diff --git a/compiler/rustc_error_codes/src/error_codes.rs b/compiler/rustc_error_codes/src/error_codes.rs
index c669f7fed272a..9ce74dd9b5a79 100644
--- a/compiler/rustc_error_codes/src/error_codes.rs
+++ b/compiler/rustc_error_codes/src/error_codes.rs
@@ -267,6 +267,7 @@ E0516: include_str!("./error_codes/E0516.md"),
 E0517: include_str!("./error_codes/E0517.md"),
 E0518: include_str!("./error_codes/E0518.md"),
 E0520: include_str!("./error_codes/E0520.md"),
+E0521: include_str!("./error_codes/E0521.md"),
 E0522: include_str!("./error_codes/E0522.md"),
 E0524: include_str!("./error_codes/E0524.md"),
 E0525: include_str!("./error_codes/E0525.md"),
@@ -597,7 +598,6 @@ E0780: include_str!("./error_codes/E0780.md"),
     E0514, // metadata version mismatch
     E0519, // local crate and dependency have same (crate-name, disambiguator)
     // two dependencies have same (crate-name, disambiguator) but different SVH
-    E0521, // borrowed data escapes outside of closure
     E0523,
 //  E0526, // shuffle indices are not constant
 //  E0540, // multiple rustc_deprecated attributes
diff --git a/compiler/rustc_error_codes/src/error_codes/E0521.md b/compiler/rustc_error_codes/src/error_codes/E0521.md
new file mode 100644
index 0000000000000..65dcac983acd5
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0521.md
@@ -0,0 +1,28 @@
+Borrowed data escapes outside of closure.
+
+Erroneous code example:
+
+```compile_fail,E0521
+let mut list: Vec<&str> = Vec::new();
+
+let _add = |el: &str| {
+    list.push(el); // error: `el` escapes the closure body here
+};
+```
+
+A type anotation of a closure parameter implies a new lifetime declaration.
+Consider to drop it, the compiler is reliably able to infer them.
+
+```
+let mut list: Vec<&str> = Vec::new();
+
+let _add = |el| {
+    list.push(el);
+};
+```
+
+See the [Closure type inference and annotation][closure-infere-annotation] and
+[Lifetime elision][lifetime-elision] sections of the Book for more details.
+
+[closure-infere-annotation]: https://doc.rust-lang.org/book/ch13-01-closures.html#closure-type-inference-and-annotation
+[lifetime-elision]: https://doc.rust-lang.org/reference/lifetime-elision.html
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 95ac2a31dd321..004c06029ffba 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -2083,18 +2083,11 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         output: Option<&'tcx hir::Ty<'tcx>>,
     ) {
         debug!("visit_fn_like_elision: enter");
-        let mut arg_elide = Elide::FreshLateAnon(Cell::new(0));
-        let arg_scope = Scope::Elision { elide: arg_elide.clone(), s: self.scope };
+        let arg_scope = Scope::Elision { elide: Elide::FreshLateAnon(Cell::new(0)), s: self.scope };
         self.with(arg_scope, |_, this| {
             for input in inputs {
                 this.visit_ty(input);
             }
-            match *this.scope {
-                Scope::Elision { ref elide, .. } => {
-                    arg_elide = elide.clone();
-                }
-                _ => bug!(),
-            }
         });
 
         let output = match output {
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 8a49fe0228c64..e509ec3f0213f 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1301,6 +1301,7 @@ crate enum TypeKind {
     Attr,
     Derive,
     TraitAlias,
+    Primitive,
 }
 
 crate trait GetDefId {
@@ -1403,6 +1404,16 @@ impl Type {
         matches!(self, Type::Generic(_))
     }
 
+    crate fn is_primitive(&self) -> bool {
+        match self {
+            Self::Primitive(_) => true,
+            Self::BorrowedRef { ref type_, .. } | Self::RawPointer(_, ref type_) => {
+                type_.is_primitive()
+            }
+            _ => false,
+        }
+    }
+
     crate fn projection(&self) -> Option<(&Type, DefId, Symbol)> {
         let (self_, trait_, name) = match self {
             QPath { self_type, trait_, name } => (self_type, trait_, name),
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index ce8e0cf981c38..e380d4672d055 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -171,11 +171,20 @@ crate fn get_real_types(
     cx: &DocContext<'_>,
     recurse: i32,
 ) -> FxHashSet<(Type, TypeKind)> {
+    fn insert(res: &mut FxHashSet<(Type, TypeKind)>, cx: &DocContext<'_>, ty: Type) {
+        if let Some(kind) = ty.def_id().map(|did| cx.tcx.def_kind(did).clean(cx)) {
+            res.insert((ty, kind));
+        } else if ty.is_primitive() {
+            // This is a primitive, let's store it as such.
