diff --git a/src/catch2/internal/catch_clara.hpp b/src/catch2/internal/catch_clara.hpp
index d869593b..85874a15 100644
--- a/src/catch2/internal/catch_clara.hpp
+++ b/src/catch2/internal/catch_clara.hpp
@@ -66,15 +66,13 @@ namespace Catch {
             };
 
             template <typename F, typename = void>
-            struct is_unary_function : std::false_type {};
+            static constexpr bool is_unary_function_v = false;
 
             template <typename F>
-            struct is_unary_function<
+            static constexpr bool is_unary_function_v<
                 F,
-                Catch::Detail::void_t<decltype(
-                    std::declval<F>()( fake_arg() ) )
-                >
-            > : std::true_type {};
+                Catch::Detail::void_t<decltype( std::declval<F>()(
+                    fake_arg() ) )>> = true;
 
             // Traits for extracting arg and return type of lambdas (for single
             // argument lambdas)
@@ -507,14 +505,14 @@ namespace Catch {
 
                 template <typename T,
                           typename = typename std::enable_if_t<
-                              !Detail::is_unary_function<T>::value>>
+                              !Detail::is_unary_function_v<T>>>
                 ParserRefImpl( T& ref, StringRef hint ):
                     m_ref( std::make_shared<BoundValueRef<T>>( ref ) ),
                     m_hint( hint ) {}
 
                 template <typename LambdaT,
                           typename = typename std::enable_if_t<
-                              Detail::is_unary_function<LambdaT>::value>>
+                              Detail::is_unary_function_v<LambdaT>>>
                 ParserRefImpl( LambdaT const& ref, StringRef hint ):
                     m_ref( std::make_shared<BoundLambda<LambdaT>>( ref ) ),
                     m_hint( hint ) {}
@@ -581,7 +579,7 @@ namespace Catch {
 
             template <typename LambdaT,
                       typename = typename std::enable_if_t<
-                          Detail::is_unary_function<LambdaT>::value>>
+                          Detail::is_unary_function_v<LambdaT>>>
             Opt( LambdaT const& ref, StringRef hint ):
                 ParserRefImpl( ref, hint ) {}
 
@@ -591,7 +589,7 @@ namespace Catch {
 
             template <typename T,
                       typename = typename std::enable_if_t<
-                          !Detail::is_unary_function<T>::value>>
+                          !Detail::is_unary_function_v<T>>>
             Opt( T& ref, StringRef hint ):
                 ParserRefImpl( ref, hint ) {}
 
diff --git a/tests/SelfTest/Baselines/compact.sw.approved.txt b/tests/SelfTest/Baselines/compact.sw.approved.txt
index 50f09b1b..840d3dcb 100644
--- a/tests/SelfTest/Baselines/compact.sw.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.approved.txt
@@ -2534,18 +2534,18 @@ Skip.tests.cpp:<line number>: skipped:
 Skip.tests.cpp:<line number>: skipped:
 Skip.tests.cpp:<line number>: failed: explicitly
 loose text artifact
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<int>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<std::string const&>::value)'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<int>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<std::string const&>)'
 Message.tests.cpp:<line number>: failed: explicitly with 1 message: 'Previous info should not be seen'
 Message.tests.cpp:<line number>: failed: explicitly with 1 message: 'previous unscoped info SHOULD not be seen'
 Misc.tests.cpp:<line number>: passed: l == std::numeric_limits<long long>::max() for: 9223372036854775807 (0x<hex digits>)
diff --git a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
index 7e5535ba..933a887a 100644
--- a/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/compact.sw.multi.approved.txt
@@ -2526,18 +2526,18 @@ Skip.tests.cpp:<line number>: failed: explicitly
 Skip.tests.cpp:<line number>: skipped:
 Skip.tests.cpp:<line number>: skipped:
 Skip.tests.cpp:<line number>: failed: explicitly
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<int>::value)'
-Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function<std::string const&>::value)'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<int>)'
+Clara.tests.cpp:<line number>: passed: with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<std::string const&>)'
 Message.tests.cpp:<line number>: failed: explicitly with 1 message: 'Previous info should not be seen'
 Message.tests.cpp:<line number>: failed: explicitly with 1 message: 'previous unscoped info SHOULD not be seen'
 Misc.tests.cpp:<line number>: passed: l == std::numeric_limits<long long>::max() for: 9223372036854775807 (0x<hex digits>)
diff --git a/tests/SelfTest/Baselines/console.sw.approved.txt b/tests/SelfTest/Baselines/console.sw.approved.txt
index 9e4e0e16..414a8881 100644
--- a/tests/SelfTest/Baselines/console.sw.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.approved.txt
@@ -16704,51 +16704,51 @@ Clara.tests.cpp:<line number>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<int>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<int>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<std::string const&>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<std::string const&>)
 
