diff --git a/core/module/const_source_location_spec.rb b/core/module/const_source_location_spec.rb
new file mode 100644
index 0000000000..757d831708
--- /dev/null
+++ b/core/module/const_source_location_spec.rb
@@ -0,0 +1,227 @@
+require_relative '../../spec_helper'
+require_relative '../../fixtures/constants'
+require_relative 'fixtures/constants_autoload'
+
+describe "Module#const_source_location" do
+  before do
+    @constants_fixture_path = File.expand_path('../../fixtures/constants.rb', __dir__)
+  end
+
+  ruby_version_is "2.7" do
+    # NOTE: please keep this specs on the top to avoid breaking specs
+    describe "with dynamically assigned constants" do
+      it "searches a path in the immediate class or module first" do
+        ConstantSpecs::ClassA::CS_CONST301 = :const301_1
+        ConstantSpecs::ClassA.const_source_location(:CS_CONST301).should == [__FILE__, 14]
+
+        ConstantSpecs::ModuleA::CS_CONST301 = :const301_2
+        ConstantSpecs::ModuleA.const_source_location(:CS_CONST301).should == [__FILE__, 17]
+
+        ConstantSpecs::ParentA::CS_CONST301 = :const301_3
+        ConstantSpecs::ParentA.const_source_location(:CS_CONST301).should == [__FILE__, 20]
+
+        ConstantSpecs::ContainerA::ChildA::CS_CONST301 = :const301_5
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST301).should == [__FILE__, 23]
+      end
+
+      it "searches a path in a module included in the immediate class before the superclass" do
+        ConstantSpecs::ParentB::CS_CONST302 = :const302_1
+        ConstantSpecs::ModuleF::CS_CONST302 = :const302_2
+        ConstantSpecs::ContainerB::ChildB.const_source_location(:CS_CONST302).should == [__FILE__, 29]
+      end
+
+      it "searches a path in the superclass before a module included in the superclass" do
+        ConstantSpecs::ModuleE::CS_CONST303 = :const303_1
+        ConstantSpecs::ParentB::CS_CONST303 = :const303_2
+        ConstantSpecs::ContainerB::ChildB.const_source_location(:CS_CONST303).should == [__FILE__, 35]
+      end
+
+      it "searches a path in a module included in the superclass" do
+        ConstantSpecs::ModuleA::CS_CONST304 = :const304_1
+        ConstantSpecs::ModuleE::CS_CONST304 = :const304_2
+        ConstantSpecs::ContainerB::ChildB.const_source_location(:CS_CONST304).should == [__FILE__, 41]
+      end
+
+      it "searches a path in the superclass chain" do
+        ConstantSpecs::ModuleA::CS_CONST305 = :const305
+        ConstantSpecs::ContainerB::ChildB.const_source_location(:CS_CONST305).should == [__FILE__, 46]
+      end
+
+      it "returns path to a toplevel constant when the receiver is a Class" do
+        Object::CS_CONST306 = :const306
+        ConstantSpecs::ContainerB::ChildB.const_source_location(:CS_CONST306).should == [__FILE__, 51]
+      end
+
+      it "returns path to a toplevel constant when the receiver is a Module" do
+        Object::CS_CONST308 = :const308
+        ConstantSpecs.const_source_location(:CS_CONST308).should == [__FILE__, 56]
+        ConstantSpecs::ModuleA.const_source_location(:CS_CONST308).should == [__FILE__, 56]
+      end
+
+      it "returns path to the updated value of a constant" do
+        ConstantSpecs::ClassB::CS_CONST309 = :const309_1
+        ConstantSpecs::ClassB.const_source_location(:CS_CONST309).should == [__FILE__, 62]
+
+        -> {
+          ConstantSpecs::ClassB::CS_CONST309 = :const309_2
+        }.should complain(/already initialized constant/)
+
+        ConstantSpecs::ClassB.const_source_location(:CS_CONST309).should == [__FILE__, 66]
+      end
+    end
+
+    describe "with statically assigned constants" do
+      it "searches location path the immediate class or module first" do
+        ConstantSpecs::ClassA.const_source_location(:CS_CONST10).should == [@constants_fixture_path, 78]
+        ConstantSpecs::ModuleA.const_source_location(:CS_CONST10).should == [@constants_fixture_path, 36]
+        ConstantSpecs::ParentA.const_source_location(:CS_CONST10).should == [@constants_fixture_path, 100]
+        ConstantSpecs::ContainerA.const_source_location(:CS_CONST10).should == [@constants_fixture_path, 120]
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST10).should == [@constants_fixture_path, 137]
+      end
+
+      it "searches location path a module included in the immediate class before the superclass" do
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST15).should == [@constants_fixture_path, 52]
+      end
+
+      it "searches location path the superclass before a module included in the superclass" do
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST11).should == [@constants_fixture_path, 101]
+      end
+
+      it "searches location path a module included in the superclass" do
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST12).should == [@constants_fixture_path, 46]
+      end
+
+      it "searches location path the superclass chain" do
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST13).should == [@constants_fixture_path, 38]
+      end
+
+      it "returns location path a toplevel constant when the receiver is a Class" do
+        ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST1).should == [@constants_fixture_path, 30]
+      end
+
+      it "returns location path a toplevel constant when the receiver is a Module" do
+        ConstantSpecs.const_source_location(:CS_CONST1).should == [@constants_fixture_path, 30]
+        ConstantSpecs::ModuleA.const_source_location(:CS_CONST1).should == [@constants_fixture_path, 30]
