Fix crash on lambdas with docstrings

Spotted when debugging #278.

2 files changed, 8 insertions, 1 deletions

diff --git a/helpful.el b/helpful.el
index 3e064d7..b54914f 100644
--- a/helpful.el
+++ b/helpful.el
@@ -2257,7 +2257,7 @@ state of the current symbol."
           (insert (helpful--format-docstring docstring)))
         (when version-info
           (insert "\n\n" (s-word-wrap 70 version-info)))
-        (when (helpful--in-manual-p helpful--sym)
+        (when (and (symbolp helpful--sym) (helpful--in-manual-p helpful--sym))
           (insert "\n\n")
           (insert (helpful--make-manual-button helpful--sym)))))
 
diff --git a/test/helpful-unit-test.el b/test/helpful-unit-test.el
index 510396c..0cfef04 100644
--- a/test/helpful-unit-test.el
+++ b/test/helpful-unit-test.el
@@ -566,6 +566,13 @@ associated a lambda with a keybinding."
     (with-current-buffer buf
       (helpful-update))))
 
+(ert-deftest helpful--unnamed-func-with-docstring ()
+  (let* ((fun (lambda (x) "Foo" x))
+         (buf (helpful--buffer fun t)))
+    ;; Don't crash when we show the buffer.
+    (with-current-buffer buf
+      (helpful-update))))
+
 (ert-deftest helpful--unnamed-compiled-func ()
   "Ensure we handle unnamed byte-compiled functions.