test: add unit tests for fixed UFCS corner cases

Author: JohelEGP

regression-tests/mixed-bugfix-for-ufcs-non-local.cpp2

@@ -0,0 +1,43 @@
+namespace ns {
+
+template<bool> struct t { };
+constexpr bool f(const t<true>&) { return true; }
+constexpr t<true> o{};
+
+} // namespace ns
+
+ns: namespace = {
+
+// Variables.
+
+v0: <_: t<o.f()>> bool == false; // Fails on GCC ([GCC109781][]).
+
+v1: t<o.f()> == t<true>(); // Fails on Clang 12 (lambda in unevaluated context).
+
+v2: bool == o.f();
+
+// Functions.
+
+g: <_: t<o.f()>> () = { } // Fails on GCC ([GCC109781][]).
+
+g: (_: t<o.f()>) = { } // Fails on Clang 12 (lambda in unevaluated context).
+
+g: () pre(o.f()) = { }
+
+h: () -> t<o.f()> = o; // Fails on Clang 12 (lambda in unevaluated context).
+
+// Aliases.
+
+a: <_: t<o.f()>> type == bool; // Fails on GCC ([GCC109781][]).
+
+b: <_: t<o.f()>> _ == false; // Fails on GCC ([GCC109781][]).
+
+c: type == t<o.f()>; // Fails on Clang 12 (lambda in unevaluated context).
+
+d: _ == t<o.f()>(); // Fails on Clang 12 (lambda in unevaluated context).
+
+} // namespace ns
+
+main: () = { }
+
+// [GCC109781]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109781

regression-tests/pure2-bugfix-for-ufcs-arguments.cpp2

@@ -0,0 +1,51 @@
+print_res: (x: i32) -> i32 = {
+  std::cout << x;
+  if x == 9 { std::cout << '\n'; }
+  return x;
+}
+
+t: @struct type = {
+  f: (inout this) -> i32 = print_res(0);
+  f: (inout this, _) -> i32 = print_res(1);
+  f: <_> (inout this) -> i32 = print_res(2);
+  f: <_> (inout this, _) -> i32 = print_res(3);
+  f: <_, U> (inout this, _, _) -> i32 = print_res(4);
+}
+
+f: (_: t) -> i32 = print_res(5);
+f: (_: t, _) -> i32 = print_res(6);
+f: <_> (_: t) -> i32 = print_res(7);
+f: <_> (_: t, _) -> i32 = print_res(8);
+f: <_, U> (_: t, _, _) -> i32 = print_res(9);
+
+m: t       = ();
+n: const t = ();
+a: <_, U> _ == n;
+
+_: i32 = m.f();
+_: i32 = m.f(0);
+_: i32 = m.f<t>();
+_: i32 = m.f<t>(0);
+_: i32 = m.f<t, t>(0, 0);
+_: i32 = n.f();
+_: i32 = n.f(0);
+_: i32 = n.f<t>();
+_: i32 = n.f<t>(0);
+_: i32 = n.f<t, t>(0, 0);
+_: i32 = a<t, t>.f<t, t>(0, 0);
+
+main: () = {
+  _ = m.f();
+  _ = m.f(0);
+  _ = m.f<t>();
+  _ = m.f<t>(0);
+  _ = m.f<t, t>(0, 0);
+  _ = n.f();
+  _ = n.f(0);
+  _ = n.f<t>();
+  _ = n.f<t>(0);
+  _ = n.f<t, t>(0, 0);
+  _ = a<t, t>.f<t, t>(0, 0);
+
+  _ = :(a, f) = { _ = a.f(a).f(); };
+}

regression-tests/pure2-bugfix-for-ufcs-name-lookup.cpp2

@@ -0,0 +1,107 @@
+identity: @struct type = {
+  operator(): (this, forward x) -> forward _ == x;
+}
+
+t: @struct type = {
+  f: (this) -> int == 0;
+}
+
+u: @struct type = { }
+
+ns: namespace = {
+f: (_) -> int == 1;
+} // namespace ns
+
+// v: @struct type = {
+//   f :== :(_) 0; // Pending on #706.
+//   g: (i) i.f();
+// }
+
+main: () = {
+  {
+    f := t().f();
+    assert(f == 0);
+  }
+  {
+    f: _ = t().f();
+    assert(f == 0);
+  }
+  (f := t().f()) assert(f == 0);
+  (f: _ = t().f()) assert(f == 0);
+  {
+    f :== t().f();
+    static_assert(f == 0);
+  }
+  {
+    f: _ == t().f();
+    static_assert(f == 0);
+  }
+  {
+    f := :(f) -> _ = {
+      assert(t().f() == 0);
+      return u().f();
+    }(identity());
+    _ = f;
+  }
+  { // Rejected by MSVC.
+    // f := :<f: _> (copy _: std::integral_constant<identity, f>) -> _ = {
+    //   assert(t().f() == 0);
+    //   return u().f();
+    // }(:std::integral_constant<identity, (:identity = ())> = ());
+    // _ = f;
+  }
+  {
+    f := :() = {
+      (f: identity = identity()) assert(t().f() == 0);
+      (f: identity = identity()) _ = u().f();
+    };
+    _ = f;
+  }
+  {
+    f := :() = {
+      using ns::f;
+      static_assert(t().f() == 0);
+      static_assert(u().f() == 1);
+    };
+    _ = f;
+  }
+  {
+    f := :() = {
+      static_assert(t().f() == 0);
+      g := :<T> (_: T) -> std::void_t<decltype(T().f())> = {};
+      static_assert(!std::is_invocable_v<decltype(g), u>);
+      using ns::f;
+    };
+    _ = f;
+  }
+  {
+    f := :() = {
+      using ns::f;
+      _ = :() = {
+        static_assert(t().f() == 0);
+        static_assert(u().f() == 1);
+      };
+      {
+        static_assert(t().f() == 0);
+        static_assert(u().f() == 1);
+      }
+    };
+    _ = f;
+  }
+  {
+    f := :() = {
+      _ = :() = {
+        static_assert(t().f() == 0);
+        g := :<T> (_: T) -> std::void_t<decltype(T().f())> = {};
+        static_assert(!std::is_invocable_v<decltype(g), u>);
+      };
+      {
+        static_assert(t().f() == 0);
+        g := :<T> (_: T) -> std::void_t<decltype(T().f())> = {};
+        static_assert(!std::is_invocable_v<decltype(g), u>);
+      }
+      using ns::f;
+    };
+    _ = f;
+  }
+}

