[PRISM] Fix splat and block in aset

prism_compile.c

@@ -2713,6 +2713,10 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
     if (pm_node->flags & PM_CALL_NODE_FLAGS_ATTRIBUTE_WRITE) {
         if (flags & VM_CALL_ARGS_BLOCKARG) {
             ADD_INSN1(ret, &dummy_line_node, topn, INT2FIX(1));
+            if (flags & VM_CALL_ARGS_SPLAT) {
+                ADD_INSN1(ret, &dummy_line_node, putobject, INT2FIX(-1));
+                ADD_SEND_WITH_FLAG(ret, &dummy_line_node, idAREF, INT2FIX(1), INT2FIX(0));
+            }
             ADD_INSN1(ret, &dummy_line_node, setn, INT2FIX(orig_argc + 3));
             PM_POP;
         }

test/ruby/test_compile_prism.rb

@@ -1771,6 +1771,15 @@ end
         obj[&p] = 4
       RUBY
 
+      # Test splat and block inside of []=
+      assert_prism_eval(<<~RUBY)
+        obj = Object.new
+        def obj.[]=(a, b); end
+
+        p = proc {}
+        obj[*[1], &p] = 4
+      RUBY
+
       assert_prism_eval(<<-CODE)
         def self.prism_opt_var_trail_hash(a = nil, *b, c, **d); end
         prism_opt_var_trail_hash("a")