred outlives predicates (e.g., for `struct
@@ -596,6 +601,7 @@ rustc_queries! {
         desc { |tcx| "computing inferred outlives predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     /// Maps from the `DefId` of a trait to the list of
@@ -728,6 +734,7 @@ rustc_queries! {
         desc { |tcx| "computing associated item data for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
+        feedable
     }
 
     /// Collects the associated items defined on a trait or impl.
@@ -1142,6 +1149,15 @@ rustc_queries! {
         desc { |tcx| "looking up definition kind of `{}`", tcx.def_path_str(def_id) }
         cache_on_disk_if { def_id.is_local() }
         separate_provide_extern
+        feedable
+    }
+
+    /// The `opt_rpitit_info` query returns the pair of the def id of the function where the RPIT
+    /// is defined and the opaque def id if any.
+    query opt_rpitit_info(def_id: DefId) -> Option<ty::ImplTraitInTraitData> {
+        desc { |tcx| "opt_rpitit_info `{}`", tcx.def_path_str(def_id) }
+        cache_on_disk_if { def_id.is_local() }
+        feedable
     }
 
     /// Gets the span for the definition.
@@ -1157,6 +1173,7 @@ rustc_queries! {
         desc { |tcx| "looking up span for `{}`'s identifier", tcx.def_path_str(def_id) }
         cache_on_disk_if { def_id.is_local() }
         separate_provide_extern
+        feedable
     }
 
     query lookup_stability(def_id: DefId) -> Option<attr::Stability> {
@@ -1498,6 +1515,7 @@ rustc_queries! {
         desc { |tcx| "looking up whether `{}` is a default impl", tcx.def_path_str(def_id) }
         cache_on_disk_if { def_id.is_local() }
         separate_provide_extern
+        feedable
     }
 
     query check_well_formed(key: hir::OwnerId) -> () {
@@ -1695,6 +1713,7 @@ rustc_queries! {
     query visibility(def_id: DefId) -> ty::Visibility<DefId> {
         desc { |tcx| "computing visibility of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
+        feedable
     }
 
     query inhabited_predicate_adt(key: DefId) -> ty::inhabitedness::InhabitedPredicate<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 5084bc9cec6..5df01b8abc3 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -2071,6 +2071,12 @@ pub enum ImplOverlapKind {
     Issue33140,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+pub enum ImplTraitInTraitData {
+    Trait { fn_def_id: DefId, opaque_def_id: DefId },
+    Impl { fn_def_id: DefId },
+}
+
 impl<'tcx> TyCtxt<'tcx> {
     pub fn typeck_body(self, body: hir::BodyId) -> &'tcx TypeckResults<'tcx> {
         self.typeck(self.hir().body_owner_def_id(body))
diff --git a/compiler/rustc_parse/locales/en-US.ftl b/compiler/rustc_parse/locales/en-US.ftl
index 4ddeeed5b7e..e76e91fc1b1 100644
--- a/compiler/rustc_parse/locales/en-US.ftl
+++ b/compiler/rustc_parse/locales/en-US.ftl
@@ -151,6 +151,10 @@ parse_missing_in_in_for_loop = missing `in` in `for` loop
 parse_missing_expression_in_for_loop = missing expression to iterate on in `for` loop
     .suggestion = try adding an expression to the `for` loop
 
+parse_loop_else = `{$loop_kind}...else` loops are not supported
+    .note = consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    .loop_keyword = `else` is attached to this loop
+
 parse_missing_comma_after_match_arm = expected `,` following `match` arm
     .suggestion = missing a comma here to end this `match` arm
 
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index c746a870964..1662db36d10 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -452,6 +452,17 @@ pub(crate) struct MissingExpressionInForLoop {
 }
 
 #[derive(Diagnostic)]
+#[diag(parse_loop_else)]
+#[note]
+pub(crate) struct LoopElseNotSupported {
+    #[primary_span]
+    pub span: Span,
+    pub loop_kind: &'static str,
+    #[label(parse_loop_keyword)]
+    pub loop_kw: Span,
+}
+
+#[derive(Diagnostic)]
 #[diag(parse_missing_comma_after_match_arm)]
 pub(crate) struct MissingCommaAfterMatchArm {
     #[primary_span]
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 24d4c17f5d8..b2951e7a184 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -2503,9 +2503,27 @@ impl<'a> Parser<'a> {
         let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
 
         let kind = ExprKind::ForLoop(pat, expr, loop_block, opt_label);
+
+        self.recover_loop_else("for", lo)?;
+
         Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
     }
 
