diff --git a/parse.y b/parse.y
index da91b53a02..6d04f4175e 100644
--- a/parse.y
+++ b/parse.y
@@ -3409,6 +3409,7 @@ opt_block_param	: none
 
 block_param_def	: '|' opt_bv_decl '|'
 		    {
+			current_arg = 0;
 		    /*%%%*/
 			$$ = 0;
 		    /*%
@@ -3427,6 +3428,7 @@ block_param_def	: '|' opt_bv_decl '|'
 		    }
 		| '|' block_param opt_bv_decl '|'
 		    {
+			current_arg = 0;
 		    /*%%%*/
 			$$ = $2;
 		    /*%
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index 55af33fe48..e70470555c 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -171,6 +171,11 @@ class TestSyntax < Test::Unit::TestCase
     assert_warn("") do
       o.instance_eval("def foo(var: def bar(var) var; end) var end")
     end
+
+    o = Object.new
+    assert_warn("") do
+      o.instance_eval("proc {|var: 1| var}")
+    end
   end
 
   def test_optional_self_reference
@@ -207,6 +212,11 @@ class TestSyntax < Test::Unit::TestCase
     assert_warn("") do
       o.instance_eval("def foo(var = def bar(var) var; end) var end")
     end
+
+    o = Object.new
+    assert_warn("") do
+      o.instance_eval("proc {|var = 1| var}")
+    end
   end
 
   def test_warn_grouped_expression