diff --git a/tests/vibe.web.web/source/app.d b/tests/vibe.web.web/source/app.d
index 1a73f08367..ea0181e2ac 100644
--- a/tests/vibe.web.web/source/app.d
+++ b/tests/vibe.web.web/source/app.d
@@ -15,7 +15,7 @@ class Service {
 	@noRoute void getFoo(HTTPServerResponse res) { res.writeBody("oops"); }
 	void getBar(HTTPServerResponse res) { res.writeBody("ok"); }
 	// you can work with Json objects directly
-	auto postJson(Json json) { return json; }
+	auto postJson(Json _json) { return _json; }
 }
 
 shared static this()
diff --git a/web/vibe/web/web.d b/web/vibe/web/web.d
index 1c97331721..335d4dfeda 100644
--- a/web/vibe/web/web.d
+++ b/web/vibe/web/web.d
@@ -912,6 +912,8 @@ private void handleRequest(string M, alias overload, C, ERROR...)(HTTPServerRequ
 			else static if (is(PT == HTTPServerRequest) || is(PT == HTTPRequest)) params[i] = req;
 			else static if (is(PT == HTTPServerResponse) || is(PT == HTTPResponse)) params[i] = res;
 			else static if (is(PT == Json)) {
+				import std.algorithm.comparison : among;
+				static assert(param_names[i].among("_body", "_json", "The Json parameter must be named _body or _json."));
 				enforceBadRequest(req.json.type != Json.Type.undefined, "Invalid Json passed.");
 				params[i] = req.json;
 			}