nobu	2017-10-22 10:37:36 +0900 (Sun, 22 Oct 2017)

  New Revision: 60339

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=60339

  Log:
    parse.y: workaround for warnings
    
    * parse.y (mark_lvar_used): enable workaround to suppress unused
      local variables.  [ruby-core:82656] [Bug #13872]

  Modified files:
    trunk/parse.y
    trunk/test/ruby/test_parse.rb
Index: parse.y
===================================================================
--- parse.y	(revision 60338)
+++ parse.y	(revision 60339)
@@ -9927,6 +9927,33 @@ splat_array(NODE* node) https://github.com/ruby/ruby/blob/trunk/parse.y#L9927
     return 0;
 }
 
+static void
+mark_lvar_used(struct parser_params *parser, NODE *rhs)
+{
+    ID *vidp = NULL;
+    if (!rhs) return;
+    switch (nd_type(rhs)) {
+      case NODE_LASGN:
+	if (local_id_ref(rhs->nd_vid, vidp)) {
+	    if (vidp) *vidp |= LVAR_USED;
+	}
+	break;
+      case NODE_DASGN:
+      case NODE_DASGN_CURR:
+	if (dvar_defined_ref(rhs->nd_vid, vidp)) {
+	    if (vidp) *vidp |= LVAR_USED;
+	}
+	break;
+#if 0
+      case NODE_MASGN:
+	for (rhs = rhs->nd_head; rhs; rhs = rhs->nd_next) {
+	    mark_lvar_used(parser, rhs->nd_head);
+	}
+	break;
+#endif
+    }
+}
+
 static NODE *
 node_assign_gen(struct parser_params *parser, NODE *lhs, NODE *rhs, int column)
 {
@@ -10007,6 +10034,13 @@ value_expr_gen(struct parser_params *par https://github.com/ruby/ruby/blob/trunk/parse.y#L10034
 	    node = node->nd_2nd;
 	    break;
 
+	  case NODE_LASGN:
+	  case NODE_DASGN:
+	  case NODE_DASGN_CURR:
+	  case NODE_MASGN:
+	    mark_lvar_used(parser, node);
+	    return TRUE;
+
 	  default:
 	    return TRUE;
 	}
Index: test/ruby/test_parse.rb
===================================================================
--- test/ruby/test_parse.rb	(revision 60338)
+++ test/ruby/test_parse.rb	(revision 60339)
@@ -890,6 +890,7 @@ x = __ENCODING__ https://github.com/ruby/ruby/blob/trunk/test/ruby/test_parse.rb#L890
     assert_warning(/#{a}/) {o.instance_eval("def foo; #{a}=1; nil; end")}
     o = Object.new
     assert_warning(/assigned but unused variable/) {o.instance_eval("def foo; tap {a=1; a()}; end")}
+    assert_warning('') {o.instance_eval("def bar; a=a=1; nil; end")}
   end
 
   def test_named_capture_conflict

--
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