From d480a7d077c321df0055c5d7179ef14b0c4f6e67 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <me@lukaswirth.dev>
Date: Sun, 7 Dec 2025 09:56:57 +0100
Subject: [PATCH] internal: Make `MacroCallId` a tracked struct instead of an
 interned

---
 crates/hir-expand/src/db.rs  |  2 +-
 crates/hir-expand/src/lib.rs | 24 ++++++++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/crates/hir-expand/src/db.rs b/crates/hir-expand/src/db.rs
index 5c517e671be4..12773c74a87d 100644
--- a/crates/hir-expand/src/db.rs
+++ b/crates/hir-expand/src/db.rs
@@ -697,7 +697,7 @@ fn check_tt_count(tt: &tt::TopSubtree) -> Result<(), ExpandResult<()>> {
 }
 
 fn intern_macro_call(db: &dyn ExpandDatabase, macro_call: MacroCallLoc) -> MacroCallId {
-    MacroCallId::new(db, macro_call)
+    unsafe { crate::MacroCallIdLt::new(db, macro_call).to_static() }
 }
 
 fn lookup_intern_macro_call(db: &dyn ExpandDatabase, macro_call: MacroCallId) -> MacroCallLoc {
diff --git a/crates/hir-expand/src/lib.rs b/crates/hir-expand/src/lib.rs
index c92e41f5070c..28d23e99de4e 100644
--- a/crates/hir-expand/src/lib.rs
+++ b/crates/hir-expand/src/lib.rs
@@ -1077,11 +1077,31 @@ impl ExpandTo {
 
 intern::impl_internable!(ModPath);
 
-#[salsa_macros::interned(no_lifetime, debug, revisions = usize::MAX)]
+#[salsa_macros::tracked(debug)]
+#[derive(PartialOrd, Ord)]
 #[doc(alias = "MacroFileId")]
-pub struct MacroCallId {
+pub struct MacroCallIdLt<'id> {
     pub loc: MacroCallLoc,
 }
+pub type MacroCallId = MacroCallIdLt<'static>;
+
+impl MacroCallIdLt<'_> {
+    /// # Safety
+    ///
+    /// The caller must ensure that the `MacroCallId` is not leaked outside of query computations.
+    pub unsafe fn to_static(self) -> MacroCallId {
+        unsafe { std::mem::transmute(self) }
+    }
+}
+
+impl MacroCallId {
+    /// # Safety
+    ///
+    /// The caller must ensure that the `MacroCallId` comes from the given database.
+    pub unsafe fn to_db<'db>(self, _db: &'db dyn ExpandDatabase) -> MacroCallIdLt<'db> {
+        unsafe { std::mem::transmute(self) }
+    }
+}
 
 impl From<span::MacroCallId> for MacroCallId {
     #[inline]