1328 Fixed issue comparing different numerical types as equal. (#1365)

* 1328 Fixed issue comparing different numerical types as equal.

* 1328 Added back type comparison in case of inheritance.

* Add regression test cases

---------

Signed-off-by: Herb Sutter <herb.sutter@gmail.com>
Co-authored-by: Herb Sutter <herb.sutter@gmail.com>

Author: mihaiboros

include/cpp2util.h

@@ -2102,10 +2102,8 @@ constexpr auto is( X const& x ) -> bool {
     if (!x.has_value()) {
         return std::same_as<T, empty>;
     }
-    if constexpr (requires { static_cast<const T&>(*x);}) {
-        return true;
-    }
-    return false;
+    return std::same_as<T, typename X::value_type> 
+        || std::derived_from<std::remove_pointer_t<typename X::value_type>, std::remove_pointer_t<T>>;
 }
 
 //  is Value

regression-tests/pure2-type-safety-1.cpp2

@@ -19,6 +19,14 @@ main: () -> int =
     test_generic(v,    "variant<int, int, double>");
     test_generic(a,    "any");
     test_generic(o,    "optional<int>");
+
+    oi: std::optional<int> = 5;
+    std::cout << "optional<int> is: ";
+    test_1365(oi);
+    od: std::optional<*D> = nullptr;
+    std::cout << "\noptional<*D> is: ";
+    test_1365(od);
+    std::cout << "\n";
 }
 
 test_generic: ( x, msg ) = {
@@ -28,6 +36,30 @@ test_generic: ( x, msg ) = {
     ::print( msgx + " is int? ", x is int );
 }
 
+B: type = { }
+D: type = { this: B; }
+
+test_1365: (o) = {
+    if o is int {
+        std::cout << "int ";
+    }
+    if o is bool {
+        std::cout << "bool ";
+    }
+    if o is float {
+        std::cout << "float ";
+    }
+    if o is *B {
+        std::cout << "*B ";
+    }
+    if o is *D {
+        std::cout << "*D ";
+    }
+    if o is std::string {
+        std::cout << "std::string ";
+    }
+}
+
 print: ( msg: std::string, b: bool ) = {
     bmsg: * const char;
     if b { bmsg = "true";  }

regression-tests/test-results/clang-12-c++20/pure2-type-safety-1.cpp.execution

@@ -7,3 +7,5 @@
       variant<int, int, double> is int? true
                             any is int? true
                   optional<int> is int? true
+optional<int> is: int 
+optional<*D> is: *B *D 

regression-tests/test-results/gcc-10-c++20/pure2-type-safety-1.cpp.execution

@@ -7,3 +7,5 @@
       variant<int, int, double> is int? true
                             any is int? true
                   optional<int> is int? true
+optional<int> is: int 
+optional<*D> is: *B *D 

regression-tests/test-results/gcc-14-c++2b/pure2-type-safety-1.cpp.execution

@@ -7,3 +7,5 @@
       variant<int, int, double> is int? true
                             any is int? true
                   optional<int> is int? true
+optional<int> is: int 
+optional<*D> is: *B *D 

regression-tests/test-results/msvc-2022-c++latest/pure2-type-safety-1.cpp.execution

@@ -7,3 +7,5 @@
       variant<int, int, double> is int? true
                             any is int? true
                   optional<int> is int? true
+optional<int> is: int 
+optional<*D> is: *B *D 

regression-tests/test-results/pure2-type-safety-1.cpp

@@ -8,6 +8,10 @@
 
 #line 1 "pure2-type-safety-1.cpp2"
 
+#line 39 "pure2-type-safety-1.cpp2"
+class B;
+class D;
+
 
 //=== Cpp2 type definitions and function declarations ===========================
 
@@ -16,12 +20,28 @@
 #line 2 "pure2-type-safety-1.cpp2"
 [[nodiscard]] auto main() -> int;
 
-#line 24 "pure2-type-safety-1.cpp2"
+#line 32 "pure2-type-safety-1.cpp2"
 auto test_generic(auto const& x, auto const& msg) -> void;
 
-#line 31 "pure2-type-safety-1.cpp2"
+#line 39 "pure2-type-safety-1.cpp2"
+class B {
+      public: B() = default;
+      public: B(B const&) = delete; /* No 'that' constructor, suppress copy */
+      public: auto operator=(B const&) -> void = delete;
+};
+#line 40 "pure2-type-safety-1.cpp2"
+class D: public B {
+      public: D() = default;
+      public: D(D const&) = delete; /* No 'that' constructor, suppress copy */
+      public: auto operator=(D const&) -> void = delete;
+};
+#line 41 "pure2-type-safety-1.cpp2"
+
+auto test_1365(auto const& o) -> void;
+
+#line 63 "pure2-type-safety-1.cpp2"
 auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void;
-#line 37 "pure2-type-safety-1.cpp2"
+#line 69 "pure2-type-safety-1.cpp2"
 
 #line 1 "pure2-type-safety-1.cpp2"
 
@@ -50,17 +70,47 @@ auto print(cpp2::impl::in<std::string> msg, cpp2::impl::in<bool> b) -> void;
     test_generic(cpp2::move(v), "variant<int, int, double>");
     test_generic(cpp2::move(a), "any");
     test_generic(cpp2::move(o), "optional<int>");
+
+    std::optional<int> oi {5}; 
+    std::cout << "optional<int> is: ";
+    test_1365(cpp2::move(oi));
+    std::optional<D*> od {nullptr}; 
+    std::cout << "\noptional<*D> is: ";
+    test_1365(cpp2::move(od));
+    std::cout << "\n";
 }
 
-#line 24 "pure2-type-safety-1.cpp2"
+#line 32 "pure2-type-safety-1.cpp2"
 auto test_generic(auto const& x, auto const& msg) -> void{
     std::string msgx {msg}; 
     // Full qualification is necessary to avoid ambiguity in C++23
     // C++23 defines std::print, which would be picked up here by ADL
     ::print(cpp2::move(msgx) + " is int? ", cpp2::impl::is<int>(x));
 }
 
-#line 31 "pure2-type-safety-1.cpp2"
+#line 42 "pure2-type-safety-1.cpp2"
+auto test_1365(auto const& o) -> void{
+    if (cpp2::impl::is<int>(o)) {
+        std::cout << "int ";
+    }
+    if (cpp2::impl::is<bool>(o)) {
+        std::cout << "bool ";
+    }
+    if (cpp2::impl::is<float>(o)) {
+        std::cout << "float ";
+    }
+    if (cpp2::impl::is<B*>(o)) {
+        std::cout << "*B ";
+    }
+    if (cpp2::impl::is<D*>(o)) {
+        std::cout << "*D ";
+    }
+    if (cpp2::impl::is<std::string>(o)) {
+        std::cout << "std::string ";
+    }
+}
+
+#line 63 "pure2-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; 
     if (b) { bmsg.construct("true");}

regression-tests/test-results/version

@@ -1,4 +1,4 @@
 
-cppfront compiler v0.8.1 Build A206:0852
+cppfront compiler v0.8.1 Build 10202:1808
 SPDX-License-Identifier  Apache-2.0 WITH LLVM-exception
 Copyright (c) 2022-2024  Herb Sutter