+    /// Recovers from an `else` clause after a loop (`for...else`, `while...else`)
+    fn recover_loop_else(&mut self, loop_kind: &'static str, loop_kw: Span) -> PResult<'a, ()> {
+        if self.token.is_keyword(kw::Else) && self.may_recover() {
+            let else_span = self.token.span;
+            self.bump();
+            let else_clause = self.parse_expr_else()?;
+            self.sess.emit_err(errors::LoopElseNotSupported {
+                span: else_span.to(else_clause.span),
+                loop_kind,
+                loop_kw,
+            });
+        }
+        Ok(())
+    }
+
     fn error_missing_in_for_loop(&mut self) {
         let (span, sub): (_, fn(_) -> _) = if self.token.is_ident_named(sym::of) {
             // Possibly using JS syntax (#75311).
@@ -2530,6 +2548,9 @@ impl<'a> Parser<'a> {
             err.span_label(cond.span, "this `while` condition successfully parsed");
             err
         })?;
+
+        self.recover_loop_else("while", lo)?;
+
         Ok(self.mk_expr_with_attrs(
             lo.to(self.prev_token.span),
             ExprKind::While(cond, body, opt_label),
@@ -2541,6 +2562,7 @@ impl<'a> Parser<'a> {
     fn parse_expr_loop(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
         let loop_span = self.prev_token.span;
         let (attrs, body) = self.parse_inner_attrs_and_block()?;
+        self.recover_loop_else("loop", lo)?;
         Ok(self.mk_expr_with_attrs(
             lo.to(self.prev_token.span),
             ExprKind::Loop(body, opt_label, loop_span),
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 4beac931632..b466a3fcdee 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1503,6 +1503,9 @@ options! {
         "what location details should be tracked when using caller_location, either \
         `none`, or a comma separated list of location details, for which \
         valid options are `file`, `line`, and `column` (default: `file,line,column`)"),
+    lower_impl_trait_in_trait_to_assoc_ty: bool = (false, parse_bool, [TRACKED],
+        "modify the lowering strategy for `impl Trait` in traits so that they are lowered to \
+        generic associated types"),
     ls: bool = (false, parse_bool, [UNTRACKED],
         "list the symbols defined by a library crate (default: no)"),
     macro_backtrace: bool = (false, parse_bool, [UNTRACKED],
diff --git a/compiler/rustc_ty_utils/src/assoc.rs b/compiler/rustc_ty_utils/src/assoc.rs
index d4866b5dbdd..efbbfe6c24b 100644
--- a/compiler/rustc_ty_utils/src/assoc.rs
+++ b/compiler/rustc_ty_utils/src/assoc.rs
@@ -4,7 +4,8 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::definitions::DefPathData;
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_middle::ty::{self, DefIdTree, TyCtxt};
+use rustc_middle::ty::{self, DefIdTree, ImplTraitInTraitData, InternalSubsts, TyCtxt};
+use rustc_span::symbol::kw;
 
 pub fn provide(providers: &mut ty::query::Providers) {
     *providers = ty::query::Providers {
@@ -21,9 +22,37 @@ pub fn provide(providers: &mut ty::query::Providers) {
 fn associated_item_def_ids(tcx: TyCtxt<'_>, def_id: DefId) -> &[DefId] {
     let item = tcx.hir().expect_item(def_id.expect_local());
     match item.kind {
-        hir::ItemKind::Trait(.., ref trait_item_refs) => tcx.arena.alloc_from_iter(
-            trait_item_refs.iter().map(|trait_item_ref| trait_item_ref.id.owner_id.to_def_id()),
-        ),
+        hir::ItemKind::Trait(.., ref trait_item_refs) => {
+            if tcx.sess.opts.unstable_opts.lower_impl_trait_in_trait_to_assoc_ty {
+                // We collect RPITITs for each trait method's return type and create a
+                // corresponding associated item using associated_items_for_impl_trait_in_trait
+                // query.
+                tcx.arena.alloc_from_iter(
+                    trait_item_refs
+                        .iter()
+                        .map(|trait_item_ref| trait_item_ref.id.owner_id.to_def_id())
+                        .chain(
+                            trait_item_refs
+                                .iter()
+                                .filter(|trait_item_ref| {
+                                    matches!(trait_item_ref.kind, hir::AssocItemKind::Fn { .. })
+                                })
+                                .flat_map(|trait_item_ref| {
+                                    let trait_fn_def_id =
+                                        trait_item_ref.id.owner_id.def_id.to_def_id();
+                                    tcx.associated_items_for_impl_trait_in_trait(trait_fn_def_id)
+                                })
+                                .map(|def_id| *def_id),
+                        ),
+                )
+            } else {
+                tcx.arena.alloc_from_iter(
+                    trait_item_refs
+                        .iter()
+                        .map(|trait_item_ref| trait_item_ref.id.owner_id.to_def_id()),
+                )
+            }
+        }
         hir::ItemKind::Impl(ref impl_) => tcx.arena.alloc_from_iter(
             impl_.items.iter().map(|impl_item_ref| impl_item_ref.id.owner_id.to_def_id()),
         ),
@@ -193,10 +222,65 @@ fn associated_item_for_impl_trait_in_trait(
     let span = tcx.def_span(opaque_ty_def_id);
     let trait_assoc_ty =
         tcx.at(span).create_def(trait_def_id.expect_local(), DefPathData::ImplTraitAssocTy);
-    trait_assoc_ty.def_id()
+
+    let local_def_id = trait_assoc_ty.def_id();
+    let def_id = local_def_id.to_def_id();
+
+    trait_assoc_ty.opt_def_kind(Some(DefKind::AssocTy));
+
+    // There's no HIR associated with this new synthesized `def_id`, so feed
+    // `opt_local_def_id_to_hir_id` with `None`.
+    trait_assoc_ty.opt_local_def_id_to_hir_id(None);
+
+    // Copy span of the opaque.
+    trait_assoc_ty.def_ident_span(Some(span));
+
+    // Add the def_id of the function and opaque that generated this synthesized associated type.
+    trait_assoc_ty.opt_rpitit_info(Some(ImplTraitInTraitData::Trait {
+        fn_def_id,
+        opaque_def_id: opaque_ty_def_id.to_def_id(),
+    }));
+
+    trait_assoc_ty.associated_item(ty::AssocItem {
+        name: kw::Empty,
+        kind: ty::AssocKind::Type,
+        def_id,
+        trait_item_def_id: None,
+        container: ty::TraitContainer,
+        fn_has_self_parameter: false,
+    });
+
+    // Copy visility of the containing function.
+    trait_assoc_ty.visibility(tcx.visibility(fn_def_id));
+
+    // Copy impl_defaultness of the containing function.
+    trait_assoc_ty.impl_defaultness(tcx.impl_defaultness(fn_def_id));
+
+    // Copy type_of of the opaque.
+    trait_assoc_ty.type_of(ty::EarlyBinder(tcx.mk_opaque(
+        opaque_ty_def_id.to_def_id(),
+        InternalSubsts::identity_for_item(tcx, opaque_ty_def_id.to_def_id()),
+    )));
+
+    // Copy generics_of of the opaque.
+    trait_assoc_ty.generics_of(tcx.generics_of(opaque_ty_def_id).clone());
+
+    // There are no predicates for the synthesized associated type.
+    trait_assoc_ty.explicit_predicates_of(ty::GenericPredicates {
+        parent: Some(trait_def_id),
+        predicates: &[],
+    });
+
+    // There are no inferred outlives for the synthesized associated type.
+    trait_assoc_ty.inferred_outlives_of(&[]);
+
+    // FIXME implement this.
+    trait_assoc_ty.explicit_item_bounds(&[]);
+
+    local_def_id
 }
 
