[type_traits] add concepts

Author: iboB

include/itlib/type_traits.hpp

@@ -28,7 +28,7 @@
 //
 //                  VERSION HISTORY
 //
-//  1.03 (2025-12-15) Add copy_cv
+//  1.03 (2025-12-15) Add copy_cv, add concepts
 //  1.02 (2023-11-27) Added is_noop_convertible
 //  1.01 (2023-03-10) Added type_identity
 //  1.00 (2020-12-28) First pulic release
@@ -112,4 +112,12 @@ template <typename To, typename From>
 using copy_cv_t = typename copy_cv<To, From>::type;
 #endif
 
+#if __cplusplus >= 202000
+template <typename Type, template <typename...> class Template>
+concept instantiation_of = is_instantiation_of_v<Template, Type>;
+
+template <typename From, typename To>
+concept noop_convertible_to = is_noop_convertible_v<From, To>;
+#endif
+
 }

test/t-type_traits-17.cpp

@@ -64,4 +64,4 @@ TEST_CASE("copy_cv") {
     CCHECK(std::is_same_v<T3, volatile long>);
     using T4 = itlib::copy_cv_t<unsigned short, const short>;
     CCHECK(std::is_same_v<T4, const unsigned short>);
-}
+}

test/t-type_traits-20.cpp

@@ -0,0 +1,39 @@
+// Copyright (c) Borislav Stanimirov
+// SPDX-License-Identifier: MIT
+//
+#include <itlib/type_traits.hpp>
+#include <doctest/doctest.h>
+#include <vector>
+#include <string>
+
+template <itlib::instantiation_of<std::vector> T>
+int test_instantiation_of(T&) {
+    return 42;
+}
+
+template <itlib::instantiation_of<std::basic_string> T>
+int test_instantiation_of(T&) {
+    return 24;
+}
+
+TEST_CASE("instantiation_of concept") {
+    std::string s;
+    CHECK(test_instantiation_of(s) == 24);
+    std::vector<int> v;
+    CHECK(test_instantiation_of(v) == 42);
+}
+
+template <itlib::noop_convertible_to<int> T>
+int test_noop_convertible(T) {
+    return 7;
+}
+
+template <itlib::noop_convertible_to<void*> T>
+int test_noop_convertible(T) {
+    return 14;
+}
+
+TEST_CASE("noop_convertible_to concept") {
+    CHECK(test_noop_convertible(5) == 7);
+    CHECK(test_noop_convertible(size_t(32)) == 14);
+}