diff --git a/stdlib/public/runtime/HeapObject.cpp b/stdlib/public/runtime/HeapObject.cpp
index ab1dbeaebee..fc238579e33 100644
--- a/stdlib/public/runtime/HeapObject.cpp
+++ b/stdlib/public/runtime/HeapObject.cpp
@@ -58,11 +58,6 @@ using namespace swift;
 #error "The runtime must be built with a compiler that supports swiftcall."
 #endif
 
-// Check that the user isn't manually disabling SWIFTCALL.
-#if defined(SWIFT_USE_SWIFTCALL) && !SWIFT_USE_SWIFTCALL
-#error "SWIFT_USE_SWIFTCALL=0 is not supported; swiftcall must always be used."
-#endif
-
 /// Returns true if the pointer passed to a native retain or release is valid.
 /// If false, the operation should immediately return.
 static inline bool isValidPointerForNativeRetain(const void *p) {