+            res.insert((ty, TypeKind::Primitive));
+        }
+    }
     let mut res = FxHashSet::default();
     if recurse >= 10 {
         // FIXME: remove this whole recurse thing when the recursion bug is fixed
         return res;
     }
+
     if arg.is_full_generic() {
         let arg_s = Symbol::intern(&arg.print(&cx.cache).to_string());
         if let Some(where_pred) = generics.where_predicates.iter().find(|g| match g {
@@ -194,11 +203,7 @@ crate fn get_real_types(
                             if !adds.is_empty() {
                                 res.extend(adds);
                             } else if !ty.is_full_generic() {
-                                if let Some(kind) =
-                                    ty.def_id().map(|did| cx.tcx.def_kind(did).clean(cx))
-                                {
-                                    res.insert((ty, kind));
-                                }
+                                insert(&mut res, cx, ty);
                             }
                         }
                     }
@@ -212,17 +217,13 @@ crate fn get_real_types(
                     if !adds.is_empty() {
                         res.extend(adds);
                     } else if !ty.is_full_generic() {
-                        if let Some(kind) = ty.def_id().map(|did| cx.tcx.def_kind(did).clean(cx)) {
-                            res.insert((ty.clone(), kind));
-                        }
+                        insert(&mut res, cx, ty);
                     }
                 }
             }
         }
     } else {
-        if let Some(kind) = arg.def_id().map(|did| cx.tcx.def_kind(did).clean(cx)) {
-            res.insert((arg.clone(), kind));
-        }
+        insert(&mut res, cx, arg.clone());
         if let Some(gens) = arg.generics() {
             for gen in gens.iter() {
                 if gen.is_full_generic() {
@@ -230,8 +231,8 @@ crate fn get_real_types(
                     if !adds.is_empty() {
                         res.extend(adds);
                     }
-                } else if let Some(kind) = gen.def_id().map(|did| cx.tcx.def_kind(did).clean(cx)) {
-                    res.insert((gen.clone(), kind));
+                } else {
+                    insert(&mut res, cx, gen.clone());
                 }
             }
         }
diff --git a/src/librustdoc/formats/item_type.rs b/src/librustdoc/formats/item_type.rs
index f904de22f6ba4..7922a1ffa062e 100644
--- a/src/librustdoc/formats/item_type.rs
+++ b/src/librustdoc/formats/item_type.rs
@@ -119,6 +119,7 @@ impl From<clean::TypeKind> for ItemType {
             clean::TypeKind::Attr => ItemType::ProcAttribute,
             clean::TypeKind::Derive => ItemType::ProcDerive,
             clean::TypeKind::TraitAlias => ItemType::TraitAlias,
+            clean::TypeKind::Primitive => ItemType::Primitive,
         }
     }
 }
diff --git a/src/librustdoc/html/render/cache.rs b/src/librustdoc/html/render/cache.rs
index 5c02be14181ed..74a770b954853 100644
--- a/src/librustdoc/html/render/cache.rs
+++ b/src/librustdoc/html/render/cache.rs
@@ -78,7 +78,7 @@ crate fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
                 desc: item.doc_value().map_or_else(String::new, |s| short_markdown_summary(&s)),
                 parent: Some(did),
                 parent_idx: None,
-                search_type: get_index_search_type(&item, None),
+                search_type: get_index_search_type(&item, Some(cache)),
             });
             for alias in item.attrs.get_doc_aliases() {
                 cache
diff --git a/src/test/rustdoc-js/primitive.js b/src/test/rustdoc-js/primitive.js
new file mode 100644
index 0000000000000..918f7099918de
--- /dev/null
+++ b/src/test/rustdoc-js/primitive.js
@@ -0,0 +1,25 @@
+// exact-check
+
+const QUERY = [
+    "i32",
+    "str",
+    "TotoIsSomewhere",
+];
+
+const EXPECTED = [
+    {
+        'in_args': [
+            { 'path': 'primitive', 'name': 'foo' },
+        ],
+    },
+    {
+        'returned': [
+            { 'path': 'primitive', 'name': 'foo' },
