Ensure f(**kw, &block) calls kw.to_hash before block.to_proc

Previously, block.to_proc was called first, by vm_caller_setup_arg_block.
kw.to_hash was called later inside CALLER_SETUP_ARG or setup_parameters_complex.

This adds a splatkw instruction that is inserted before sends with
ARGS_BLOCKARG and KW_SPLAT and without KW_SPLAT_MUT. This is not needed in the
KW_SPLAT_MUT case, because then you know the value is a hash, and you don't
need to call to_hash on it.

The splatkw instruction checks whether the second to top block is a hash,
and if not, replaces it with the value of calling to_hash on it (using
rb_to_hash_type).  As it is always before a send with ARGS_BLOCKARG and
KW_SPLAT, second to top is the keyword splat, and top is the passed block.

1 files changed, 3 insertions, 0 deletions

diff --git a/compile.c b/compile.c
index 05de0b8c87..caa6879de6 100644
--- a/compile.c
+++ b/compile.c
@@ -8827,6 +8827,9 @@ compile_call(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const node, co
         flag |= VM_CALL_FCALL;
     }
 
+    if ((flag & VM_CALL_ARGS_BLOCKARG) && (flag & VM_CALL_KW_SPLAT) && !(flag & VM_CALL_KW_SPLAT_MUT)) {
+        ADD_INSN(ret, line_node, splatkw);
+    }
     ADD_SEND_R(ret, line_node, mid, argc, parent_block, INT2FIX(flag), keywords);
 
     qcall_branch_end(iseq, ret, else_label, branches, node, line_node);