2 files changed, 25 insertions, 0 deletions

diff --git a/test/src/buffer-tests.el b/test/src/buffer-tests.el
index 793dddd8bd4..87406740a78 100644
--- a/test/src/buffer-tests.el
+++ b/test/src/buffer-tests.el
@@ -45,4 +45,9 @@ with parameters from the *Messages* buffer modification."
             (should (eq buf (current-buffer))))
         (when msg-ov (delete-overlay msg-ov))))))
 
+(ert-deftest test-generate-new-buffer-name-bug27966 ()
+  (should-not (string-equal "nil"
+                            (progn (get-buffer-create "nil")
+                                   (generate-new-buffer-name "nil")))))
+
 ;;; buffer-tests.el ends here
diff --git a/test/src/eval-tests.el b/test/src/eval-tests.el
index 03f408716b1..b98de0aa65e 100644
--- a/test/src/eval-tests.el
+++ b/test/src/eval-tests.el
@@ -59,4 +59,24 @@ Bug#24912 and Bug#24913."
         (should-error (,form ,arg) :type 'wrong-type-argument))
      t)))
 
+(ert-deftest eval-tests--if-dot-string ()
+  "Check that Emacs rejects (if . \"string\")."
+  (should-error (eval '(if . "abc")) :type 'wrong-type-argument)
+  (let ((if-tail (list '(setcdr if-tail "abc") t)))
+    (should-error (eval (cons 'if if-tail))))
+  (let ((if-tail (list '(progn (setcdr if-tail "abc") nil) t)))
+    (should-error (eval (cons 'if if-tail)))))
+
+(ert-deftest eval-tests--let-with-circular-defs ()
+  "Check that Emacs reports an error for (let VARS ...) when VARS is circular."
+  (let ((vars (list 'v)))
+    (setcdr vars vars)
+    (dolist (let-sym '(let let*))
+      (should-error (eval (list let-sym vars))))))
+
+(ert-deftest eval-tests--mutating-cond ()
+  "Check that Emacs doesn't crash on a cond clause that mutates during eval."
+  (let ((clauses (list '((progn (setcdr clauses "ouch") nil)))))
+    (should-error (eval (cons 'cond clauses)))))
+
 ;;; eval-tests.el ends here