diff --git a/crates/diagnostics/src/diagnostics.rs b/crates/diagnostics/src/diagnostics.rs
index 4d8162972326eec7fbcf8361ba782e48de03e4f1..4b8c943dd098fd2589d0c2a58408f57a27650713 100644
--- a/crates/diagnostics/src/diagnostics.rs
+++ b/crates/diagnostics/src/diagnostics.rs
@@ -867,10 +867,12 @@ fn compare_diagnostics(
     snapshot: &language::BufferSnapshot,
 ) -> Ordering {
     use language::ToOffset;
-    // The old diagnostics may point to a previously open Buffer for this file.
-    if !old.range.start.is_valid(snapshot) {
+
+    // The diagnostics may point to a previously open Buffer for this file.
+    if !old.range.start.is_valid(snapshot) || !new.range.start.is_valid(snapshot) {
         return Ordering::Greater;
     }
+
     old.range
         .start
         .to_offset(snapshot)