GCC wrongly accepts [*] in old-style parameter definitions because because parm_flag is set on the scope used for those definitions and, unlike the case of a prototype in a function definition, there is no subsequent check to disallow this invalid usage. This patch adds such a check. (At this point we don't have location information for the [*], so the diagnostic location isn't ideal.)
Bootstrapped with no regressions for x86_64-pc-linux-gnu. Applied to mainline. gcc/c: 2019-12-03 Joseph Myers <jos...@codesourcery.com> PR c/88704 * c-decl.c (store_parm_decls_oldstyle): Diagnose use of [*] in old-style parameter definitions. gcc/testsuite: 2019-12-03 Joseph Myers <jos...@codesourcery.com> PR c/88704 * gcc.dg/vla-25.c: New test. Index: gcc/c/c-decl.c =================================================================== --- gcc/c/c-decl.c (revision 278912) +++ gcc/c/c-decl.c (working copy) @@ -9394,6 +9394,9 @@ store_parm_decls_oldstyle (tree fndecl, const stru "old-style function definition"); } + if (current_scope->had_vla_unspec) + error ("%<[*]%> not allowed in other than function prototype scope"); + /* Match each formal parameter name with its declaration. Save each decl in the appropriate TREE_PURPOSE slot of the parmids chain. */ for (parm = parmids; parm; parm = TREE_CHAIN (parm)) Index: gcc/testsuite/gcc.dg/vla-25.c =================================================================== --- gcc/testsuite/gcc.dg/vla-25.c (nonexistent) +++ gcc/testsuite/gcc.dg/vla-25.c (working copy) @@ -0,0 +1,9 @@ +/* Test [*] diagnosed on old-style parameter declaration. PR c/88704. */ +/* { dg-do compile } */ +/* { dg-options "-std=c99 -pedantic-errors" } */ + +void +f (x) + int x[*]; +{ /* { dg-error "not allowed in other than function prototype scope" } */ +} -- Joseph S. Myers jos...@codesourcery.com