-/// Given an `trait_assoc_def_id` that corresponds to a previously synthethized impl trait in trait
+/// Given an `trait_assoc_def_id` that corresponds to a previously synthesized impl trait in trait
 /// into an associated type and an `impl_def_id` corresponding to an impl block, create and return
 /// the corresponding associated item inside the impl block.
 fn impl_associated_item_for_impl_trait_in_trait(
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index d4a12509b1c..8317ac431a5 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -1924,7 +1924,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     #[stable(feature = "append", since = "1.4.0")]
     pub fn append(&mut self, other: &mut Self) {
         if T::IS_ZST {
-            self.len += other.len;
+            self.len = self.len.checked_add(other.len).expect("capacity overflow");
             other.len = 0;
             other.head = 0;
             return;
diff --git a/library/alloc/tests/vec_deque.rs b/library/alloc/tests/vec_deque.rs
index 0b8f5281b78..5a0b852e8d5 100644
--- a/library/alloc/tests/vec_deque.rs
+++ b/library/alloc/tests/vec_deque.rs
@@ -1046,6 +1046,20 @@ fn test_append_double_drop() {
 }
 
 #[test]
+#[should_panic]
+fn test_append_zst_capacity_overflow() {
+    let mut v = Vec::with_capacity(usize::MAX);
+    // note: using resize instead of set_len here would
+    //       be *extremely* slow in unoptimized builds.
+    // SAFETY: `v` has capacity `usize::MAX`, and no initialization
+    //         is needed for empty tuples.
+    unsafe { v.set_len(usize::MAX) };
+    let mut v = VecDeque::from(v);
+    let mut w = vec![()].into();
+    v.append(&mut w);
+}
+
+#[test]
 fn test_retain() {
     let mut buf = VecDeque::new();
     buf.extend(1..5);
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 7f8aa2573dd..cc80763ef44 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -62,6 +62,7 @@ macro_rules! book {
                     target: self.target,
                     name: INTERNER.intern_str($book_name),
                     src: INTERNER.intern_path(builder.src.join($path)),
+                    parent: Some(self),
                 })
             }
         }
@@ -119,18 +120,20 @@ impl Step for UnstableBook {
             target: self.target,
             name: INTERNER.intern_str("unstable-book"),
             src: INTERNER.intern_path(builder.md_doc_out(self.target).join("unstable-book")),
+            parent: Some(self),
         })
     }
 }
 
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
-struct RustbookSrc {
+struct RustbookSrc<P: Step> {
     target: TargetSelection,
     name: Interned<String>,
     src: Interned<PathBuf>,
+    parent: Option<P>,
 }
 
-impl Step for RustbookSrc {
+impl<P: Step> Step for RustbookSrc<P> {
     type Output = ();
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
@@ -152,13 +155,18 @@ impl Step for RustbookSrc {
         let index = out.join("index.html");
         let rustbook = builder.tool_exe(Tool::Rustbook);
         let mut rustbook_cmd = builder.tool_cmd(Tool::Rustbook);
-        if builder.config.dry_run() || up_to_date(&src, &index) && up_to_date(&rustbook, &index) {
-            return;
+
+        if !builder.config.dry_run() && !(up_to_date(&src, &index) || up_to_date(&rustbook, &index))
+        {
+            builder.info(&format!("Rustbook ({}) - {}", target, name));
+            let _ = fs::remove_dir_all(&out);
+
+            builder.run(rustbook_cmd.arg("build").arg(&src).arg("-d").arg(out));
         }
-        builder.info(&format!("Rustbook ({}) - {}", target, name));
-        let _ = fs::remove_dir_all(&out);
 
