--- gcc/c-family/c-lex.c.jj	2018-10-08 15:18:36.665860856 +0200
+++ gcc/c-family/c-lex.c	2018-10-10 15:48:46.180923864 +0200
@@ -357,7 +357,7 @@ c_common_has_attribute (cpp_reader *pfil
 		       || is_attribute_p ("fallthrough", attr_name))
 		result = 201603;
 	      else if (is_attribute_p ("no_unique_address", attr_name))
-		result = 20180312;
+		result = 201803;
 	      if (result)
 		attr_name = NULL_TREE;
 	    }
--- gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C.jj	2018-10-10 15:52:00.896663247 +0200
+++ gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C	2018-10-10 15:52:59.865675782 +0200
@@ -0,0 +1,447 @@
+// { dg-options "-std=c++2a -I${srcdir}/g++.dg/cpp1y -I${srcdir}/g++.dg/cpp1y/testinc" }
+
+//  C++98 features:
+
+#ifndef __cpp_rtti
+#  error "__cpp_rtti"
+#elif  __cpp_rtti != 199711
+#  error "__cpp_rtti != 199711"
+#endif
+
+#ifndef __cpp_exceptions
+#  error "__cpp_exceptions"
+#elif  __cpp_exceptions != 199711
+#  error "__cpp_exceptions != 199711"
+#endif
+
+//  C++11 features:
+
+#ifndef __cpp_raw_strings
+#  error "__cpp_raw_strings"
+#elif __cpp_raw_strings != 200710
+#  error "__cpp_raw_strings != 200710"
+#endif
+
+#ifndef __cpp_unicode_literals
+#  error "__cpp_unicode_literals"
+#elif __cpp_unicode_literals != 200710
+#  error "__cpp_unicode_literals != 200710"
+#endif
+
+#ifndef __cpp_user_defined_literals
+#  error "__cpp_user_defined_literals"
+#elif __cpp_user_defined_literals != 200809
+#  error "__cpp_user_defined_literals != 200809"
+#endif
+
+#ifndef __cpp_lambdas
+#  error "__cpp_lambdas"
+#elif __cpp_lambdas != 200907
+#  error "__cpp_lambdas != 200907"
+#endif
+
+#ifndef __cpp_range_based_for
+#  error "__cpp_range_based_for"
+#elif __cpp_range_based_for != 201603
+#  error "__cpp_range_based_for != 201603"
+#endif
+
+#ifndef __cpp_decltype
+#  error "__cpp_decltype"
+#elif __cpp_decltype != 200707
+#  error "__cpp_decltype != 200707"
+#endif
+
+#ifndef __cpp_attributes
+#  error "__cpp_attributes"
+#elif __cpp_attributes != 200809
+#  error "__cpp_attributes != 200809"
+#endif
+
+#ifndef __cpp_rvalue_references
+#  error "__cpp_rvalue_references"
+#elif __cpp_rvalue_references != 200610
+#  error "__cpp_rvalue_references != 200610"
+#endif
+
+#ifndef __cpp_variadic_templates
+#  error "__cpp_variadic_templates"
+#elif __cpp_variadic_templates != 200704
+#  error "__cpp_variadic_templates != 200704"
+#endif
+
+#ifndef __cpp_initializer_lists
+#  error "__cpp_initializer_lists"
+#elif __cpp_initializer_lists != 200806
+#  error "__cpp_initializer_lists != 200806"
+#endif
+
+#ifndef __cpp_delegating_constructors
+#  error "__cpp_delegating_constructors"
+#elif __cpp_delegating_constructors != 200604
+#  error "__cpp_delegating_constructors != 200604"
+#endif
+
+#ifndef __cpp_nsdmi
+#  error "__cpp_nsdmi"
+#elif __cpp_nsdmi != 200809
+#  error "__cpp_nsdmi != 200809"
