diff --git a/lib/Sema/CSSimplify.cpp b/lib/Sema/CSSimplify.cpp
index 8822ed2ae90..4c6963bdcf6 100644
--- a/lib/Sema/CSSimplify.cpp
+++ b/lib/Sema/CSSimplify.cpp
@@ -2040,9 +2040,14 @@ commit_to_conversions:
       conversionsOrFixes.push_back(Fix::getForcedDowncast(*this, type2));
     }
 
+    // Look through IUO's.
+    auto type1WithoutIUO = objectType1;
+    if (auto elt = type1WithoutIUO->getImplicitlyUnwrappedOptionalObjectType())
+      type1WithoutIUO = elt;
+
     // If we could perform a bridging cast, try it.
     if (isArrayDictionarySetOrString(TC.Context, type2) &&
-        TC.getDynamicBridgedThroughObjCClass(DC, true, objectType1, type2)) {
+        TC.getDynamicBridgedThroughObjCClass(DC, true, type1WithoutIUO, type2)){
       conversionsOrFixes.push_back(Fix::getForcedDowncast(*this, type2));
     }
 
diff --git a/test/Constraints/bridging.swift b/test/Constraints/bridging.swift
index c3f3ecffdf3..7474d905b0b 100644
--- a/test/Constraints/bridging.swift
+++ b/test/Constraints/bridging.swift
@@ -275,3 +275,9 @@ func rdar19813772(nsma: NSMutableArray) {
 func force_cast_fixit(a : [NSString]) -> [NSString] {
   return a as! [NSString] // expected-warning {{forced cast of '[NSString]' to same type has no effect}} {{12-27=}}
 }
+
+// <rdar://problem/21244068> QoI: IUO prevents specific diagnostic + fixit about non-implicitly converted bridge types
+func rdar21244068(n: NSString!) -> String {
+  return n  // expected-error {{'NSString!' is not implicitly convertible to 'String'; did you mean to use 'as' to explicitly convert?}} {{11-11= as String}}
+}
+