[PATCH] D152259: [Clang] Make increment bool SFINAE-friendly

[Yurong via Phabricator via cfe-commits]

yronglin updated this revision to Diff 528847.
yronglin added a comment.

Address comments


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152259/new/

https://reviews.llvm.org/D152259

Files:
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/test/SemaCXX/bool-SFINAE-friendly.cpp


Index: clang/test/SemaCXX/bool-SFINAE-friendly.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/bool-SFINAE-friendly.cpp
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 %std_cxx98-14 -fsyntax-only -verify=precxx17 %s
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify=expected %s
+// RUN: %clang_cc1 -std=c++17 -DFAILED_CXX17 -fsyntax-only -verify=failcxx17 %s
+// RUN: %clang_cc1 %std_cxx20- -fsyntax-only -verify=cxx20 %s
+// expected-no-diagnostics
+
+template<class T> auto f(T t) -> decltype(++t); // precxx17-warning {{incrementing expression of type bool is deprecated}}
+
+auto f(...) -> void;
+void g() { f(true); }
+
+#ifdef FAILED_CXX17
+
+template<class T> auto f1(T t) -> decltype(++t); // failcxx17-note {{candidate template ignored: substitution failure [with T = bool]: ISO C++17 does not allow incrementing expression of type bool}}
+auto f1(void) -> void; // failcxx17-note {{candidate function not viable: requires 0 arguments, but 1 was provided}}
+void g1() { f1(true); } // failcxx17-error {{no matching function for call to 'f1'}}
+
+#endif
+
+#if __cplusplus >= 202002L
+template <class T>
+concept can_increment = requires(T t) {
+  ++t;
+};
+
+template <class T>
+void f() {
+  static_assert(requires(T t) { ++t; }); // cxx20-error {{static assertion failed due to requirement 'requires (bool t) { <<error-expression>>; }'}}
+}
+
+int main() {
+  f<bool>(); // cxx20-note {{in instantiation of function template specialization 'f<bool>' requested here}}
+  static_assert(!can_increment<bool>); 
+
+  return 0;
+}
+#endif
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7661,7 +7661,7 @@
   "incompatible with C++17">, InGroup<DeprecatedIncrementBool>;
 def ext_increment_bool : ExtWarn<
   "ISO C++17 does not allow incrementing expression of type bool">,
-  DefaultError, InGroup<IncrementBool>;
+  DefaultError, SFINAEFailure, InGroup<IncrementBool>;
 def err_increment_decrement_enum : Error<
   "cannot %select{decrement|increment}0 expression of enum type %1">;
 


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