From 44e4d1335a2e15fe7ce6852436259eb1138d44c4 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Mon, 29 Oct 2018 23:16:16 +0100
Subject: [PATCH] Fix Traits::IsSpecializationOf to ignore cv qualifier

So eg. const/volatile std::string is also considered a
specialization of std::basic_string like one would expect.
---
 misc/traits.h         | 12 +++++++++---
 tests/traitstests.cpp |  6 ++++--
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/misc/traits.h b/misc/traits.h
index f1aac92..04fc3ba 100644
--- a/misc/traits.h
+++ b/misc/traits.h
@@ -54,11 +54,17 @@ template <typename... Condition> using EnableIfAny = typename std::enable_if<Any
 /// \brief Shortcut for std::enable_if to apply Traits::Any, negate the condition and omit ::value and ::type.
 template <typename... Condition> using DisableIfAny = typename std::enable_if<!Any<Condition...>::value, Detail::Enabler>::type;
 
-/// \brief Evaluates to Bool<true> if the specified type is based on the specified \tparam Template; otherwise evaluates to Bool<false>.
-template <typename T, template <typename...> class Template> struct IsSpecializationOf : Bool<false> {
+/// \cond
+namespace Detail {
+template <typename T, template <typename...> class Template> struct IsSpecializationOfHelper : Bool<false> {
 };
+template <template <typename...> class Template, typename... Args> struct IsSpecializationOfHelper<Template<Args...>, Template> : Bool<true> {
+};
+} // namespace Detail
+/// \endcond
 /// \brief Evaluates to Bool<true> if the specified type is based on the specified \tparam Template; otherwise evaluates to Bool<false>.
-template <template <typename...> class Template, typename... Args> struct IsSpecializationOf<Template<Args...>, Template> : Bool<true> {
+template <typename Type, template <typename...> class... TemplateTypes>
+struct IsSpecializationOf : Detail::IsSpecializationOfHelper<typename std::remove_cv<Type>::type, TemplateTypes...> {
 };
 /// \brief Evaluates to Bool<true> if the specified type is based on one of the specified templates; otherwise evaluates to Bool<false>.
 template <typename Type, template <typename...> class... TemplateTypes> struct IsSpecializingAnyOf : Bool<false> {
diff --git a/tests/traitstests.cpp b/tests/traitstests.cpp
index aca6c6e..eb71a39 100644
--- a/tests/traitstests.cpp
+++ b/tests/traitstests.cpp
@@ -90,8 +90,10 @@ static_assert(IsCString<const char *>::value, "IsCString: positive case");
 static_assert(!IsString<int *>::value, "IsString: negative case");
 static_assert(!IsString<stringstream>::value, "IsString: negative case");
 static_assert(IsString<const char *>::value, "IsString: positive case");
-static_assert(IsString<string>::value, "IsCString: positive case");
-static_assert(IsString<u16string>::value, "IsCString: positive case");
+static_assert(IsString<string>::value, "IsString: positive case");
+static_assert(IsString<const string>::value, "IsString: positive case (const)");
+static_assert(IsString<volatile string>::value, "IsString: positive case (volatile)");
+static_assert(IsString<u16string>::value, "IsString: positive case");
 
 static_assert(!IsComplete<TestIncomplete>::value, "IsComplete: negative case");
 static_assert(IsComplete<CountableStruct>::value, "IsComplete: positive case");