+#endif
+
+#ifndef __cpp_inheriting_constructors
+#  error "__cpp_inheriting_constructors"
+#elif  __cpp_inheriting_constructors!= 201511
+#  error "__cpp_inheriting_constructors != 201511"
+#endif
+
+#ifndef __cpp_ref_qualifiers
+#  error "__cpp_ref_qualifiers"
+#elif __cpp_ref_qualifiers != 200710
+#  error "__cpp_ref_qualifiers != 200710"
+#endif
+
+#ifndef __cpp_alias_templates
+#  error "__cpp_alias_templates"
+#elif __cpp_alias_templates != 200704
+#  error "__cpp_alias_templates != 200704"
+#endif
+
+#ifndef __cpp_threadsafe_static_init
+#  error "__cpp_threadsafe_static_init"
+#elif __cpp_threadsafe_static_init != 200806
+#  error "__cpp_threadsafe_static_init != 200806"
+#endif
+
+//  C++14 features:
+
+#ifndef __cpp_binary_literals
+#  error "__cpp_binary_literals"
+#elif __cpp_binary_literals != 201304
+#  error "__cpp_binary_literals != 201304"
+#endif
+
+#ifndef __cpp_init_captures
+#  error "__cpp_init_captures"
+#elif __cpp_init_captures != 201304
+#  error "__cpp_init_captures != 201304"
+#endif
+
+#ifndef __cpp_generic_lambdas
+#  error "__cpp_generic_lambdas"
+#elif __cpp_generic_lambdas != 201304
+#  error "__cpp_generic_lambdas != 201304"
+#endif
+
+#ifndef __cpp_constexpr
+#  error "__cpp_constexpr"
+#elif __cpp_constexpr != 201603
+#  error "__cpp_constexpr != 201603"
+#endif
+
+#ifndef __cpp_decltype_auto
+#  error "__cpp_decltype_auto"
+#elif __cpp_decltype_auto != 201304
+#  error "__cpp_decltype_auto != 201304"
+#endif
+
+#ifndef __cpp_return_type_deduction
+#  error "__cpp_return_type_deduction"
+#elif __cpp_return_type_deduction != 201304
+#  error "__cpp_return_type_deduction != 201304"
+#endif
+
+#ifndef __cpp_aggregate_nsdmi
+#  error "__cpp_aggregate_nsdmi"
+#elif __cpp_aggregate_nsdmi != 201304
+#  error "__cpp_aggregate_nsdmi != 201304"
+#endif
+
+#ifndef __cpp_variable_templates
+#  error "__cpp_variable_templates"
+#elif __cpp_variable_templates != 201304
+#  error "__cpp_variable_templates != 201304"
+#endif
+
+#ifndef __cpp_digit_separators
+#  error "__cpp_digit_separators"
+#elif __cpp_digit_separators != 201309
+#  error "__cpp_digit_separators != 201309"
+#endif
+
+#ifndef __cpp_sized_deallocation
+#  error "__cpp_sized_deallocation"
+#elif __cpp_sized_deallocation != 201309
+#  error "__cpp_sized_deallocation != 201309"
+#endif
+
+//  GNU VLA support:
+
+#ifndef __cpp_runtime_arrays
+#  error "__cpp_runtime_arrays"
+#elif __cpp_runtime_arrays != 198712
+#  error "__cpp_runtime_arrays != 198712"
+#endif
+
+//  C++11 attributes:
+
+#ifdef __has_cpp_attribute
+#  if ! __has_cpp_attribute(noreturn)
+#    error "__has_cpp_attribute(noreturn)"
+#  elif __has_cpp_attribute(noreturn) != 200809
+#    error "__has_cpp_attribute(noreturn) != 200809"
+#  endif
+#else
+#  error "__has_cpp_attribute"
+#endif
+
+//  Attribute carries_dependency not in yet.
