diff --git a/src/imports.rs b/src/imports.rs
index dd506000a69..a85889884ca 100644
--- a/src/imports.rs
+++ b/src/imports.rs
@@ -451,11 +451,10 @@ impl UseTree {
         // Normalise foo::self as bar -> foo as bar.
         if let UseSegment::Slf(_) = last {
             match self.path.last() {
-                None => {}
                 Some(UseSegment::Ident(_, None)) => {
                     aliased_self = true;
                 }
-                _ => unreachable!(),
+                _ => {}
             }
         }
 
diff --git a/tests/target/issue-3645.rs b/tests/target/issue-3645.rs
new file mode 100644
index 00000000000..14bf96e6383
--- /dev/null
+++ b/tests/target/issue-3645.rs
@@ -0,0 +1,3 @@
+mod x {
+    use super::self as x;
+}