parse.y: workaround for warnings

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

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60339 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 35 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index 01047a8dc5..028f872161 100644
--- a/parse.y
+++ b/parse.y
@@ -9927,6 +9927,33 @@ splat_array(NODE* node)
     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 *parser, NODE *node)
 	    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;
 	}
diff --git a/test/ruby/test_parse.rb b/test/ruby/test_parse.rb
index 5b973a0901..8830dbec30 100644
--- a/test/ruby/test_parse.rb
+++ b/test/ruby/test_parse.rb
@@ -890,6 +890,7 @@ x = __ENCODING__
     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