Check that variable lists are actually lists

'let' and 'let*' document that their first argument has to be a list,
but don't check for that; instead, they allow (and silently ignore)
other types.  Introduce an explicit type check.

* src/eval.c (Flet, FletX): Check that the variable list is indeed a
list.
* test/src/eval-tests.el: Add unit tests.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/eval.c b/src/eval.c
index 1f8d4099324..c05c8d8f8de 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -857,6 +857,7 @@ usage: (let* VARLIST BODY...)  */)
   lexenv = Vinternal_interpreter_environment;
 
   varlist = XCAR (args);
+  CHECK_LIST (varlist);
   while (CONSP (varlist))
     {
       QUIT;
@@ -917,6 +918,7 @@ usage: (let VARLIST BODY...)  */)
   USE_SAFE_ALLOCA;
 
   varlist = XCAR (args);
+  CHECK_LIST (varlist);
 
   /* Make space to hold the values to give the bound variables.  */
   elt = Flength (varlist);