+//#ifdef __has_cpp_attribute
+//#  if ! __has_cpp_attribute(carries_dependency)
+//#    error "__has_cpp_attribute(carries_dependency)"
+//#  elif __has_cpp_attribute(carries_dependency) != 200809
+//#    error "__has_cpp_attribute(carries_dependency) != 200809"
+//#  endif
+//#else
+//#  error "__has_cpp_attribute"
+//#endif
+
+//  C++14 attributes:
+
+#ifdef __has_cpp_attribute
+#  if ! __has_cpp_attribute(deprecated)
+#    error "__has_cpp_attribute(deprecated)"
+#  elif __has_cpp_attribute(deprecated) != 201309
+#    error "__has_cpp_attribute(deprecated) != 201309"
+#  endif
+#else
+#  error "__has_cpp_attribute"
+#endif
+
+//  Include checks:
+
+//  Check for __has_include macro.
+#ifndef __has_include
+#  error "__has_include"
+#endif
+
+//  Quoted complex.h should find at least the bracket version (use operator).
+#if __has_include__ "complex.h"
+#else
+#  error "complex.h"
+#endif
+
+//  Try known bracket header (use operator).
+#if __has_include__(<complex>)
+#else
+#  error "<complex>"
+#endif
+
+//  Define and use a macro to invoke the operator.
+#define sluggo(TXT) __has_include__(TXT)
+
+#if sluggo(<complex>)
+#else
+#  error "<complex>"
+#endif
+
+#if ! sluggo(<complex>)
+#  error "<complex>"
+#else
+#endif
+
+//  Quoted complex.h should find at least the bracket version.
+#if __has_include("complex.h")
+#else
+#  error "complex.h"
+#endif
+
+//  Try known local quote header.
+#if __has_include("complex_literals.h")
+#else
+#  error "\"complex_literals.h\""
+#endif
+
+//  Try nonexistent bracket header.
+#if __has_include(<stuff>)
+#  error "<stuff>"
+#else
+#endif
+
+//  Try nonexistent quote header.
+#if __has_include("phlegm")
+#  error "\"phlegm\""
+#else
+#endif
+
+//  Test __has_include_next.
+#if __has_include("phoobhar.h")
+#  include "phoobhar.h"
+#else
+#  error "__has_include(\"phoobhar.h\")"
+#endif
+
+//  Try a macro.
+#define COMPLEX_INC "complex.h"
+#if __has_include(COMPLEX_INC)
+#else
+#  error COMPLEX_INC
+#endif
+
+//  Realistic use of __has_include.
+#if __has_include(<array>)
+#  define STD_ARRAY 1
+#  include <array>
+  template<typename _Tp, size_t _Num>
+    using array = std::array<_Tp, _Num>;
+#elif __has_include(<tr1/array>)
+#  define TR1_ARRAY 1
+#  include <tr1/array>
+  template<typename _Tp, size_t _Num>
+    typedef std::tr1::array<_Tp, _Num> array;
+#endif
+
+// C++17 features:
+
+#ifndef __cpp_unicode_characters
+#  error "__cpp_unicode_characters"
+#elif __cpp_unicode_characters != 201411
+#  error "__cpp_unicode_characters != 201411"
+#endif
+
+#ifndef __cpp_static_assert
+#  error "__cpp_static_assert"
+#elif __cpp_static_assert != 201411
+#  error "__cpp_static_assert != 201411"
+#endif
+
+#ifndef __cpp_namespace_attributes
+#  error "__cpp_namespace_attributes"
+#elif __cpp_namespace_attributes != 201411
+#  error "__cpp_namespace_attributes != 201411"
+#endif
+
+#ifndef __cpp_enumerator_attributes
+#  error "__cpp_enumerator_attributes"
+#elif __cpp_enumerator_attributes != 201411
+#  error "__cpp_enumerator_attributes != 201411"
+#endif
+
+#ifndef __cpp_nested_namespace_definitions
+#  error "__cpp_nested_namespace_definitions"
+#elif __cpp_nested_namespace_definitions != 201411
+#  error "__cpp_nested_namespace_definitions != 201411"