-        builder.run(rustbook_cmd.arg("build").arg(&src).arg("-d").arg(out));
+        if self.parent.is_some() {
+            builder.maybe_open_in_browser::<P>(index)
+        }
     }
 }
 
@@ -205,6 +213,7 @@ impl Step for TheBook {
             target,
             name: INTERNER.intern_str("book"),
             src: INTERNER.intern_path(builder.src.join(&relative_path)),
+            parent: Some(self),
         });
 
         // building older edition redirects
@@ -213,6 +222,9 @@ impl Step for TheBook {
                 target,
                 name: INTERNER.intern_string(format!("book/{}", edition)),
                 src: INTERNER.intern_path(builder.src.join(&relative_path).join(edition)),
+                // There should only be one book that is marked as the parent for each target, so
+                // treat the other editions as not having a parent.
+                parent: Option::<Self>::None,
             });
         }
 
@@ -228,10 +240,6 @@ impl Step for TheBook {
 
             invoke_rustdoc(builder, compiler, &shared_assets, target, path);
         }
-
-        let out = builder.doc_out(target);
-        let index = out.join("book").join("index.html");
-        builder.maybe_open_in_browser::<Self>(index);
     }
 }
 
@@ -1032,10 +1040,7 @@ impl Step for RustcBook {
             target: self.target,
             name: INTERNER.intern_str("rustc"),
             src: INTERNER.intern_path(out_base),
+            parent: Some(self),
         });
-
-        let out = builder.doc_out(self.target);
-        let index = out.join("rustc").join("index.html");
-        builder.maybe_open_in_browser::<Self>(index);
     }
 }
diff --git a/src/doc/rustdoc/src/how-to-read-rustdoc.md b/src/doc/rustdoc/src/how-to-read-rustdoc.md
index d666d54b315..28a004a9253 100644
--- a/src/doc/rustdoc/src/how-to-read-rustdoc.md
+++ b/src/doc/rustdoc/src/how-to-read-rustdoc.md
@@ -84,6 +84,9 @@ When typing in the search bar, you can prefix your search term with a type
 followed by a colon (such as `mod:`) to restrict the results to just that
 kind of item. (The available items are listed in the help popup.)
 
+Searching for `println!` will search for a macro named `println`, just like
+searching for `macro:println` does.
+
 ### Changing displayed theme
 
 You can change the displayed theme by opening the settings menu (the gear
diff --git a/src/librustdoc/html/static/js/search.js b/src/librustdoc/html/static/js/search.js
index b3fc889431b..6501d32531f 100644
--- a/src/librustdoc/html/static/js/search.js
+++ b/src/librustdoc/html/static/js/search.js
@@ -300,20 +300,21 @@ function initSearch(rawSearchIndex) {
      * @return {integer}
      */
     function getIdentEndPosition(parserState) {
+        const start = parserState.pos;
         let end = parserState.pos;
-        let foundExclamation = false;
+        let foundExclamation = -1;
         while (parserState.pos < parserState.length) {
             const c = parserState.userQuery[parserState.pos];
             if (!isIdentCharacter(c)) {
                 if (c === "!") {
-                    if (foundExclamation) {
+                    if (foundExclamation !== -1) {
                         throw new Error("Cannot have more than one `!` in an ident");
                     } else if (parserState.pos + 1 < parserState.length &&
                         isIdentCharacter(parserState.userQuery[parserState.pos + 1])
                     ) {
                         throw new Error("`!` can only be at the end of an ident");
                     }
-                    foundExclamation = true;
+                    foundExclamation = parserState.pos;
                 } else if (isErrorCharacter(c)) {
                     throw new Error(`Unexpected \`${c}\``);
                 } else if (
@@ -326,9 +327,18 @@ function initSearch(rawSearchIndex) {
                     if (!isPathStart(parserState)) {
                         break;
                     }
+                    if (foundExclamation !== -1) {
+                        if (start <= (end - 2)) {
+                            throw new Error("Cannot have associated items in macros");
+                        } else {
+                            // if start == end - 1, we got the never type
+                            // while the never type has no associated macros, we still
+                            // can parse a path like that
+                            foundExclamation = -1;
+                        }
+                    }
                     // Skip current ":".
                     parserState.pos += 1;
-                    foundExclamation = false;
                 } else {
                     throw new Error(`Unexpected \`${c}\``);
                 }
@@ -336,6 +346,16 @@ function initSearch(rawSearchIndex) {
             parserState.pos += 1;
             end = parserState.pos;
         }
+        // if start == end - 1, we got the never type
+        if (foundExclamation !== -1 && start <= (end - 2)) {
+            if (parserState.typeFilter === null) {
+                parserState.typeFilter = "macro";
+            } else if (parserState.typeFilter !== "macro") {
+                throw new Error("Invalid search type: macro `!` and " +
+                    `\`${parserState.typeFilter}\` both specified`);
+            }
+            end = foundExclamation;
+        }
         return end;
     }
 
