diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 1c37a6b2aca18..1137a83bc77da 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -169,10 +169,14 @@ symbols! {
         Option,
         Ord,
         Ordering,
+        OsStr,
+        OsString,
         Output,
         Param,
         PartialEq,
         PartialOrd,
+        Path,
+        PathBuf,
         Pending,
         Pin,
         Poll,
@@ -198,6 +202,8 @@ symbols! {
         StructuralPartialEq,
         Sync,
         Target,
+        ToOwned,
+        ToString,
         Try,
         Ty,
         TyCtxt,
diff --git a/library/alloc/src/borrow.rs b/library/alloc/src/borrow.rs
index adf996fc78275..bdb2d67347e43 100644
--- a/library/alloc/src/borrow.rs
+++ b/library/alloc/src/borrow.rs
@@ -31,6 +31,7 @@ where
 /// implementing the `Clone` trait. But `Clone` works only for going from `&T`
 /// to `T`. The `ToOwned` trait generalizes `Clone` to construct owned data
 /// from any borrow of a given type.
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToOwned")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait ToOwned {
     /// The resulting type after obtaining ownership.
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs
index cb015b949305c..839f742f1afa7 100644
--- a/library/alloc/src/slice.rs
+++ b/library/alloc/src/slice.rs
@@ -220,6 +220,7 @@ mod hack {
 }
 
 #[lang = "slice_alloc"]
+#[cfg_attr(not(test), rustc_diagnostic_item = "slice")]
 #[cfg(not(test))]
 impl<T> [T] {
     /// Sorts the slice.
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 3218b3535c970..00fd1c2908b82 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2174,6 +2174,7 @@ impl FromStr for String {
 /// implementation for free.
 ///
 /// [`Display`]: fmt::Display
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToString")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait ToString {
     /// Converts the given value to a `String`.
diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index c9c8f68cd9cce..13c8022820bc3 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -71,6 +71,7 @@ use crate::sys_common::{AsInner, FromInner, IntoInner};
 /// [`CStr`]: crate::ffi::CStr
 /// [conversions]: super#conversions
 #[derive(Clone)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "OsString")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct OsString {
     inner: Buf,
@@ -89,6 +90,7 @@ pub struct OsString {
 ///
 /// [`&str`]: str
 /// [conversions]: super#conversions
+#[cfg_attr(not(test), rustc_diagnostic_item = "OsStr")]
 #[stable(feature = "rust1", since = "1.0.0")]
 // FIXME:
 // `OsStr::from_inner` current implementation relies
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 1889e54933867..afb28518b727d 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1066,6 +1066,7 @@ impl FusedIterator for Ancestors<'_> {}
 ///
 /// Which method works best depends on what kind of situation you're in.
 #[derive(Clone)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "PathBuf")]
 #[stable(feature = "rust1", since = "1.0.0")]
 // FIXME:
 // `PathBuf::as_mut_vec` current implementation relies
@@ -1719,6 +1720,7 @@ impl AsRef<OsStr> for PathBuf {
 /// let extension = path.extension();
 /// assert_eq!(extension, Some(OsStr::new("txt")));
 /// ```
+#[cfg_attr(not(test), rustc_diagnostic_item = "Path")]
 #[stable(feature = "rust1", since = "1.0.0")]
 // FIXME:
 // `Path::new` current implementation relies