Fix issue resolving const dependencies

Hypodermic.Tests/CMakeLists.txt

@@ -28,6 +28,7 @@ set(HypodermicTests_sources
     ProvidedInstanceFactoryRegistrationTests.cpp
     ProvidedInstanceRegistrationTests.cpp
     RegistrationTests.cpp
+    ResolveConstPtrTests.cpp
     RuntimeRegistrationTests.cpp
     UseIfNoneTests.cpp
 )

Hypodermic.Tests/ResolveConstPtrTests.cpp

@@ -0,0 +1,91 @@
+#include "stdafx.h"
+
+#include "Hypodermic/ContainerBuilder.h"
+
+
+namespace Hypodermic
+{
+namespace Testing
+{
+namespace
+{
+
+    class Foo
+    {
+    public:
+        int value() const
+        {
+            return 42;
+        }
+    };
+
+    class Bar
+    {
+    public:
+        explicit Bar(std::shared_ptr<Foo> foo) noexcept : _foo(std::move(foo))
+        { }
+
+        const std::shared_ptr<Foo>& foo() const noexcept
+        {
+            return _foo;
+        }
+
+    private:
+        std::shared_ptr<Foo> _foo;
+    };
+
+    class Baz
+    {
+    public:
+        explicit Baz(std::shared_ptr<const Foo> foo) noexcept : _foo(std::move(foo))
+        { }
+
+        const std::shared_ptr<const Foo>& foo() const noexcept
+        {
+            return _foo;
+        }
+
+    private:
+        std::shared_ptr<const Foo> _foo;
+    };
+
+} // namespace
+
+    BOOST_AUTO_TEST_SUITE(ResolveConstPtrTests)
+
+    BOOST_AUTO_TEST_CASE(should_resolve_non_const_ptr)
+    {
+        // Arrange
+        ContainerBuilder builder;
+        builder.registerType<Foo>();
+        builder.registerType<Bar>();
+        auto container = builder.build();
+
+        // Act
+        const auto bar = container->resolve<Bar>();
+        auto value = bar->foo()->value();
+
+        // Assert
+        BOOST_CHECK_EQUAL(value, 42);
+    }
+
+    BOOST_AUTO_TEST_CASE(should_resolve_const_ptr)
+    {
+        // Arrange
+        ContainerBuilder builder;
+        builder.registerType<Foo>();
+        builder.registerType<Baz>();
+        auto container = builder.build();
+
+        // Act
+        const auto baz = container->resolve<Bar>();
+        auto value = baz->foo()->value();
+
+        // Assert
+        BOOST_CHECK_EQUAL(value, 42);
+    }
+
+    BOOST_AUTO_TEST_SUITE_END()
+
+} // namespace Testing
+} // namespace Hypodermic

Hypodermic/ArgumentResolver.h

@@ -38,6 +38,25 @@ namespace Traits
     };
 
 
+	template <class TArg>
+	struct ArgumentResolver< std::shared_ptr< const TArg > >
+	{
+		typedef std::shared_ptr< const TArg > Type;
+
+		template <class TRegistration, class TResolutionContext>
+		static Type resolve(const TRegistration& registration, TResolutionContext& resolutionContext)
+		{
+			static_assert(IsComplete< TArg >::value, "TArg should be a complete type");
+
+			auto&& factory = registration.getDependencyFactory(Utils::getMetaTypeInfo< TArg >());
+			if (factory)
+				return std::shared_ptr< const TArg >(std::static_pointer_cast<TArg>(factory(resolutionContext.componentContext())));
+
+			return std::shared_ptr< const TArg >(resolutionContext.componentContext().template resolve< TArg >());
+		}
+	};
+
+
     template <class TArg>
     struct ArgumentResolver< std::vector< std::shared_ptr< TArg > > >
     {