@@ -589,8 +609,8 @@ function initSearch(rawSearchIndex) {
      *
      * The supported syntax by this parser is as follow:
      *
-     * ident = *(ALPHA / DIGIT / "_") [!]
-     * path = ident *(DOUBLE-COLON ident)
+     * ident = *(ALPHA / DIGIT / "_")
+     * path = ident *(DOUBLE-COLON ident) [!]
      * arg = path [generics]
      * arg-without-generic = path
      * type-sep = COMMA/WS *(COMMA/WS)
diff --git a/tests/rustdoc-js-std/parser-errors.js b/tests/rustdoc-js-std/parser-errors.js
index dc42031e05f..f82a2472063 100644
--- a/tests/rustdoc-js-std/parser-errors.js
+++ b/tests/rustdoc-js-std/parser-errors.js
@@ -37,6 +37,8 @@ const QUERY = [
     "mod : :",
     "a!a",
     "a!!",
+    "mod:a!",
+    "a!::a",
 ];
 
 const PARSED = [
@@ -382,4 +384,22 @@ const PARSED = [
         userQuery: "a!!",
         error: 'Cannot have more than one `!` in an ident',
     },
+    {
+        elems: [],
+        foundElems: 0,
+        original: "mod:a!",
+        returned: [],
+        typeFilter: -1,
+        userQuery: "mod:a!",
+        error: 'Invalid search type: macro `!` and `mod` both specified',
+    },
+    {
+        elems: [],
+        foundElems: 0,
+        original: "a!::a",
+        returned: [],
+        typeFilter: -1,
+        userQuery: "a!::a",
+        error: 'Cannot have associated items in macros',
+    },
 ];
diff --git a/tests/rustdoc-js-std/parser-filter.js b/tests/rustdoc-js-std/parser-filter.js
index e5a87a415ac..01f65b478f8 100644
--- a/tests/rustdoc-js-std/parser-filter.js
+++ b/tests/rustdoc-js-std/parser-filter.js
@@ -1,4 +1,4 @@
-const QUERY = ['fn:foo', 'enum : foo', 'macro<f>:foo'];
+const QUERY = ['fn:foo', 'enum : foo', 'macro<f>:foo', 'macro!', 'macro:mac!', 'a::mac!'];
 
 const PARSED = [
     {
@@ -40,4 +40,49 @@ const PARSED = [
         userQuery: "macro<f>:foo",
         error: "Unexpected `:`",
     },
+    {
+        elems: [{
+            name: "macro",
+            fullPath: ["macro"],
+            pathWithoutLast: [],
+            pathLast: "macro",
+            generics: [],
+        }],
+        foundElems: 1,
+        original: "macro!",
+        returned: [],
+        typeFilter: 14,
+        userQuery: "macro!",
+        error: null,
+    },
+    {
+        elems: [{
+            name: "mac",
+            fullPath: ["mac"],
+            pathWithoutLast: [],
+            pathLast: "mac",
+            generics: [],
+        }],
+        foundElems: 1,
+        original: "macro:mac!",
+        returned: [],
+        typeFilter: 14,
+        userQuery: "macro:mac!",
+        error: null,
+    },
+    {
+        elems: [{
+            name: "a::mac",
+            fullPath: ["a", "mac"],
+            pathWithoutLast: ["a"],
+            pathLast: "mac",
+            generics: [],
+        }],
+        foundElems: 1,
+        original: "a::mac!",
+        returned: [],
+        typeFilter: 14,
+        userQuery: "a::mac!",
+        error: null,
+    },
 ];
diff --git a/tests/rustdoc-js-std/parser-ident.js b/tests/rustdoc-js-std/parser-ident.js
index 4b5ab01ac76..6c17d00f16e 100644
--- a/tests/rustdoc-js-std/parser-ident.js
+++ b/tests/rustdoc-js-std/parser-ident.js
@@ -3,6 +3,7 @@ const QUERY = [
     "!",
     "a!",
     "a!::b",
+    "!::b",
     "a!::b!",
 ];
 
