diff --git a/source/dub/dub.d b/source/dub/dub.d
index 3dc9402..2314c80 100644
--- a/source/dub/dub.d
+++ b/source/dub/dub.d
@@ -80,8 +80,14 @@
 		m_systemConfig = jsonFromFile(m_systemDubPath ~ "settings.json", true);
 
 		PackageSupplier[] ps = additional_package_suppliers;
-		if (auto pp = "registryUrls" in m_userConfig) ps ~= deserializeJson!(string[])(*pp).map!(url => new RegistryPackageSupplier(Url(url))).array;
-		if (auto pp = "registryUrls" in m_systemConfig) ps ~= deserializeJson!(string[])(*pp).map!(url => new RegistryPackageSupplier(Url(url))).array;
+		if (auto pp = "registryUrls" in m_userConfig)
+			ps ~= deserializeJson!(string[])(*pp)
+				.map!(url => cast(PackageSupplier)new RegistryPackageSupplier(Url(url)))
+				.array;
+		if (auto pp = "registryUrls" in m_systemConfig)
+			ps ~= deserializeJson!(string[])(*pp)
+				.map!(url => cast(PackageSupplier)new RegistryPackageSupplier(Url(url)))
+				.array;
 		ps ~= defaultPackageSuppliers();
 
 		m_packageSuppliers = ps;
diff --git a/source/dub/packagesupplier.d b/source/dub/packagesupplier.d
index 4101321..27e4d23 100644
--- a/source/dub/packagesupplier.d
+++ b/source/dub/packagesupplier.d
@@ -22,14 +22,14 @@
 /// Supplies packages, this is done by supplying the latest possible version
 /// which is available.
 interface PackageSupplier {
+	/// Returns a hunman readable representation of the supplier
+	@property string description();
+
 	/// path: absolute path to store the package (usually in a zip format)
 	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release);
 	
 	/// returns the metadata for the package
 	Json getPackageDescription(string packageId, Dependency dep, bool pre_release);
-
-	/// Returns a hunman readable representation of the supplier
-	string toString();
 }
 
 class FileSystemPackageSupplier : PackageSupplier {
@@ -39,7 +39,7 @@
 
 	this(Path root) { m_path = root; }
 
-	override string toString() { return "file repository at "~m_path.toNativeString(); }
+	override @property string description() { return "file repository at "~m_path.toNativeString(); }
 	
 	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release)
 	{
@@ -98,7 +98,7 @@
 		m_registryUrl = registry;
 	}
 
-	override string toString() { return "registry at "~m_registryUrl.toString(); }
+	override @property string description() { return "registry at "~m_registryUrl.toString(); }
 	
 	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release)
 	{
diff --git a/source/dub/project.d b/source/dub/project.d
index cb9d1cc..bba506a 100644
--- a/source/dub/project.d
+++ b/source/dub/project.d
@@ -601,7 +601,7 @@
 								p = sp;
 								break;
 							} catch (Exception e) {
-								logDiagnostic("No metadata for %s: %s", ps.toString(), e.msg);
+								logDiagnostic("No metadata for %s: %s", ps.description, e.msg);
 							}
 						}
 						enforce(p !is null, "Could not find package candidate for "~pkg~" "~reqDep.dependency.toString());