diff --git a/env/rust.scm b/env/rust.scm
index b6325d7..73dd134 100644
--- a/env/rust.scm
+++ b/env/rust.scm
@@ -171,11 +171,16 @@ function."
                    (throw 'file-doesnt-exist))))))))
 
   (let* ((target (string-append (@@ (env) %env-directory) "/" target-name))
-         (mnt (mount-environment env #:tag tag #:target target))
+         ;; TODO should actually detect if overlay is mounted not that the
+         ;; directory exists.
+         (mnt (if (file-exists? target)
+                  target
+                  (overlay-mount-merged
+                   (mount-environment env #:tag tag #:target target))))
          (mappings (append (map (remap #f) expose)
                            (map (remap #t) share))))
     (exec-in-rustup-environment '("./.cargo/bin/rust-analyzer")
-                                #:home (overlay-mount-merged mnt)
+                                #:home mnt
                                 #:mappings mappings)
     (sync)
     (system* "umount" target)