Fix REST client to build "id" URLs correctly.

See also #1209.

source/vibe/web/rest.d

@@ -1109,7 +1109,7 @@ private string genClientBody(alias Func)() {
 			request_str = q{
 				if (m_settings.stripTrailingUnderscore && url__.endsWith("_"))
 					url__ = url__[0 .. $-1];
-				url__ = %s ~ adjustMethodStyle(url__, m_methodStyle);
+				url__ = concatURL(%s, adjustMethodStyle(url__, m_methodStyle));
 			}.format(url_prefix);
 		} else {
 			import std.array : split;

tests/restclient/source/app.d

@@ -4,6 +4,8 @@ import vibe.vibe;
 
 interface ITestAPI
 {
+	@property ISub sub();
+
 	@method(HTTPMethod.POST) @path("other/path")
 	string info();
 	string getInfo();
@@ -15,20 +17,36 @@ interface ITestAPI
 	int testID1(int _id);
 	@path("idtest2")
 	int testID2(int id); // the special "id" parameter
+	int get(int id); // the special "id" parameter on "/"" path
 	int testKeyword(int body_, int const_);
 }
 
+interface ISub {
+	int get(int id);
+}
+
 class TestAPI : ITestAPI
 {
+	SubAPI m_sub;
+
+	this() { m_sub = new SubAPI; }
+
+	@property SubAPI sub() { return m_sub; }
+
 	string getInfo() { return "description"; }
 	string info() { return "description2"; }
 	string customParameters(string _param, string _param2) { return _param ~ _param2; }
 	int customParameters2(int _param, bool _param2) { return _param2 ? _param : -_param; }
 	int testID1(int _id) { return _id; }
 	int testID2(int id) { return id; }
+	int get(int id) { return id; }
 	int testKeyword(int body_, int const_) { return body_ + const_; }
 }
 
+class SubAPI : ISub {
+	int get(int id) { return id; }
+}
+
 void runTest()
 {
 	auto router = new URLRouter;
@@ -47,6 +65,8 @@ void runTest()
 	assert(api.customParameters2(10, true) == 10);
 	assert(api.testID1(2) == 2);
 	assert(api.testID2(3) == 3);
+	assert(api.get(4) == 4);
+	assert(api.sub.get(5) == 5);
 	assert(api.testKeyword(3, 4) == 7);
 	exitEventLoop(true);
 }