+        ],
+    },
+    {
+        'others': [],
+        'in_args': [],
+        'returned': [],
+    },
+];
diff --git a/src/test/rustdoc-js/primitive.rs b/src/test/rustdoc-js/primitive.rs
new file mode 100644
index 0000000000000..2b30ccf15203e
--- /dev/null
+++ b/src/test/rustdoc-js/primitive.rs
@@ -0,0 +1,5 @@
+pub fn foo(i: i32) -> &'static str {
+    "hello"
+}
+
+pub fn foo2<TotoIsSomewhere>(i: &TotoIsSomewhere, j: TotoIsSomewhere) {}
diff --git a/src/test/ui/borrowck/issue-45983.stderr b/src/test/ui/borrowck/issue-45983.stderr
index efd414a2d44ff..feb098c598588 100644
--- a/src/test/ui/borrowck/issue-45983.stderr
+++ b/src/test/ui/borrowck/issue-45983.stderr
@@ -10,3 +10,4 @@ LL |     give_any(|y| x = Some(y));
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/borrowck/issue-7573.stderr b/src/test/ui/borrowck/issue-7573.stderr
index 815419db833e5..9d86286b8676c 100644
--- a/src/test/ui/borrowck/issue-7573.stderr
+++ b/src/test/ui/borrowck/issue-7573.stderr
@@ -12,3 +12,4 @@ LL |         lines_to_use.push(installed_id);
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/borrowck/regions-escape-bound-fn-2.stderr b/src/test/ui/borrowck/regions-escape-bound-fn-2.stderr
index 1dc60bb155452..14393bc8eeede 100644
--- a/src/test/ui/borrowck/regions-escape-bound-fn-2.stderr
+++ b/src/test/ui/borrowck/regions-escape-bound-fn-2.stderr
@@ -10,3 +10,4 @@ LL |     with_int(|y| x = Some(y));
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/borrowck/regions-escape-bound-fn.stderr b/src/test/ui/borrowck/regions-escape-bound-fn.stderr
index 5c548ec2876a3..a23fdacdee641 100644
--- a/src/test/ui/borrowck/regions-escape-bound-fn.stderr
+++ b/src/test/ui/borrowck/regions-escape-bound-fn.stderr
@@ -10,3 +10,4 @@ LL |     with_int(|y| x = Some(y));
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/borrowck/regions-escape-unboxed-closure.stderr b/src/test/ui/borrowck/regions-escape-unboxed-closure.stderr
index f2a49e70d2716..153f77c8913ac 100644
--- a/src/test/ui/borrowck/regions-escape-unboxed-closure.stderr
+++ b/src/test/ui/borrowck/regions-escape-unboxed-closure.stderr
@@ -10,3 +10,4 @@ LL |     with_int(&mut |y| x = Some(y));
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/fat-ptr-cast-rpass.rs b/src/test/ui/cast/fat-ptr-cast-rpass.rs
similarity index 100%
rename from src/test/ui/fat-ptr-cast-rpass.rs
rename to src/test/ui/cast/fat-ptr-cast-rpass.rs
diff --git a/src/test/ui/fat-ptr-cast.rs b/src/test/ui/cast/fat-ptr-cast.rs
similarity index 100%
rename from src/test/ui/fat-ptr-cast.rs
rename to src/test/ui/cast/fat-ptr-cast.rs
diff --git a/src/test/ui/fat-ptr-cast.stderr b/src/test/ui/cast/fat-ptr-cast.stderr
similarity index 100%
rename from src/test/ui/fat-ptr-cast.stderr
rename to src/test/ui/cast/fat-ptr-cast.stderr
diff --git a/src/test/ui/issues/issue-17444.rs b/src/test/ui/cast/issue-17444.rs
similarity index 100%
rename from src/test/ui/issues/issue-17444.rs
rename to src/test/ui/cast/issue-17444.rs
diff --git a/src/test/ui/issues/issue-17444.stderr b/src/test/ui/cast/issue-17444.stderr
similarity index 100%
rename from src/test/ui/issues/issue-17444.stderr
rename to src/test/ui/cast/issue-17444.stderr
diff --git a/src/test/ui/cast/unsupported-cast.rs b/src/test/ui/cast/unsupported-cast.rs
new file mode 100644
index 0000000000000..1384ecc6ef251
--- /dev/null
+++ b/src/test/ui/cast/unsupported-cast.rs
@@ -0,0 +1,5 @@
+struct A;
+
+fn main() {
+  println!("{:?}", 1.0 as *const A); //~ERROR  casting `f64` as `*const A` is invalid
+}
diff --git a/src/test/ui/unsupported-cast.stderr b/src/test/ui/cast/unsupported-cast.stderr
similarity index 65%
rename from src/test/ui/unsupported-cast.stderr
rename to src/test/ui/cast/unsupported-cast.stderr
index 63e7713d2f4e7..56a375a1d942a 100644
--- a/src/test/ui/unsupported-cast.stderr
+++ b/src/test/ui/cast/unsupported-cast.stderr
@@ -1,7 +1,7 @@
 error[E0606]: casting `f64` as `*const A` is invalid
-  --> $DIR/unsupported-cast.rs:6:20
+  --> $DIR/unsupported-cast.rs:4:20
    |
-LL |   println!("{:?}", 1.0 as *const A); // Can't cast float to foreign.