@@ -47,47 +48,50 @@ const PARSED = [
     },
     {
         elems: [{
-            name: "a!",
-            fullPath: ["a!"],
+            name: "a",
+            fullPath: ["a"],
             pathWithoutLast: [],
-            pathLast: "a!",
+            pathLast: "a",
             generics: [],
         }],
         foundElems: 1,
         original: "a!",
         returned: [],
-        typeFilter: -1,
+        typeFilter: 14,
         userQuery: "a!",
         error: null,
     },
     {
-        elems: [{
-            name: "a!::b",
-            fullPath: ["a!", "b"],
-            pathWithoutLast: ["a!"],
-            pathLast: "b",
-            generics: [],
-        }],
-        foundElems: 1,
+        elems: [],
+        foundElems: 0,
         original: "a!::b",
         returned: [],
         typeFilter: -1,
         userQuery: "a!::b",
-        error: null,
+        error: "Cannot have associated items in macros",
     },
     {
         elems: [{
-            name: "a!::b!",
-            fullPath: ["a!", "b!"],
-            pathWithoutLast: ["a!"],
-            pathLast: "b!",
+            name: "!::b",
+            fullPath: ["!", "b"],
+            pathWithoutLast: ["!"],
+            pathLast: "b",
             generics: [],
         }],
         foundElems: 1,
+        original: "!::b",
+        returned: [],
+        typeFilter: -1,
+        userQuery: "!::b",
+        error: null,
+    },
+    {
+        elems: [],
+        foundElems: 0,
         original: "a!::b!",
         returned: [],
         typeFilter: -1,
         userQuery: "a!::b!",
-        error: null,
+        error: "Cannot have associated items in macros",
     },
 ];
diff --git a/tests/rustdoc-js/macro-search.js b/tests/rustdoc-js/macro-search.js
new file mode 100644
index 00000000000..2b179ce146b
--- /dev/null
+++ b/tests/rustdoc-js/macro-search.js
@@ -0,0 +1,10 @@
+// exact-check
+
+const QUERY = 'abracadabra!';
+
+const EXPECTED = {
+    'others': [
+        { 'path': 'macro_search', 'name': 'abracadabra' },
+        { 'path': 'macro_search', 'name': 'abracadabra_b' },
+    ],
+};
diff --git a/tests/rustdoc-js/macro-search.rs b/tests/rustdoc-js/macro-search.rs
new file mode 100644
index 00000000000..dc397490cf5
--- /dev/null
+++ b/tests/rustdoc-js/macro-search.rs
@@ -0,0 +1,10 @@
+#[macro_export]
+macro_rules! abracadabra {
+    () => {}
+}
+#[macro_export]
+macro_rules! abracadabra_b {
+    () => {}
+}
+pub fn abracadabra() {}
+pub fn abracadabra_c() {}
diff --git a/tests/rustdoc-ui/z-help.stdout b/tests/rustdoc-ui/z-help.stdout
index 6aa9785f44e..79e6b94f1ac 100644
--- a/tests/rustdoc-ui/z-help.stdout
+++ b/tests/rustdoc-ui/z-help.stdout
@@ -87,6 +87,7 @@
     -Z                          llvm-plugins=val -- a list LLVM plugins to enable (space separated)
     -Z                       llvm-time-trace=val -- generate JSON tracing data file from LLVM data (default: no)
     -Z                       location-detail=val -- what location details should be tracked when using caller_location, either `none`, or a comma separated list of location details, for which valid options are `file`, `line`, and `column` (default: `file,line,column`)
+    -Z lower-impl-trait-in-trait-to-assoc-ty=val -- modify the lowering strategy for `impl Trait` in traits so that they are lowered to generic associated types
     -Z                                    ls=val -- list the symbols defined by a library crate (default: no)
     -Z                       macro-backtrace=val -- show macro backtraces (default: no)
     -Z           maximal-hir-to-mir-coverage=val -- save as much information as possible about the correspondence between MIR and HIR as source scopes (default: no)
diff --git a/tests/ui/async-await/issues/issue-107280.rs b/tests/ui/async-await/issues/issue-107280.rs
new file mode 100644
index 00000000000..85fce87403a
--- /dev/null
+++ b/tests/ui/async-await/issues/issue-107280.rs
@@ -0,0 +1,15 @@
+// edition:2021
+
+async fn foo() {
+    inner::<false>().await
+    //~^ ERROR: function takes 2 generic arguments but 1 generic argument was supplied
+    //~| ERROR: type inside `async fn` body must be known in this context
+    //~| ERROR: type inside `async fn` body must be known in this context
+    //~| ERROR: type inside `async fn` body must be known in this context
+    //~| ERROR: type inside `async fn` body must be known in this context
+    //~| ERROR: type inside `async fn` body must be known in this context
+}
+
+async fn inner<T, const PING: bool>() {}
+
+fn main() {}
diff --git a/tests/ui/async-await/issues/issue-107280.stderr b/tests/ui/async-await/issues/issue-107280.stderr
new file mode 100644
index 00000000000..dd3e10fcc18
--- /dev/null
+++ b/tests/ui/async-await/issues/issue-107280.stderr
@@ -0,0 +1,82 @@
+error[E0107]: function takes 2 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^   ----- supplied 1 generic argument
+   |     |
+   |     expected 2 generic arguments
+   |
+note: function defined here, with 2 generic parameters: `T`, `PING`
+  --> $DIR/issue-107280.rs:13:10
+   |
+LL | async fn inner<T, const PING: bool>() {}
+   |          ^^^^^ -  ----------------
+help: add missing generic argument
+   |
+LL |     inner::<false, PING>().await
+   |                  ++++++
+
+error[E0698]: type inside `async fn` body must be known in this context
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^^^^^^^^^^ cannot infer the value of const parameter `PING` declared on the function `inner`
+   |
+note: the type is part of the `async fn` body because of this `await`
+  --> $DIR/issue-107280.rs:4:21
+   |
+LL |     inner::<false>().await
+   |                     ^^^^^^
+
+error[E0698]: type inside `async fn` body must be known in this context
