super{} doesn't use block

`super(){}`, `super{}` and `super(&b)` doesn't use the given
block so warn unused block warning when calling a method which
doesn't use block with above `super` expressions.

e.g.: `def f = super{B1}` (warn on `f{B2}` because `B2` is not used.

compile.c

@@ -9369,10 +9369,10 @@ compile_super(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const node, i
     unsigned int flag = 0;
     struct rb_callinfo_kwarg *keywords = NULL;
     const rb_iseq_t *parent_block = ISEQ_COMPILE_DATA(iseq)->current_block;
+    int use_block = 1;
 
     INIT_ANCHOR(args);
     ISEQ_COMPILE_DATA(iseq)->current_block = NULL;
-    ISEQ_BODY(ISEQ_BODY(iseq)->local_iseq)->param.flags.use_block = 1;
 
     if (type == NODE_SUPER) {
         VALUE vargc = setup_args(iseq, args, RNODE_SUPER(node)->nd_args, &flag, &keywords);
@@ -9381,6 +9381,10 @@ compile_super(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const node, i
         if ((flag & VM_CALL_ARGS_BLOCKARG) && (flag & VM_CALL_KW_SPLAT) && !(flag & VM_CALL_KW_SPLAT_MUT)) {
             ADD_INSN(args, node, splatkw);
         }
+
+        if (flag & VM_CALL_ARGS_BLOCKARG) {
+            use_block = 0;
+        }
     }
     else {
         /* NODE_ZSUPER */
@@ -9474,6 +9478,10 @@ compile_super(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const node, i
         }
     }
 
+    if (use_block && parent_block == NULL) {
+        ISEQ_BODY(ISEQ_BODY(iseq)->local_iseq)->param.flags.use_block = 1;
+    }
+
     flag |= VM_CALL_SUPER | VM_CALL_FCALL;
     if (type == NODE_ZSUPER) flag |= VM_CALL_ZSUPER;
     ADD_INSN(ret, node, putself);

test/ruby/test_method.rb

@@ -1663,28 +1663,34 @@ def initialize
 
     assert_in_out_err '-w', <<-'RUBY' do |_out, err, _status|
       class C0
-        def foo = nil
-        def bar = nil
-        def baz = nil
-        def qux = nil
+        def f1 = nil
+        def f2 = nil
+        def f3 = nil
+        def f4 = nil
+        def f5 = nil
+        def f6 = nil
       end
 
       class C1 < C0
-        def foo = super
-        def bar = super()
-        def baz(&_) = super(&_)
-        def qux = super(&nil)
+        def f1 = super         # zsuper / use
+        def f2 = super()       # super  / use
+        def f3(&_) = super(&_) # super  / use
+        def f4 = super(&nil)   # super  / unuse
+        def f5 = super(){}     # super  / unuse
+        def f6 = super{}       # zsuper / unuse
       end
 
-      C1.new.foo{} # no warning
-      C1.new.bar{} # no warning
-      C1.new.baz{} # no warning
-      # C1.new.qux{} # TODO: warning line:16 but not supported yet.
+      C1.new.f1{} # no warning
+      C1.new.f2{} # no warning
+      C1.new.f3{} # no warning
+      C1.new.f4{} # warning
+      C1.new.f5{} # warning
+      C1.new.f6{} # warning
     RUBY
-      assert_equal 0, err.size
-      # TODO
-      # assert_equal 1, err.size
-      # assert_match(/-:16: warning.+qux/, err.join)
+      assert_equal 3, err.size, err.join("\n")
+      assert_match(/-:22: warning.+f4/, err.join)
+      assert_match(/-:23: warning.+f5/, err.join)
+      assert_match(/-:24: warning.+f6/, err.join)
     end
   end
 end