Add fix for is any and a regression test, closes #5

Author: hsutter

include/cpp2util.h

@@ -615,12 +615,12 @@ auto as( std::variant<Ts...> const& x ) {
 //  std::any is and as
 //
 template<typename T, typename X>
-    requires std::is_same_v<X,std::any>
+    requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any>)
 constexpr auto is( X const& x ) -> bool
     { return x.type() == typeid(T); }
 
 template<typename T, typename X>
-    requires (!std::is_reference_v<T> && std::is_same_v<X,std::any>)
+    requires (!std::is_reference_v<T> && std::is_same_v<X,std::any> && !std::is_same_v<T,std::any>)
 constexpr auto as( X const& x ) -> T
     { return std::any_cast<T>( x ); }
 

regression-tests/pure2-inspect-fallback-with-variant-any-optional.cpp2

@@ -0,0 +1,25 @@
+
+main: () -> int = {
+    v: std::variant<int, std::string> = "xyzzy" as std::string;
+    a: std::any = "xyzzy" as std::string;
+    o: std::optional<std::string> = "xyzzy" as std::string;
+
+    std::cout << "\nAll these cases satisfy \"matches std::string\"\n";
+
+    test_generic(v);
+    test_generic(a);
+    test_generic(o);
+}
+
+test_generic: ( x: _ ) = {
+    std::cout
+        << "\n" << typeid(x).name() << "\n    ..."
+        << inspect x -> std::string {
+            is std::string = " matches std::string";
+            is std::variant<int, std::string> = " matches std::variant<int, std::string>";
+            is std::any = " matches std::any";
+            is std::optional<std::string> = " matches std::optional<std::string>";
+            is _   = " no match";
+        }
+        << "\n";
+}

regression-tests/test-results/pure2-inspect-fallback-with-variant-any-optional.cpp

@@ -0,0 +1,38 @@
+// ----- Cpp2 support -----
+#define CPP2_USE_MODULES         Yes
+#include "cpp2util.h"
+
+
+#line 2 "pure2-inspect-fallback-with-variant-any-optional.cpp2"
+[[nodiscard]] auto main() -> int;
+#line 14 "pure2-inspect-fallback-with-variant-any-optional.cpp2"
+auto test_generic(auto const& x) -> void;
+
+//=== Cpp2 definitions ==========================================================
+
+#line 1 "pure2-inspect-fallback-with-variant-any-optional.cpp2"
+
+[[nodiscard]] auto main() -> int{
+    std::variant<int,std::string> v { cpp2::as<std::string>("xyzzy") }; 
+    std::any a { cpp2::as<std::string>("xyzzy") }; 
+    std::optional<std::string> o { cpp2::as<std::string>("xyzzy") }; 
+
+    std::cout << "\nAll these cases satisfy \"matches std::string\"\n";
+
+    test_generic(v);
+    test_generic(a);
+    test_generic(o);
+}
+
+auto test_generic(auto const& x) -> void{
+    std::cout 
+        << "\n" << typeid(x).name() << "\n    ..." 
+        << [&] () -> std::string { auto&& __expr = x;
+            if (cpp2::is<std::string>(__expr)) { if constexpr( requires{" matches std::string";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(" matches std::string"),std::string> ) return " matches std::string"; else return std::string{}; else return std::string{}; }
+            else if (cpp2::is<std::variant<int,std::string>>(__expr)) { if constexpr( requires{" matches std::variant<int, std::string>";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(" matches std::variant<int, std::string>"),std::string> ) return " matches std::variant<int, std::string>"; else return std::string{}; else return std::string{}; }
+            else if (cpp2::is<std::any>(__expr)) { if constexpr( requires{" matches std::any";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(" matches std::any"),std::string> ) return " matches std::any"; else return std::string{}; else return std::string{}; }
+            else if (cpp2::is<std::optional<std::string>>(__expr)) { if constexpr( requires{" matches std::optional<std::string>";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(" matches std::optional<std::string>"),std::string> ) return " matches std::optional<std::string>"; else return std::string{}; else return std::string{}; }
+            else return " no match"; }
+        ()
+        << "\n";
+}

regression-tests/test-results/pure2-inspect-fallback-with-variant-any-optional.cpp2

@@ -0,0 +1,25 @@
+
+main: () -> int = {
+    v: std::variant<int, std::string> = "xyzzy" as std::string;
+    a: std::any = "xyzzy" as std::string;
+    o: std::optional<std::string> = "xyzzy" as std::string;
+
+    std::cout << "\nAll these cases satisfy \"matches std::string\"\n";
+
+    test_generic(v);
+    test_generic(a);
+    test_generic(o);
+}
+
+test_generic: ( x: _ ) = {
+    std::cout
+        << "\n" << typeid(x).name() << "\n    ..."
+        << inspect x -> std::string {
+            is std::string = " matches std::string";
+            is std::variant<int, std::string> = " matches std::variant<int, std::string>";
+            is std::any = " matches std::any";
+            is std::optional<std::string> = " matches std::optional<std::string>";
+            is _   = " no match";
+        }
+        << "\n";
+}

regression-tests/test-results/pure2-inspect-fallback-with-variant-any-optional.cpp2-output

@@ -0,0 +1,2 @@
+pure2-inspect-fallback-with-variant-any-optional.cpp2... ok (all Cpp2, passes safety checks)
+