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^^^^^^^^^^ cannot infer the value of const parameter `PING` declared on the function `inner`
+   |
+note: the type is part of the `async fn` body because of this `await`
+  --> $DIR/issue-107280.rs:4:21
+   |
+LL |     inner::<false>().await
+   |                     ^^^^^^
+
+error[E0698]: type inside `async fn` body must be known in this context
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^^^^^^^^^^ cannot infer the value of const parameter `PING` declared on the function `inner`
+   |
+note: the type is part of the `async fn` body because of this `await`
+  --> $DIR/issue-107280.rs:4:21
+   |
+LL |     inner::<false>().await
+   |                     ^^^^^^
+
+error[E0698]: type inside `async fn` body must be known in this context
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^^^^^^^^^^ cannot infer the value of const parameter `PING` declared on the function `inner`
+   |
+note: the type is part of the `async fn` body because of this `await`
+  --> $DIR/issue-107280.rs:4:21
+   |
+LL |     inner::<false>().await
+   |                     ^^^^^^
+
+error[E0698]: type inside `async fn` body must be known in this context
+  --> $DIR/issue-107280.rs:4:5
+   |
+LL |     inner::<false>().await
+   |     ^^^^^^^^^^^^^^ cannot infer the value of const parameter `PING` declared on the function `inner`
+   |
+note: the type is part of the `async fn` body because of this `await`
+  --> $DIR/issue-107280.rs:4:21
+   |
+LL |     inner::<false>().await
+   |                     ^^^^^^
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0107, E0698.
+For more information about an error, try `rustc --explain E0107`.
diff --git a/tests/ui/const-generics/issues/issue-105821.rs b/tests/ui/const-generics/issues/issue-105821.rs
new file mode 100644
index 00000000000..cba2e22c460
--- /dev/null
+++ b/tests/ui/const-generics/issues/issue-105821.rs
@@ -0,0 +1,23 @@
+// check-pass
+
+#![allow(incomplete_features)]
+#![feature(adt_const_params, const_ptr_read, generic_const_exprs)]
+#![allow(dead_code)]
+
+const fn catone<const M: usize>(_a: &[u8; M]) -> [u8; M + 1]
+where
+    [(); M + 1]:,
+{
+    unimplemented!()
+}
+
+struct Catter<const A: &'static [u8]>;
+impl<const A: &'static [u8]> Catter<A>
+where
+    [(); A.len() + 1]:,
+{
+    const ZEROS: &'static [u8; A.len()] = &[0_u8; A.len()];
+    const R: &'static [u8] = &catone(Self::ZEROS);
+}
+
+fn main() {}
diff --git a/tests/ui/for/for-else-err.rs b/tests/ui/for/for-else-err.rs
new file mode 100644
index 00000000000..16252e980e4
--- /dev/null
+++ b/tests/ui/for/for-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    for _ in 0..1 {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `for...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    }
+}
diff --git a/tests/ui/for/for-else-err.stderr b/tests/ui/for/for-else-err.stderr
new file mode 100644
index 00000000000..b330d107647
--- /dev/null
+++ b/tests/ui/for/for-else-err.stderr
@@ -0,0 +1,17 @@
+error: `for...else` loops are not supported
+  --> $DIR/for-else-err.rs:4:7
+   |
+LL |       for _ in 0..1 {
+   |       --- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     }
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/for/for-else-let-else-err.rs b/tests/ui/for/for-else-let-else-err.rs
new file mode 100644
index 00000000000..c0b96f97294
--- /dev/null
+++ b/tests/ui/for/for-else-let-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let _ = for _ in 0..1 {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `for...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    };
+}
diff --git a/tests/ui/for/for-else-let-else-err.stderr b/tests/ui/for/for-else-let-else-err.stderr
new file mode 100644
index 00000000000..a2396a8fbb1
--- /dev/null
+++ b/tests/ui/for/for-else-let-else-err.stderr
@@ -0,0 +1,17 @@
+error: `for...else` loops are not supported
+  --> $DIR/for-else-let-else-err.rs:4:7
+   |
+LL |       let _ = for _ in 0..1 {
+   |               --- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     };
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/let-else/let-else-brace-before-else.fixed b/tests/ui/let-else/let-else-brace-before-else.fixed
index a75c770ddf2..2d85e3878cc 100644
--- a/tests/ui/let-else/let-else-brace-before-else.fixed
+++ b/tests/ui/let-else/let-else-brace-before-else.fixed
@@ -7,10 +7,6 @@ fn main() {
         //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
         return;
     };
-    let Some(1) = (loop { break Some(1) }) else {
-        //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
-        return;
-    };
     let 2 = 1 + (match 1 { n => n }) else {
         //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
         return;
diff --git a/tests/ui/let-else/let-else-brace-before-else.rs b/tests/ui/let-else/let-else-brace-before-else.rs
index 5603b946f38..5c3375b3f28 100644
--- a/tests/ui/let-else/let-else-brace-before-else.rs
+++ b/tests/ui/let-else/let-else-brace-before-else.rs
@@ -7,10 +7,6 @@ fn main() {
         //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
         return;
     };
-    let Some(1) = loop { break Some(1) } else {
-        //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
-        return;
-    };
     let 2 = 1 + match 1 { n => n } else {
         //~^ ERROR right curly brace `}` before `else` in a `let...else` statement not allowed
         return;
diff --git a/tests/ui/let-else/let-else-brace-before-else.stderr b/tests/ui/let-else/let-else-brace-before-else.stderr
index cb01e4c18a1..ee53213d8c2 100644
--- a/tests/ui/let-else/let-else-brace-before-else.stderr
+++ b/tests/ui/let-else/let-else-brace-before-else.stderr
@@ -10,18 +10,7 @@ LL |     let Some(1) = ({ Some(1) }) else {
    |                   +           +
 
