diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index c9b36d77e1a..cec833f2e56 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1425,6 +1425,7 @@ symbols! {
         pat_param,
         patchable_function_entry,
         path,
+        path_main_separator,
         path_to_pathbuf,
         pathbuf_as_path,
         pattern_complexity,
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 2ba3a9cdca2..aa9f63d915a 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -263,6 +263,7 @@ pub fn is_separator(c: char) -> bool {
 ///
 /// For example, `/` on Unix and `\` on Windows.
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "path_main_separator")]
 pub const MAIN_SEPARATOR: char = crate::sys::path::MAIN_SEP;
 
 /// The primary separator of path components for the current platform.
diff --git a/src/tools/clippy/clippy_lints/src/manual_main_separator_str.rs b/src/tools/clippy/clippy_lints/src/manual_main_separator_str.rs
index db491a8c8f6..5198d7838a2 100644
--- a/src/tools/clippy/clippy_lints/src/manual_main_separator_str.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_main_separator_str.rs
@@ -1,7 +1,7 @@
 use clippy_config::msrvs::{self, Msrv};
 use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::{is_trait_method, match_def_path, paths, peel_hir_expr_refs};
+use clippy_utils::{is_trait_method, peel_hir_expr_refs};
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Expr, ExprKind, Mutability, QPath};
@@ -56,7 +56,7 @@ impl LateLintPass<'_> for ManualMainSeparatorStr {
             && let Res::Def(DefKind::Const, receiver_def_id) = path.res
             && is_trait_method(cx, target, sym::ToString)
             && self.msrv.meets(msrvs::PATH_MAIN_SEPARATOR_STR)
-            && match_def_path(cx, receiver_def_id, &paths::PATH_MAIN_SEPARATOR)
+            && cx.tcx.is_diagnostic_item(sym::path_main_separator, receiver_def_id)
             && let ty::Ref(_, ty, Mutability::Not) = cx.typeck_results().expr_ty_adjusted(expr).kind()
             && ty.is_str()
         {
diff --git a/src/tools/clippy/clippy_utils/src/paths.rs b/src/tools/clippy/clippy_utils/src/paths.rs
index 0a36d9a6664..5e8157ac0c3 100644
--- a/src/tools/clippy/clippy_utils/src/paths.rs
+++ b/src/tools/clippy/clippy_utils/src/paths.rs
@@ -40,7 +40,6 @@ pub const OPEN_OPTIONS_NEW: [&str; 4] = ["std", "fs", "OpenOptions", "new"];
 pub const PARKING_LOT_MUTEX_GUARD: [&str; 3] = ["lock_api", "mutex", "MutexGuard"];
 pub const PARKING_LOT_RWLOCK_READ_GUARD: [&str; 3] = ["lock_api", "rwlock", "RwLockReadGuard"];
 pub const PARKING_LOT_RWLOCK_WRITE_GUARD: [&str; 3] = ["lock_api", "rwlock", "RwLockWriteGuard"];
-pub const PATH_MAIN_SEPARATOR: [&str; 3] = ["std", "path", "MAIN_SEPARATOR"];
 #[cfg_attr(not(unix), allow(clippy::invalid_paths))]
 pub const PERMISSIONS_FROM_MODE: [&str; 6] = ["std", "os", "unix", "fs", "PermissionsExt", "from_mode"];
 pub const PUSH_STR: [&str; 4] = ["alloc", "string", "String", "push_str"];