diff --git a/lib/rubygems/specification.rb b/lib/rubygems/specification.rb
index d3d6d9ca20..0bd62c3648 100644
--- a/lib/rubygems/specification.rb
+++ b/lib/rubygems/specification.rb
@@ -557,7 +557,7 @@ class Gem::Specification < Gem::BasicSpecification
 
   def add_runtime_dependency(gem, *requirements)
     if requirements.uniq.size != requirements.size
-      warn "WARNING: duplicate dependency #{requirements}"
+      warn "WARNING: duplicated #{gem} dependency #{requirements}"
     end
 
     add_dependency_with_type(gem, :runtime, requirements)
diff --git a/test/rubygems/test_gem_specification.rb b/test/rubygems/test_gem_specification.rb
index cd00f74c93..b99d12a044 100644
--- a/test/rubygems/test_gem_specification.rb
+++ b/test/rubygems/test_gem_specification.rb
@@ -3052,7 +3052,7 @@ Please report a bug if this causes problems.
   end
 
   def test_duplicate_runtime_dependency
-    expected = "WARNING: duplicate dependency [\"~> 3.0\", \"~> 3.0\"]\n"
+    expected = "WARNING: duplicated b dependency [\"~> 3.0\", \"~> 3.0\"]\n"
     assert_output nil, expected do
       @a1.add_runtime_dependency "b", "~> 3.0", "~> 3.0"
     end