Add two test cases with an unclear diagnostics

Author: slavapestov

test/Constraints/diagnostics.swift

@@ -777,4 +777,7 @@ class SR1594 {
   }
 }
 
-
+// FIXME: Bad diagnostic
+func secondArgumentNotLabeled(a:Int, _ b: Int) { }
+secondArgumentNotLabeled(10, 20)
+// expected-error@-1 {{argument '_' must precede unnamed parameter #0}}

test/Generics/invalid.swift

@@ -71,3 +71,11 @@ func badDiagnostic2() {
   // expected-note@-2 {{overloads for 'eatDinnerConcrete' exist with these partially matching parameter lists: (d: Pizzas<ChiliFlakes>.NewYork, t: Deli<ChiliFlakes>.Pepperoni), (d: Pizzas<Pepper>.DeepDish, t: Deli<Pepper>.Pepperoni)}}
 
 }
+
+// Real error is that we cannot infer the generic parameter from context
+
+func takesAny(_ a: Any) {}
+
+func badDiagnostic3() {
+  takesAny(Deli.self) // expected-error {{argument type 'Deli<_>.Type' does not conform to expected type 'Any' (aka 'protocol<>')}}
+}