Restore UFCS test, but current MSVC ICEs

Author: hsutter

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

@@ -38,7 +38,7 @@ d: _ == t<o.f()>(); // Fails on Clang 12 (lambda in unevaluated context).
 
 u: @struct type = {
   b: bool == o.f();
-  c: bool == :(forward x: decltype(f(o))) = x;(true); // Fails on Clang 12 (lambda in unevaluated context).
+  c: bool == :(forward x: decltype(o.f())) = x;(true); // Fails on Clang 12 (lambda in unevaluated context).
   g: (s, sz) pre(s.sz() != 0) = { }
 }
 

regression-tests/test-results/clang-12-c++20/mixed-bugfix-for-ufcs-non-local.cpp.output

@@ -106,4 +106,29 @@ mixed-bugfix-for-ufcs-non-local.cpp2:27:29: error: a lambda expression cannot ap
 ../../../include/cpp2util.h:2099:66: note: expanded from macro 'CPP2_UFCS_'
 #define CPP2_UFCS_(LAMBDADEFCAPT,SFINAE,MVFWD,QUALID,TEMPKW,...) \
                                                                  ^
-12 errors generated.
+mixed-bugfix-for-ufcs-non-local.cpp2:42:77: error: no matching function for call to object of type 'ns::u::(lambda at mixed-bugfix-for-ufcs-non-local.cpp2:42:77)'
+  requires (std::is_convertible_v<CPP2_TYPEOF(x), std::add_const_t<decltype(CPP2_UFCS_NONLOCAL(f)(o))>&>)  { return CPP2_FORWARD(x); }(true) };
+                                                                            ^~~~~~~~~~~~~~~~~~~~~
+../../../include/cpp2util.h:2137:59: note: expanded from macro 'CPP2_UFCS_NONLOCAL'
+#define CPP2_UFCS_NONLOCAL(...)                           CPP2_UFCS_(,CPP2_UFCS_IDENTITY,CPP2_UFCS_IDENTITY,(),,__VA_ARGS__)
+                                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+../../../include/cpp2util.h:2099:66: note: expanded from macro 'CPP2_UFCS_'
+#define CPP2_UFCS_(LAMBDADEFCAPT,SFINAE,MVFWD,QUALID,TEMPKW,...) \
+                                                                 ^
+mixed-bugfix-for-ufcs-non-local.cpp2:42:77: note: candidate template ignored: couldn't infer template argument 'Obj'
+../../../include/cpp2util.h:2137:59: note: expanded from macro 'CPP2_UFCS_NONLOCAL'
+#define CPP2_UFCS_NONLOCAL(...)                           CPP2_UFCS_(,CPP2_UFCS_IDENTITY,CPP2_UFCS_IDENTITY,(),,__VA_ARGS__)
+                                                          ^
+../../../include/cpp2util.h:2099:66: note: expanded from macro 'CPP2_UFCS_'
+#define CPP2_UFCS_(LAMBDADEFCAPT,SFINAE,MVFWD,QUALID,TEMPKW,...) \
+                                                                 ^
+mixed-bugfix-for-ufcs-non-local.cpp2:42:77: error: lambda expression in an unevaluated operand
+  requires (std::is_convertible_v<CPP2_TYPEOF(x), std::add_const_t<decltype(CPP2_UFCS_NONLOCAL(f)(o))>&>)  { return CPP2_FORWARD(x); }(true) };
+                                                                            ^
+../../../include/cpp2util.h:2137:59: note: expanded from macro 'CPP2_UFCS_NONLOCAL'
+#define CPP2_UFCS_NONLOCAL(...)                           CPP2_UFCS_(,CPP2_UFCS_IDENTITY,CPP2_UFCS_IDENTITY,(),,__VA_ARGS__)
+                                                          ^
+../../../include/cpp2util.h:2099:66: note: expanded from macro 'CPP2_UFCS_'
+#define CPP2_UFCS_(LAMBDADEFCAPT,SFINAE,MVFWD,QUALID,TEMPKW,...) \
+                                                                 ^
+14 errors generated.

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

@@ -97,7 +97,7 @@ auto g() -> void{
   inline CPP2_CONSTEXPR bool u::b{ CPP2_UFCS_NONLOCAL(f)(o) };
   inline CPP2_CONSTEXPR bool u::c{ [](auto&& x) -> decltype(auto)// Fails on Clang 12 (lambda in unevaluated context).
 #line 42 "mixed-bugfix-for-ufcs-non-local.cpp2"
-  requires (std::is_convertible_v<CPP2_TYPEOF(x), std::add_const_t<decltype(f(o))>&>)  { return CPP2_FORWARD(x); }(true) };
+  requires (std::is_convertible_v<CPP2_TYPEOF(x), std::add_const_t<decltype(CPP2_UFCS_NONLOCAL(f)(o))>&>)  { return CPP2_FORWARD(x); }(true) };
 #line 42 "mixed-bugfix-for-ufcs-non-local.cpp2"
   auto u::g(auto const& s, auto const& sz) -> void{
                                   if (cpp2::cpp2_default.is_active() && !(CPP2_UFCS(sz)(s) != 0) ) { cpp2::cpp2_default.report_violation(""); }}

regression-tests/test-results/msvc-2022-c++latest/mixed-bugfix-for-ufcs-non-local.cpp.output

@@ -1 +1,10 @@
 mixed-bugfix-for-ufcs-non-local.cpp
+mixed-bugfix-for-ufcs-non-local.cpp2(42): fatal error C1001: Internal compiler error.
+(compiler file 'msc1.cpp', line 1593)
+ To work around this problem, try simplifying or changing the program near the locations listed above.
+If possible please provide a repro here: https://developercommunity.visualstudio.com 
+Please choose the Technical Support command on the Visual C++ 
+ Help menu, or open the Technical Support help file for more information
+INTERNAL COMPILER ERROR in 'C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.40.33807\bin\HostX64\x64\cl.exe'
+    Please choose the Technical Support command on the Visual C++
+    Help menu, or open the Technical Support help file for more information