Re: [PATCH] warnings: address -Wnull-dereference in reader.c

[Akim Demaille]

> Le 5 août 2018 à 16:40, Akim Demaille <address@hidden> a écrit :
> 
>> Le 8 juil. 2018 à 20:08, David Michael <address@hidden> a écrit :
>> 
>> This corrects a build failure when using GCC8 and configured with
>> the --enable-gcc-warnings and --enable-assert options:
> 
> hi David, thanks!
> 
> I will install this slightly different version of your patch:

And on top of that patch, I installed the following.
To fix a stupid mistake (will C stop requiring
void some day?), and to avoid the warning even with
NDEBUG set.

commit 93057cb7479db3196f77d71482951deb3ab5a06c
Author: Akim Demaille <address@hidden>
Date:   Wed Aug 15 13:51:36 2018 +0200

    fix incorrect C code
    
    Commit 3df32101e7978eaafa63bce8908de3dcae4d9cda introduced invalid C
    code.  Caught by GCC 7.3.0.
    
    * bootstrap.conf (gnulib_modules): We need assume.
    * src/reader.c (find_start_symbol): Fix the signature (too much C++,
    sorry...).
    Prefer 'assume' to 'assert', so that we don't have these warnings even
    when NDEBUG is defined.

diff --git a/bootstrap.conf b/bootstrap.conf
index d8c7d128..b2d0f974 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -17,7 +17,8 @@
 
 # gnulib modules used by this package.
 gnulib_modules='
-  argmatch assert calloc-posix close closeout config-h c-strcase
+  argmatch assert assume
+  calloc-posix close closeout config-h c-strcase
   configmake
   dirname
   error extensions fdl fopen-safer
diff --git a/src/reader.c b/src/reader.c
index 18a3fc2d..12faef96 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -726,20 +726,20 @@ prepare_percent_define_front_end_variables (void)
 /* Find the first LHS which is not a dummy.  */
 
 static symbol *
-find_start_symbol ()
+find_start_symbol (void)
 {
   symbol_list *res = grammar;
   for (;
-       res != NULL && symbol_is_dummy (res->content.sym);
+       res && symbol_is_dummy (res->content.sym);
        res = res->next)
     {
       for (res = res->next;
-           res != NULL && res->content.sym != NULL;
+           res && res->content.sym;
            res = res->next)
         continue;
-      aver (res != NULL);
+      assume (res);
     }
-  aver (res != NULL);
+  assume (res);
   return res->content.sym;
 }