diff --git a/include/boost/config/compiler/clang.hpp b/include/boost/config/compiler/clang.hpp
index 6cc8b22f..47ea65b0 100644
--- a/include/boost/config/compiler/clang.hpp
+++ b/include/boost/config/compiler/clang.hpp
@@ -189,7 +189,7 @@
 #  define BOOST_NO_CXX11_USER_DEFINED_LITERALS
 #endif
 
-#if !(__has_feature(cxx_alignas) || __has_extension(cxx_alignas))
+#if !__has_feature(cxx_alignas)
 #  define BOOST_NO_CXX11_ALIGNAS
 #endif
 
@@ -209,11 +209,11 @@
 #  define BOOST_NO_CXX14_BINARY_LITERALS
 #endif
 
-#if !(__has_feature(__cxx_decltype_auto__) || __has_extension(__cxx_decltype_auto__))
+#if !__has_feature(__cxx_decltype_auto__)
 #  define BOOST_NO_CXX14_DECLTYPE_AUTO
 #endif
 
-#if !(__has_feature(__cxx_aggregate_nsdmi__) || __has_extension(__cxx_aggregate_nsdmi__))
+#if !__has_feature(__cxx_aggregate_nsdmi__)
 #  define BOOST_NO_CXX14_AGGREGATE_NSDMI
 #endif
 
@@ -221,7 +221,7 @@
 #  define BOOST_NO_CXX14_INITIALIZED_LAMBDA_CAPTURES
 #endif
 
-#if !(__has_feature(__cxx_generic_lambdas__) || __has_extension(__cxx_generic_lambdas__))
+#if !__has_feature(__cxx_generic_lambdas__)
 #  define BOOST_NO_CXX14_GENERIC_LAMBDAS
 #endif
 
@@ -239,12 +239,11 @@
 // so instead verify that we have a feature that was introduced at the same time as working C++14
 // constexpr (generic lambda's in this case):
 //
-#if !__has_feature(__cxx_generic_lambdas__) \
-  || !(__has_feature(__cxx_relaxed_constexpr__) || __has_extension(__cxx_relaxed_constexpr__))
+#if !__has_feature(__cxx_generic_lambdas__) || !__has_feature(__cxx_relaxed_constexpr__)
 #  define BOOST_NO_CXX14_CONSTEXPR
 #endif
 
-#if !(__has_feature(__cxx_return_type_deduction__) || __has_extension(__cxx_return_type_deduction__))
+#if !__has_feature(__cxx_return_type_deduction__)
 #  define BOOST_NO_CXX14_RETURN_TYPE_DEDUCTION
 #endif