+      end
+    end
+
+    it "return empty path if constant defined in C code" do
+      Object.const_source_location(:String).should == []
+    end
+
+    it "accepts a String or Symbol name" do
+      Object.const_source_location(:CS_CONST1).should == [@constants_fixture_path, 30]
+      Object.const_source_location("CS_CONST1").should == [@constants_fixture_path, 30]
+    end
+
+    it "returns nil if no constant is defined in the search path" do
+      ConstantSpecs.const_source_location(:CS_CONSTX).should == nil
+    end
+
+    it "raises a NameError if the name does not start with a capital letter" do
+      -> { ConstantSpecs.const_source_location "name" }.should raise_error(NameError)
+    end
+
+    it "raises a NameError if the name starts with a non-alphabetic character" do
+      -> { ConstantSpecs.const_source_location "__CONSTX__" }.should raise_error(NameError)
+      -> { ConstantSpecs.const_source_location "@CS_CONST1" }.should raise_error(NameError)
+      -> { ConstantSpecs.const_source_location "!CS_CONST1" }.should raise_error(NameError)
+    end
+
+    it "raises a NameError if the name contains non-alphabetic characters except '_'" do
+      Object.const_source_location("CS_CONST1").should == [@constants_fixture_path, 30]
+      -> { ConstantSpecs.const_source_location "CS_CONST1=" }.should raise_error(NameError)
+      -> { ConstantSpecs.const_source_location "CS_CONST1?" }.should raise_error(NameError)
+    end
+
+    it "calls #to_str to convert the given name to a String" do
+      name = mock("ClassA")
+      name.should_receive(:to_str).and_return("ClassA")
+      ConstantSpecs.const_source_location(name).should == [@constants_fixture_path, 77]
+    end
+
+    it "raises a TypeError if conversion to a String by calling #to_str fails" do
+      name = mock('123')
+      -> { ConstantSpecs.const_source_location(name) }.should raise_error(TypeError)
+
+      name.should_receive(:to_str).and_return(123)
+      -> { ConstantSpecs.const_source_location(name) }.should raise_error(TypeError)
+    end
+
+    it "does not search the singleton class of a Class or Module" do
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST14).should == nil
+      ConstantSpecs.const_source_location(:CS_CONST14).should == nil
+    end
+
+    it "does not search the containing scope" do
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST20).should == [@constants_fixture_path, 103]
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST5) == nil
+    end
+
+    it "returns nil if the constant is defined in the receiver's superclass and the inherit flag is false" do
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST4, false).should == nil
+    end
+
+    it "searches into the receiver superclasses if the inherit flag is true" do
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST4, true).should == [@constants_fixture_path, 99]
+    end
+
+    it "returns nil when the receiver is a Module, the constant is defined at toplevel and the inherit flag is false" do
+      ConstantSpecs::ModuleA.const_source_location(:CS_CONST1, false).should == nil
+    end
+
+    it "returns nil when the receiver is a Class, the constant is defined at toplevel and the inherit flag is false" do
+      ConstantSpecs::ContainerA::ChildA.const_source_location(:CS_CONST1, false).should == nil
+    end
+
+    it "accepts a toplevel scope qualifier" do
+      ConstantSpecs.const_source_location("::CS_CONST1").should == [@constants_fixture_path, 30]
+    end
+
+    it "accepts a scoped constant name" do
+      ConstantSpecs.const_source_location("ClassA::CS_CONST10").should == [@constants_fixture_path, 78]
+    end
+
+    it "raises a NameError if the name includes two successive scope separators" do
+      -> { ConstantSpecs.const_source_location("ClassA::::CS_CONST10") }.should raise_error(NameError)
+    end
+
+    it "raises a NameError if only '::' is passed" do
+      -> { ConstantSpecs.const_source_location("::") }.should raise_error(NameError)
+    end
+
+    it "raises a NameError if a Symbol has a toplevel scope qualifier" do
+      -> { ConstantSpecs.const_source_location(:'::CS_CONST1') }.should raise_error(NameError)
+    end
+
+    it "raises a NameError if a Symbol is a scoped constant name" do
+      -> { ConstantSpecs.const_source_location(:'ClassA::CS_CONST10') }.should raise_error(NameError)
+    end
+
+    it "does search private constants path" do
+       ConstantSpecs.const_source_location(:CS_PRIVATE).should == [@constants_fixture_path, 284]
+    end
+
+    context 'autoload' do
+      before do
+        @constants_autoload_path = File.expand_path('fixtures/constants_autoload', __dir__)
+      end
+
+      it 'does search path in autoload declaration' do
+        Object.const_source_location('CSAutoloadA').should == [@constants_autoload_path + '_a.rb', 1]
+      end
+
+      it 'does search path in autoload declaration a constant with a toplevel scope qualifier' do
+        Object.const_source_location('::CSAutoloadB').should == [@constants_autoload_path + '_b.rb', 1]
+      end
+
+      it 'does search path in autoload declaration a module and resolve a constant within' do
+        Object.const_source_location('CSAutoloadC::CONST').should == [@constants_autoload_path + '_c.rb', 2]
+      end
+
+      it 'does autoload a non-toplevel module' do
+        Object.const_source_location('CSAutoloadD::InnerModule').should == [@constants_autoload_path + '_d.rb', 2]
+      end
+    end
+  end
+end