diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
index 29b7d107a5976..86a80bceb2d8e 100644
--- a/lib/ClangImporter/ClangImporter.cpp
+++ b/lib/ClangImporter/ClangImporter.cpp
@@ -323,11 +323,7 @@ void ClangImporter::clearTypeResolver() {
 
 #pragma mark Module loading
 
-#ifdef NDEBUG
 #define SHIMS_INCLUDE_FLAG "-isystem"
-#else
-#define SHIMS_INCLUDE_FLAG "-I"
-#endif
 
 static StringRef
 getMinVersionOptNameForDarwinTriple(const llvm::Triple &triple) {
diff --git a/stdlib/public/SDK/Foundation/Data.swift b/stdlib/public/SDK/Foundation/Data.swift
index 6cdb3ec661d8e..49636cb7c2aa5 100644
--- a/stdlib/public/SDK/Foundation/Data.swift
+++ b/stdlib/public/SDK/Foundation/Data.swift
@@ -875,11 +875,11 @@ public struct Data : ReferenceConvertible, Equatable, Hashable, RandomAccessColl
 #else
             switch self {
             case .virtualMemory:
-                return { NSDataDeallocatorVM($0, UInt($1)) }
+                return { NSDataDeallocatorVM($0, $1) }
             case .unmap:
-                return { NSDataDeallocatorUnmap($0, UInt($1)) }
+                return { NSDataDeallocatorUnmap($0, $1) }
             case .free:
-                return { NSDataDeallocatorFree($0, UInt($1)) }
+                return { NSDataDeallocatorFree($0, $1) }
             case .none:
                 return { _, _ in }
             case .custom(let b):
diff --git a/stdlib/public/SDK/Foundation/IndexSet.swift b/stdlib/public/SDK/Foundation/IndexSet.swift
index 1c2818bf9e58f..6ceed0f4fc6fe 100644
--- a/stdlib/public/SDK/Foundation/IndexSet.swift
+++ b/stdlib/public/SDK/Foundation/IndexSet.swift
@@ -258,9 +258,9 @@ public struct IndexSet : ReferenceConvertible, Equatable, BidirectionalCollectio
     
     private func _indexOfRange(containing integer : Element) -> RangeView.Index? {
         let result = _handle.map { 
-            __NSIndexSetIndexOfRangeContainingIndex($0, UInt(integer))
+            __NSIndexSetIndexOfRangeContainingIndex($0, integer)
         }
-        if result == UInt(NSNotFound) {
+        if result == NSNotFound {
             return nil
         } else {
             return Int(result)
@@ -269,9 +269,9 @@ public struct IndexSet : ReferenceConvertible, Equatable, BidirectionalCollectio
     
     private func _range(at index: RangeView.Index) -> Range<Element> {
         return _handle.map {
-            var location: UInt = 0
-            var length: UInt = 0
-            __NSIndexSetRangeAtIndex($0, UInt(index), &location, &length)
+            var location: Int = 0
+            var length: Int = 0
+            __NSIndexSetRangeAtIndex($0, index, &location, &length)
             return Int(location)..<Int(location)+Int(length)
         }
     }
diff --git a/stdlib/public/SDK/Foundation/NSDictionary.swift b/stdlib/public/SDK/Foundation/NSDictionary.swift
index 2ba57a50e0d71..7ef6507977733 100644
--- a/stdlib/public/SDK/Foundation/NSDictionary.swift
+++ b/stdlib/public/SDK/Foundation/NSDictionary.swift
@@ -233,7 +233,7 @@ extension NSDictionary {
     let valueBuffer = buffer.bindMemory(to: AnyObject.self, capacity: numElems)
     let buffer2 = buffer + singleSize
 
-    __NSDictionaryGetObjects(otherDictionary, buffer, buffer2, UInt(numElems))
+    __NSDictionaryGetObjects(otherDictionary, buffer, buffer2, numElems)
 
     let keyBufferCopying = buffer2.assumingMemoryBound(to: NSCopying.self)
     self.init(objects: valueBuffer, forKeys: keyBufferCopying, count: numElems)