diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 9403908948082..d155e95078be2 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -192,6 +192,7 @@ symbols! {
         Capture,
         Cell,
         Center,
+        Child,
         Cleanup,
         Clone,
         CoercePointee,
@@ -336,6 +337,7 @@ symbols! {
         SliceIter,
         Some,
         SpanCtxt,
+        Stdin,
         String,
         StructuralPartialEq,
         SubdiagMessage,
@@ -599,6 +601,9 @@ symbols! {
         cfi,
         cfi_encoding,
         char,
+        char_is_ascii,
+        child_id,
+        child_kill,
         client,
         clippy,
         clobber_abi,
@@ -1468,6 +1473,7 @@ symbols! {
         panic_2015,
         panic_2021,
         panic_abort,
+        panic_any,
         panic_bounds_check,
         panic_cannot_unwind,
         panic_const_add_overflow,
@@ -1573,6 +1579,7 @@ symbols! {
         proc_macro_mod,
         proc_macro_non_items,
         proc_macro_path_invoc,
+        process_abort,
         process_exit,
         profiler_builtins,
         profiler_runtime,
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs
index ccfdbf0eb704d..34f5c3e94bcd5 100644
--- a/library/core/src/char/methods.rs
+++ b/library/core/src/char/methods.rs
@@ -1168,6 +1168,7 @@ impl char {
     #[must_use]
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[rustc_const_stable(feature = "const_char_is_ascii", since = "1.32.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "char_is_ascii")]
     #[inline]
     pub const fn is_ascii(&self) -> bool {
         *self as u32 <= 0x7F
diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs
index 318c350822168..661c422811abb 100644
--- a/library/std/src/io/stdio.rs
+++ b/library/std/src/io/stdio.rs
@@ -239,6 +239,7 @@ fn handle_ebadf_lazy<T>(r: io::Result<T>, default: impl FnOnce() -> T) -> io::Re
 /// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Stdin")]
 pub struct Stdin {
     inner: &'static Mutex<BufReader<StdinRaw>>,
 }
diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs
index 61801db072a0e..22776ae2bc4a7 100644
--- a/library/std/src/panic.rs
+++ b/library/std/src/panic.rs
@@ -255,6 +255,7 @@ pub use crate::panicking::{set_hook, take_hook};
 #[stable(feature = "panic_any", since = "1.51.0")]
 #[inline]
 #[track_caller]
+#[cfg_attr(not(test), rustc_diagnostic_item = "panic_any")]
 pub fn panic_any<M: 'static + Any + Send>(msg: M) -> ! {
     crate::panicking::begin_panic(msg);
 }
diff --git a/library/std/src/process.rs b/library/std/src/process.rs
index fd0fd1cb755e0..bdd4844b6511a 100644
--- a/library/std/src/process.rs
+++ b/library/std/src/process.rs
@@ -217,6 +217,7 @@ use crate::{fmt, fs, str};
 ///
 /// [`wait`]: Child::wait
 #[stable(feature = "process", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Child")]
 pub struct Child {
     pub(crate) handle: imp::Process,
 
@@ -2115,6 +2116,7 @@ impl Child {
     /// [`ErrorKind`]: io::ErrorKind
     /// [`InvalidInput`]: io::ErrorKind::InvalidInput
     #[stable(feature = "process", since = "1.0.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "child_kill")]
     pub fn kill(&mut self) -> io::Result<()> {
         self.handle.kill()
     }
@@ -2135,6 +2137,7 @@ impl Child {
     /// ```
     #[must_use]
     #[stable(feature = "process_id", since = "1.3.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "child_id")]
     pub fn id(&self) -> u32 {
         self.handle.id()
     }
@@ -2375,6 +2378,7 @@ pub fn exit(code: i32) -> ! {
 /// [panic hook]: crate::panic::set_hook
 #[stable(feature = "process_abort", since = "1.17.0")]
 #[cold]
+#[cfg_attr(not(test), rustc_diagnostic_item = "process_abort")]
 pub fn abort() -> ! {
     crate::sys::abort_internal();
 }