compile.c: avoid newarraykwsplat for argumentsv2_7_0_rc2

`foo(*rest, post, **empty_kw)` is compiled like
`foo(*rest + [post, **empty_kw])`, and `**empty_kw` is removed by
"newarraykwsplat" instruction.
However, the method call still has a flag of KW_SPLAT, so "post" is
considered as a keyword hash, which caused a segfault.
Note that the flag cannot be removed if "empty_kw" is not always empty.

This change fixes the issue by compiling arguments with "newarray"
instead of "newarraykwsplat".

[Bug #16442]

1 files changed, 8 insertions, 1 deletions

diff --git a/compile.c b/compile.c
index 98ee34afd0..c19112c853 100644
--- a/compile.c
+++ b/compile.c
@@ -5017,7 +5017,14 @@ setup_args_core(rb_iseq_t *iseq, LINK_ANCHOR *const args, const NODE *argn,
           case NODE_ARGSPUSH: {
             int next_is_list = (nd_type(argn->nd_head) == NODE_LIST);
             VALUE argc = setup_args_core(iseq, args, argn->nd_head, 1, NULL, NULL);
-            NO_CHECK(COMPILE(args, "args (cat: splat)", argn->nd_body));
+            if (nd_type(argn->nd_body) == NODE_LIST) {
+                /* This branch is needed to avoid "newarraykwsplat" [Bug #16442] */
+                int rest_len = compile_args(iseq, args, argn->nd_body, NULL, NULL);
+                ADD_INSN1(args, nd_line(argn), newarray, INT2FIX(rest_len));
+            }
+            else {
+                NO_CHECK(COMPILE(args, "args (cat: splat)", argn->nd_body));
+            }
             if (flag) {
                 *flag |= VM_CALL_ARGS_SPLAT;
                 /* This is a dirty hack.  It traverses the AST twice.