[PATCH] D64874: [Sema] Improve handling of function pointer conversions

[Mark de Wever via Phabricator via cfe-commits]

Mordante updated this revision to Diff 218215.
Mordante added a comment.

Addresses the review remarks:

- resultTy -> ResultTy
- Move all unit tests in one file
- Change the unit test to use `-verify` instead of `FileCheck`
- Use PR40024 instead of link to Bugzilla


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64874/new/

https://reviews.llvm.org/D64874

Files:
  clang/lib/Sema/SemaTemplate.cpp
  clang/test/CXX/conv/conv.fctptr/template-noexcept.cpp


Index: clang/test/CXX/conv/conv.fctptr/template-noexcept.cpp
===================================================================
--- /dev/null
+++ clang/test/CXX/conv/conv.fctptr/template-noexcept.cpp
@@ -0,0 +1,44 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -std=c++14 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -std=c++2a -fsyntax-only -verify %s
+
+// Starting with C++17 the noexcept is part of the function signature but
+// a noexcept function can be converted to a noexcept(false) function.
+// The tests were added for PR40024.
+
+#if __cplusplus < 201703L
+// expected-no-diagnostics
+#endif
+
+namespace valid_conversion {
+struct S {
+  int f(void) noexcept { return 110; }
+} s;
+
+template <int (S::*a)(void)>
+int f10(void) { return (s.*a)(); }
+
+int foo(void) {
+  return f10<&S::f>();
+}
+} // namespace valid_conversion
+
+namespace invalid_conversion {
+struct S {
+  int f(void) { return 110; }
+} s;
+
+#if __cplusplus >= 201703L
+// expected-note at +3 {{candidate template ignored: invalid explicitly-specified argument for template parameter 'a'}}
+#endif
+template <int (S::*a)(void) noexcept>
+int f10(void) { return (s.*a)(); }
+
+#if __cplusplus >= 201703L
+// expected-error at +3 {{no matching function for call to 'f10'}}
+#endif
+int foo(void) {
+  return f10<&S::f>();
+}
+} // namespace invalid_conversion
Index: clang/lib/Sema/SemaTemplate.cpp
===================================================================
--- clang/lib/Sema/SemaTemplate.cpp
+++ clang/lib/Sema/SemaTemplate.cpp
@@ -6991,6 +6991,14 @@
                                     ObjCLifetimeConversion))
         RefExpr = ImpCastExprToType(RefExpr.get(), ParamType.getUnqualifiedType(), CK_NoOp);
 
+      // Starting with C++17 the noexcept is part of the function signature but
+      // a noexcept function can be converted to a noexcept(false) function.
+      QualType ResultTy;
+      if (getLangOpts().CPlusPlus17 &&
+          IsFunctionConversion(((Expr *)RefExpr.get())->getType(),
+                               ParamType.getUnqualifiedType(), ResultTy))
+        RefExpr = ImpCastExprToType(RefExpr.get(), ResultTy, CK_NoOp);
+
       assert(!RefExpr.isInvalid() &&
              Context.hasSameType(((Expr*) RefExpr.get())->getType(),
                                  ParamType.getUnqualifiedType()));


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