 -------------------------------------------------------------------------------
 just failure
diff --git a/tests/SelfTest/Baselines/console.sw.multi.approved.txt b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
index 84205756..cb13b0ff 100644
--- a/tests/SelfTest/Baselines/console.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/console.sw.multi.approved.txt
@@ -16696,51 +16696,51 @@ Clara.tests.cpp:<line number>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value
+  Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<int>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<int>)
 
 Clara.tests.cpp:<line number>: PASSED:
 with message:
-  !(Catch::Clara::Detail::is_unary_function<std::string const&>::value)
+  !(Catch::Clara::Detail::is_unary_function_v<std::string const&>)
 
 -------------------------------------------------------------------------------
 just failure
diff --git a/tests/SelfTest/Baselines/tap.sw.approved.txt b/tests/SelfTest/Baselines/tap.sw.approved.txt
index 59247a9c..f1064e6b 100644
--- a/tests/SelfTest/Baselines/tap.sw.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.approved.txt
@@ -4019,29 +4019,29 @@ ok {test-number} -  # SKIP
 not ok {test-number} - explicitly
 loose text artifact
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<int>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<int>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<std::string const&>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<std::string const&>)'
 # just failure
 not ok {test-number} - explicitly with 1 message: 'Previous info should not be seen'
 # just failure after unscoped info
diff --git a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
index eba0bd3a..bdfc9c3b 100644
--- a/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
+++ b/tests/SelfTest/Baselines/tap.sw.multi.approved.txt
@@ -4011,29 +4011,29 @@ ok {test-number} -  # SKIP
 # failing in some unskipped sections causes entire test case to fail
 not ok {test-number} - explicitly
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>'
 # is_unary_function
-ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value'
+ok {test-number} - with 1 message: 'Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<int>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<int>)'
 # is_unary_function
-ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function<std::string const&>::value)'
+ok {test-number} - with 1 message: '!(Catch::Clara::Detail::is_unary_function_v<std::string const&>)'
 # just failure
 not ok {test-number} - explicitly with 1 message: 'Previous info should not be seen'
 # just failure after unscoped info
diff --git a/tests/SelfTest/IntrospectiveTests/Clara.tests.cpp b/tests/SelfTest/IntrospectiveTests/Clara.tests.cpp
index 53023b50..0fadad6d 100644
--- a/tests/SelfTest/IntrospectiveTests/Clara.tests.cpp
+++ b/tests/SelfTest/IntrospectiveTests/Clara.tests.cpp
@@ -25,19 +25,19 @@ TEST_CASE("is_unary_function", "[clara][compilation]") {
     auto nullary1 = []() {};
     auto nullary2 = []() {return 42;};
 
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary1)>::value);
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary2)>::value);
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary3)>::value);
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary4)>::value);
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary5)>::value);
-    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function<decltype(unary6)>::value);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary1)>);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary2)>);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary3)>);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary4)>);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary5)>);
+    STATIC_REQUIRE(Catch::Clara::Detail::is_unary_function_v<decltype(unary6)>);
 
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<decltype(binary1)>::value);
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<decltype(binary2)>::value);
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<decltype(nullary1)>::value);
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<decltype(nullary2)>::value);
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<int>::value);
-    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function<std::string const&>::value);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<decltype(binary1)>);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<decltype(binary2)>);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<decltype(nullary1)>);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<decltype(nullary2)>);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<int>);
+    STATIC_REQUIRE_FALSE(Catch::Clara::Detail::is_unary_function_v<std::string const&>);
 }