[QoI] Ignore incorrect parameter types when trying to diagnose trailing closures

Resolves: rdar://problem/28004686

Author: xedin

lib/Sema/CSDiag.cpp

@@ -6116,7 +6116,7 @@ bool FailureDiagnosis::diagnoseTrailingClosureErrors(ApplyExpr *callExpr) {
     case TypeKind::Tuple: {
       auto tuple = paramType->getAs<TupleType>();
       if (tuple->getNumElements() != 1)
-        return false;
+        continue;
 
       paramType = tuple->getElement(0).getType();
       break;

test/Constraints/trailing_closures_objc.swift

@@ -13,3 +13,8 @@ func foo(options: [AVMediaSelectionOption]) {
     // expected-error@-1 {{type 'NSViewController' has no member 'respondToMediaOptionSelection(from:)'}}
   }
 }
+
+func rdar28004686(a: [IndexPath]) {
+  _ = a.sorted { (lhs: NSIndexPath, rhs: NSIndexPath) -> Bool in true }
+  // expected-error@-1 {{'NSIndexPath' is not convertible to 'IndexPath'}}
+}