build fix for pedantic compilers

src/server/game/Chat/ChatCommands/ChatCommand.h

@@ -45,8 +45,8 @@ struct CommandArgsConsumerSingle
 
 struct CommandArgsVariantConsumer
 {
-    template <typename V, typename T1, typename... Ts>
-    static std::enable_if_t<0 < sizeof...(Ts), char const*> TryConsumeTo(V& val, char const* args)
+    template <typename V, typename T1, typename T2, typename... Ts>
+    static char const* TryConsumeTo(V& val, char const* args)
     {
         T1 v;
         if (char const* next = CommandArgsConsumerSingle<T1>::TryConsumeTo(v, args))
@@ -55,7 +55,7 @@ struct CommandArgsVariantConsumer
             return next;
         }
         else
-            return TryConsumeTo<V, Ts...>(val, args);
+            return TryConsumeTo<V, T2, Ts...>(val, args);
     }
 
     template <typename V, typename T1>

src/server/game/Chat/ChatCommands/ChatCommandTags.h

@@ -52,23 +52,27 @@ struct ExactSequence : public ContainerTag
 {
     using value_type = void;
 
-    template <size_t U = sizeof...(chars)>
-    static typename std::enable_if_t<U, char const*> TryConsume(char const* pos)
+    static constexpr bool isSingleChar = !sizeof...(chars);
+
+    template <bool C = isSingleChar>
+    static typename std::enable_if_t<!C, char const*> _TryConsume(char const* pos)
     {
         if (*(pos++) == c1)
-            return ExactSequence<chars...>::TryConsume(pos);
+            return ExactSequence<chars...>::_TryConsume(pos);
         else
             return nullptr;
     }
 
-    template <size_t U = sizeof...(chars)>
-    static typename std::enable_if_t<!U, char const*> TryConsume(char const* pos)
+    template <bool C = isSingleChar>
+    static typename std::enable_if_t<C, char const*> _TryConsume(char const* pos)
     {
         if (*(pos++) != c1)
             return nullptr;
         // if more of string is left, tokenize should return 0 (otherwise we didn't reach end of token yet)
         return *pos && tokenize(pos) ? nullptr : pos;
     }
+
+    char const* TryConsume(char const* pos) const { return ExactSequence::_TryConsume(pos); }
 };
 
 /************************** VARIANT TAG LOGIC *********************************\