Work around requires support issue in GCC 10

Author: jarzec

regression-tests/mixed-type-safety-1.cpp2

@@ -10,8 +10,9 @@ class Square : public Shape { };
 
 //--- printing helpers -----------------
 
-print: <T : type> ( msg: std::string, x: T ) 
-       requires !std::convertible_to<T, bool> =
+non_bool: <T> concept = !std::convertible_to<T, bool>;
+
+print: <T : non_bool> ( msg: std::string, x: T ) =
     std::cout << msg << x << "\n";
 
 print: ( msg: std::string, b: bool ) =

regression-tests/test-results/gcc-10-c++20/mixed-type-safety-1.cpp.output

@@ -24,13 +24,14 @@ class Square : public Shape { };
 //--- printing helpers -----------------
 
 #line 13 "mixed-type-safety-1.cpp2"
-template<typename T> auto print(cpp2::impl::in<std::string> msg, T const& x) -> void
-CPP2_REQUIRES (!(std::convertible_to<T,bool>)) ;
+template<typename T> concept non_bool = !(std::convertible_to<T,bool>); 
 
-#line 17 "mixed-type-safety-1.cpp2"
+template<non_bool T> auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<T> x) -> void;
+
+#line 18 "mixed-type-safety-1.cpp2"
 auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void;
 
-#line 25 "mixed-type-safety-1.cpp2"
+#line 26 "mixed-type-safety-1.cpp2"
 //--- examples -------------------------
 
 [[nodiscard]] auto main() -> int;
@@ -39,14 +40,11 @@ auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void;
 
 #line 1 "mixed-type-safety-1.cpp2"
 
-#line 13 "mixed-type-safety-1.cpp2"
-template<typename T> auto print(cpp2::impl::in<std::string> msg, T const& x) -> void
-requires (!(std::convertible_to<T,bool>))  { 
-
 #line 15 "mixed-type-safety-1.cpp2"
+template<non_bool T> auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<T> x) -> void { 
     std::cout << msg << x << "\n";  }
 
-#line 17 "mixed-type-safety-1.cpp2"
+#line 18 "mixed-type-safety-1.cpp2"
 auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void
 {
     cpp2::impl::deferred_init<char const*> bmsg; 
@@ -55,7 +53,7 @@ auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void
     std::cout << msg << cpp2::move(bmsg.value()) << "\n";
 }
 
-#line 27 "mixed-type-safety-1.cpp2"
+#line 28 "mixed-type-safety-1.cpp2"
 [[nodiscard]] auto main() -> int
 {
     ::print("1.1 is int? ", cpp2::impl::is<int>(1.1));