regression-tests/pure2-bugfix-for-ufcs-noexcept.cpp2

@@ -0,0 +1,6 @@
+t: type = {
+  swap: (virtual inout this, that) = { } // Non-`virtual` blocked on #508, idiomatic form on #507.
+}
+main: () = {
+  static_assert(noexcept(t().swap(t()))); // Fails on Clang 12 (lambda in unevaluated context).
+}

regression-tests/pure2-bugfix-for-ufcs-sfinae.cpp2

@@ -0,0 +1,8 @@
+f: <T> () -> std::type_identity_t<decltype(T().a())> = { } // Fails on Clang 12 (lambda in unevaluated context).
+
+B: type = { }
+
+main: () = {
+  g := :<T> (_: T) -> std::void_t<decltype(f<T>())> = {};
+  static_assert(!std::is_invocable_v<decltype(g), B>);
+}

regression-tests/test-results/clang-18/mixed-bugfix-for-ufcs-non-local.cpp.execution

@@ -0,0 +1,4 @@
+0123456789
+9
+0123456789
+9

regression-tests/test-results/clang-18/mixed-bugfix-for-ufcs-non-local.cpp.output

@@ -0,0 +1,86 @@
+
+
+//=== Cpp2 type declarations ====================================================
+
+
+#include "cpp2util.h"
+
+
+#line 9 "mixed-bugfix-for-ufcs-non-local.cpp2"
+namespace ns {
+
+#line 39 "mixed-bugfix-for-ufcs-non-local.cpp2"
+}
+
+
+//=== Cpp2 type definitions and function declarations ===========================
+
+namespace ns {
+
+template<bool> struct t { };
+constexpr bool f(const t<true>&) { return true; }
+constexpr t<true> o{};
+
+} // namespace ns
+
+#line 9 "mixed-bugfix-for-ufcs-non-local.cpp2"
+namespace ns {
+
+// Variables.
+
+template<t<CPP2_UFCS_NONLOCAL(f)(o)> _> bool inline constexpr v0 = false;// Fails on GCC ([GCC109781][]).
+
+t<CPP2_UFCS_NONLOCAL(f)(o)> inline constexpr v1 = t<true>();// Fails on Clang 12 (lambda in unevaluated context).
+
+bool inline constexpr v2 = CPP2_UFCS_NONLOCAL(f)(o);
+
+// Functions.
+
+template<t<CPP2_UFCS_NONLOCAL(f)(o)> _> auto g() -> void;
+
+auto g([[maybe_unused]] cpp2::in<t<CPP2_UFCS_NONLOCAL(f)(o)>> param1) -> void;
+
+auto g() -> void;
+
+[[nodiscard]] auto h() -> t<CPP2_UFCS_NONLOCAL(f)(o)>;
+
+// Aliases.
+
+template<t<CPP2_UFCS_NONLOCAL(f)(o)> _> using a = bool;// Fails on GCC ([GCC109781][]).
+
+template<t<CPP2_UFCS_NONLOCAL(f)(o)> _> auto inline constexpr b = false;// Fails on GCC ([GCC109781][]).
+
+using c = t<CPP2_UFCS_NONLOCAL(f)(o)>;// Fails on Clang 12 (lambda in unevaluated context).
+
+auto inline constexpr d = t<CPP2_UFCS_NONLOCAL(f)(o)>();// Fails on Clang 12 (lambda in unevaluated context).
+
+} // namespace ns
+
+auto main() -> int;
+
+// [GCC109781]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109781
+
+
+//=== Cpp2 function definitions =================================================
+
+
+#line 9 "mixed-bugfix-for-ufcs-non-local.cpp2"
+namespace ns {
+
+#line 21 "mixed-bugfix-for-ufcs-non-local.cpp2"
+template<t<CPP2_UFCS_NONLOCAL(f)(o)> _> auto g() -> void{}// Fails on GCC ([GCC109781][]).
+
+auto g([[maybe_unused]] cpp2::in<t<CPP2_UFCS_NONLOCAL(f)(o)>> param1) -> void{}// Fails on Clang 12 (lambda in unevaluated context).
+
+auto g() -> void{
+                     cpp2::Default.expects(CPP2_UFCS(f)(o), "");
+#line 25 "mixed-bugfix-for-ufcs-non-local.cpp2"
+}
+
+[[nodiscard]] auto h() -> t<CPP2_UFCS_NONLOCAL(f)(o)> { return o;  }// Fails on Clang 12 (lambda in unevaluated context).
+
+#line 39 "mixed-bugfix-for-ufcs-non-local.cpp2"
+}
+
+auto main() -> int{}
+

regression-tests/test-results/clang-18/pure2-bugfix-for-ufcs-arguments.cpp.execution

@@ -0,0 +1,2 @@
+mixed-bugfix-for-ufcs-non-local.cpp2... ok (mixed Cpp1/Cpp2, Cpp2 code passes safety checks)
+