+LL |   println!("{:?}", 1.0 as *const A);
    |                    ^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
diff --git a/src/test/ui/closures/closure-expected-type/expect-region-supply-region.stderr b/src/test/ui/closures/closure-expected-type/expect-region-supply-region.stderr
index 213071abfffc3..0d97fa7e23014 100644
--- a/src/test/ui/closures/closure-expected-type/expect-region-supply-region.stderr
+++ b/src/test/ui/closures/closure-expected-type/expect-region-supply-region.stderr
@@ -20,3 +20,4 @@ LL |         f = Some(x);
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr b/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
index 9986220218e28..5fc8100409822 100644
--- a/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
+++ b/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
@@ -12,3 +12,4 @@ LL |         a = &b;
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index 0115f5412f21d..0932f9415480c 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -83,4 +83,5 @@ LL | }
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0597`.
+Some errors have detailed explanations: E0521, E0597.
+For more information about an error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
index e55d033d2c763..bf6e2a922ed08 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
@@ -51,3 +51,4 @@ LL | |     });
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
index ac4a4579c9cd2..a3d993848cbaa 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
@@ -51,3 +51,4 @@ LL | |     });
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/outlives-suggestion-simple.stderr b/src/test/ui/nll/outlives-suggestion-simple.stderr
index 6300ea66511fb..bfe98a71a99b1 100644
--- a/src/test/ui/nll/outlives-suggestion-simple.stderr
+++ b/src/test/ui/nll/outlives-suggestion-simple.stderr
@@ -106,3 +106,4 @@ LL |         Bar2::new(&self)
 
 error: aborting due to 9 previous errors
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/nll/user-annotations/closure-substs.stderr b/src/test/ui/nll/user-annotations/closure-substs.stderr
index e3e294106d168..37e751aeb67b7 100644
--- a/src/test/ui/nll/user-annotations/closure-substs.stderr
+++ b/src/test/ui/nll/user-annotations/closure-substs.stderr
@@ -38,3 +38,4 @@ LL |         b(x);
 
 error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/regions/issue-78262.nll.stderr b/src/test/ui/regions/issue-78262.nll.stderr
index 4607dbad4220b..fafff35e4155f 100644
--- a/src/test/ui/regions/issue-78262.nll.stderr
+++ b/src/test/ui/regions/issue-78262.nll.stderr
@@ -8,3 +8,4 @@ LL |     let f = |x: &dyn TT| x.func();
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/unsupported-cast.rs b/src/test/ui/unsupported-cast.rs
deleted file mode 100644
index cb6a57a4d39d5..0000000000000
--- a/src/test/ui/unsupported-cast.rs
+++ /dev/null
@@ -1,7 +0,0 @@
-// error-pattern:casting
-
-struct A;
-
-fn main() {
-  println!("{:?}", 1.0 as *const A); // Can't cast float to foreign.
-}
diff --git a/src/tools/rustdoc-js/tester.js b/src/tools/rustdoc-js/tester.js
index 3f6bd60397526..c21277de33513 100644
--- a/src/tools/rustdoc-js/tester.js
+++ b/src/tools/rustdoc-js/tester.js
@@ -203,6 +203,10 @@ function betterLookingDiff(entry, data) {
         if (!entry.hasOwnProperty(key)) {
             continue;
         }
+        if (!data || !data.hasOwnProperty(key)) {
+            output += '-' + spaces + contentToDiffLine(key, entry[key]) + '\n';
+            continue;
+        }
         let value = data[key];
         if (value !== entry[key]) {
             output += '-' + spaces + contentToDiffLine(key, entry[key]) + '\n';