[PRISM] Use the splatkw instruction

Fixes ruby/prism#2272.

prism_compile.c

@@ -2749,13 +2749,17 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
         else if (!popped) {
             ADD_INSN1(ret, &dummy_line_node, setn, INT2FIX(orig_argc + 1));
         }
+    }
+
+    if ((flags & VM_CALL_KW_SPLAT) && (flags & VM_CALL_ARGS_BLOCKARG) && !(flags & VM_CALL_KW_SPLAT_MUT)) {
+        ADD_INSN(ret, &dummy_line_node, splatkw);
+    }
 
     ADD_SEND_R(ret, &dummy_line_node, method_id, INT2FIX(orig_argc), block_iseq, INT2FIX(flags), kw_arg);
+
+    if (pm_node->flags & PM_CALL_NODE_FLAGS_ATTRIBUTE_WRITE) {
         PM_POP_UNLESS_POPPED;
     }
-    else {
-        ADD_SEND_R(ret, &dummy_line_node, method_id, INT2FIX(orig_argc), block_iseq, INT2FIX(flags), kw_arg);
-    }
 
     if (call_node->base.flags & PM_CALL_NODE_FLAGS_SAFE_NAVIGATION) {
         ADD_INSNL(ret, &dummy_line_node, jump, end_label);

test/ruby/test_compile_prism.rb

@@ -827,6 +827,28 @@ module Prism
 
         o.bar(hello: "world")
       RUBY
+
+      # Test that AssocSplatNode is evaluated before BlockArgumentNode using
+      # the splatkw instruction
+      assert_prism_eval(<<~RUBY)
+        o = Struct.new(:ary) do
+          def to_hash
+            ary << :to_hash
+            {}
+          end
+
+          def to_proc
+            ary << :to_proc
+            -> {}
+          end
+
+          def t(...); end
+        end.new
+        o.ary = []
+
+        o.t(**o, &o)
+        o.ary
+      RUBY
     end
 
     def test_HashNode