 error: right curly brace `}` before `else` in a `let...else` statement not allowed
-  --> $DIR/let-else-brace-before-else.rs:10:40
-   |
-LL |     let Some(1) = loop { break Some(1) } else {
-   |                                        ^
-   |
-help: wrap the expression in parentheses
-   |
-LL |     let Some(1) = (loop { break Some(1) }) else {
-   |                   +                      +
-
-error: right curly brace `}` before `else` in a `let...else` statement not allowed
-  --> $DIR/let-else-brace-before-else.rs:14:34
+  --> $DIR/let-else-brace-before-else.rs:10:34
    |
 LL |     let 2 = 1 + match 1 { n => n } else {
    |                                  ^
@@ -32,7 +21,7 @@ LL |     let 2 = 1 + (match 1 { n => n }) else {
    |                 +                  +
 
 error: right curly brace `}` before `else` in a `let...else` statement not allowed
-  --> $DIR/let-else-brace-before-else.rs:18:40
+  --> $DIR/let-else-brace-before-else.rs:14:40
    |
 LL |     let Some(1) = unsafe { unsafe_fn() } else {
    |                                        ^
@@ -42,5 +31,5 @@ help: wrap the expression in parentheses
 LL |     let Some(1) = (unsafe { unsafe_fn() }) else {
    |                   +                      +
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
diff --git a/tests/ui/loops/loop-else-break-with-value.rs b/tests/ui/loops/loop-else-break-with-value.rs
new file mode 100644
index 00000000000..670d8a145c0
--- /dev/null
+++ b/tests/ui/loops/loop-else-break-with-value.rs
@@ -0,0 +1,10 @@
+fn main() {
+    let Some(1) = loop {
+        //~^ NOTE `else` is attached to this loop
+        break Some(1)
+    } else {
+        //~^ ERROR `loop...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+        return;
+    };
+}
diff --git a/tests/ui/loops/loop-else-break-with-value.stderr b/tests/ui/loops/loop-else-break-with-value.stderr
new file mode 100644
index 00000000000..972e2d341ec
--- /dev/null
+++ b/tests/ui/loops/loop-else-break-with-value.stderr
@@ -0,0 +1,18 @@
+error: `loop...else` loops are not supported
+  --> $DIR/loop-else-break-with-value.rs:5:7
+   |
+LL |       let Some(1) = loop {
+   |                     ---- `else` is attached to this loop
+...
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |         return;
+LL | |     };
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/loops/loop-else-err.rs b/tests/ui/loops/loop-else-err.rs
new file mode 100644
index 00000000000..202a09c255c
--- /dev/null
+++ b/tests/ui/loops/loop-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    loop {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `loop...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    }
+}
diff --git a/tests/ui/loops/loop-else-err.stderr b/tests/ui/loops/loop-else-err.stderr
new file mode 100644
index 00000000000..c2c5c84cded
--- /dev/null
+++ b/tests/ui/loops/loop-else-err.stderr
@@ -0,0 +1,17 @@
+error: `loop...else` loops are not supported
+  --> $DIR/loop-else-err.rs:4:7
+   |
+LL |       loop {
+   |       ---- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     }
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/loops/loop-else-let-else-err.rs b/tests/ui/loops/loop-else-let-else-err.rs
new file mode 100644
index 00000000000..e828ffef549
--- /dev/null
+++ b/tests/ui/loops/loop-else-let-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let _ = loop {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `loop...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    };
+}
diff --git a/tests/ui/loops/loop-else-let-else-err.stderr b/tests/ui/loops/loop-else-let-else-err.stderr
new file mode 100644
index 00000000000..a57c784ff6f
--- /dev/null
+++ b/tests/ui/loops/loop-else-let-else-err.stderr
@@ -0,0 +1,17 @@
+error: `loop...else` loops are not supported
+  --> $DIR/loop-else-let-else-err.rs:4:7
+   |
+LL |       let _ = loop {
+   |               ---- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     };
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/while/while-else-err.rs b/tests/ui/while/while-else-err.rs
new file mode 100644
index 00000000000..36b60fbd4be
--- /dev/null
+++ b/tests/ui/while/while-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    while false {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `while...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    };
+}
diff --git a/tests/ui/while/while-else-err.stderr b/tests/ui/while/while-else-err.stderr
new file mode 100644
index 00000000000..88f715d5666
--- /dev/null
+++ b/tests/ui/while/while-else-err.stderr
@@ -0,0 +1,17 @@
+error: `while...else` loops are not supported
+  --> $DIR/while-else-err.rs:4:7
+   |
+LL |       while false {
+   |       ----- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     };
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+
diff --git a/tests/ui/while/while-else-let-else-err.rs b/tests/ui/while/while-else-let-else-err.rs
new file mode 100644
index 00000000000..6d9909347c3
--- /dev/null
+++ b/tests/ui/while/while-else-let-else-err.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let _ = while false {
+        //~^ NOTE `else` is attached to this loop
+    } else {
+        //~^ ERROR `while...else` loops are not supported
+        //~| NOTE consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+    };
+}
diff --git a/tests/ui/while/while-else-let-else-err.stderr b/tests/ui/while/while-else-let-else-err.stderr
new file mode 100644
index 00000000000..431d37c007c
--- /dev/null
+++ b/tests/ui/while/while-else-let-else-err.stderr
@@ -0,0 +1,17 @@
+error: `while...else` loops are not supported
+  --> $DIR/while-else-let-else-err.rs:4:7
+   |
+LL |       let _ = while false {
+   |               ----- `else` is attached to this loop
+LL |
+LL |       } else {
+   |  _______^
+LL | |
+LL | |
+LL | |     };
+   | |_____^
+   |
+   = note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
+
+error: aborting due to previous error
+