diff --git a/compiler/rustc_interface/src/callbacks.rs b/compiler/rustc_interface/src/callbacks.rs
index a18e2d1d638..76442de69d3 100644
--- a/compiler/rustc_interface/src/callbacks.rs
+++ b/compiler/rustc_interface/src/callbacks.rs
@@ -24,7 +24,7 @@ fn track_span_parent(def_id: rustc_span::def_id::LocalDefId) {
 }
 
 /// This is a callback from `rustc_ast` as it cannot access the implicit state
-/// in `rustc_middle` otherwise. It is used to when diagnostic messages are
+/// in `rustc_middle` otherwise. It is used when diagnostic messages are
 /// emitted and stores them in the current query, if there is one.
 fn track_diagnostic(diagnostic: &Diagnostic) {
     tls::with_context_opt(|icx| {