+#endif
+
+#ifndef __cpp_fold_expressions
+#  error "__cpp_fold_expressions"
+#elif __cpp_fold_expressions != 201603
+#  error "__cpp_fold_expressions != 201603"
+#endif
+
+#ifndef __cpp_nontype_template_args
+#  error "__cpp_nontype_template_args"
+#elif __cpp_nontype_template_args != 201411
+#  error "__cpp_nontype_template_args != 201411"
+#endif
+
+#ifndef __cpp_hex_float
+#  error "__cpp_hex_float"
+#elif __cpp_hex_float != 201603
+#  error "__cpp_hex_float != 201603"
+#endif
+
+#ifndef __cpp_aggregate_bases
+#  error "__cpp_aggregate_bases"
+#elif __cpp_aggregate_bases != 201603
+#  error "__cpp_aggregate_bases != 201603"
+#endif
+
+#ifndef __cpp_deduction_guides
+#  error "__cpp_deduction_guides"
+#elif __cpp_deduction_guides != 201703
+#  error "__cpp_deduction_guides != 201703"
+#endif
+
+#ifndef __cpp_if_constexpr
+#  error "__cpp_if_constexpr"
+#elif __cpp_if_constexpr != 201606
+#  error "__cpp_if_constexpr != 201606"
+#endif
+
+#ifndef __cpp_aligned_new
+#  error "__cpp_aligned_new"
+#elif __cpp_aligned_new != 201606
+#  error "__cpp_aligned_new != 201606"
+#endif
+
+#ifndef __cpp_template_auto
+#  error "__cpp_template_auto"
+#elif __cpp_template_auto != 201606
+#  error "__cpp_template_auto != 201606"
+#endif
+
+#ifndef __cpp_inline_variables
+#  error "__cpp_inline_variables"
+#elif __cpp_inline_variables != 201606
+#  error "__cpp_inline_variables != 201606"
+#endif
+
+#ifndef __cpp_capture_star_this
+#  error "__cpp_capture_star_this"
+#elif __cpp_capture_star_this != 201603
+#  error "__cpp_capture_star_this != 201603"
+#endif
+
+#ifndef __cpp_noexcept_function_type
+#  error "__cpp_noexcept_function_type"
+#elif __cpp_noexcept_function_type != 201510
+#  error "__cpp_noexcept_function_type != 201510"
+#endif
+
+#ifndef __cpp_structured_bindings
+#  error "__cpp_structured_bindings"
+#elif __cpp_structured_bindings != 201606
+#  error "__cpp_structured_bindings != 201606"
+#endif
+
+#ifndef __cpp_template_template_args
+#  error "__cpp_template_template_args"
+#elif __cpp_template_template_args != 201611
+#  error "__cpp_template_template_args != 201611"
+#endif
+
+#ifndef __cpp_variadic_using
+#  error "__cpp_variadic_using"
+#elif __cpp_variadic_using != 201611
+#  error "__cpp_variadic_using != 201611"
+#endif
+
+#ifdef __has_cpp_attribute
+
+#  if ! __has_cpp_attribute(maybe_unused)
+#    error "__has_cpp_attribute(maybe_unused)"
+#  elif __has_cpp_attribute(maybe_unused) != 201603
+#    error "__has_cpp_attribute(maybe_unused) != 201603"
+#  endif
+
+#  if ! __has_cpp_attribute(nodiscard)
+#    error "__has_cpp_attribute(nodiscard)"
+#  elif __has_cpp_attribute(nodiscard) != 201603
+#    error "__has_cpp_attribute(nodiscard) != 201603"
+#  endif
+
+#  if ! __has_cpp_attribute(fallthrough)
+#    error "__has_cpp_attribute(fallthrough)"
+#  elif __has_cpp_attribute(fallthrough) != 201603
+#    error "__has_cpp_attribute(fallthrough) != 201603"
+#  endif
+
+#  if ! __has_cpp_attribute(no_unique_address)
+#    error "__has_cpp_attribute(no_unique_address)"
+#  elif __has_cpp_attribute(no_unique_address) != 201803
+#    error "__has_cpp_attribute(no_unique_address) != 201803"
+#  endif
+
+#else
+#  error "__has_cpp_attribute"
+#endif
