[PATCH] D34370: Fix for Bug 33471: Preventing operator auto from resolving to a template operator.

[Erich Keane via Phabricator via cfe-commits]

erichkeane updated this revision to Diff 103224.
erichkeane marked an inline comment as done.
erichkeane added a comment.

Hi @rsmith 
Thanks for the quick response!  I spent a while going over it, and think I have what you were looking for.  I Also added the operator auto * tests.


https://reviews.llvm.org/D34370

Files:
  lib/Sema/SemaLookup.cpp
  test/SemaCXX/cxx1y-deduced-return-type.cpp


Index: test/SemaCXX/cxx1y-deduced-return-type.cpp
===================================================================
--- test/SemaCXX/cxx1y-deduced-return-type.cpp
+++ test/SemaCXX/cxx1y-deduced-return-type.cpp
@@ -55,6 +55,25 @@
   return "goodbye";
 }
 
+// Allow 'operator auto' to call only the explicit operator auto.
+struct BothOps {
+  template <typename T> operator T();
+  template <typename T> operator T *();
+  operator auto() { return 0; }
+  operator auto *() { return this; }
+};
+struct JustTemplateOp {
+  template <typename T> operator T();
+  template <typename T> operator T *();
+};
+
+auto c() {
+  BothOps().operator auto(); // ok
+  BothOps().operator auto *(); // ok
+  JustTemplateOp().operator auto(); // expected-error {{no member named 'operator auto' in 'JustTemplateOp'}}
+  JustTemplateOp().operator auto *(); // expected-error {{no member named 'operator auto *' in 'JustTemplateOp'}}
+}
+
 auto *ptr_1() {
   return 100; // expected-error {{cannot deduce return type 'auto *' from returned value of type 'int'}}
 }
Index: lib/Sema/SemaLookup.cpp
===================================================================
--- lib/Sema/SemaLookup.cpp
+++ lib/Sema/SemaLookup.cpp
@@ -862,6 +862,19 @@
   if (!Record->isCompleteDefinition())
     return Found;
 
+  // For conversion operators, 'operator auto' should only match
+  // 'operator auto'.  Since 'auto' is not a type, it shouldn't be considered
+  // as a candidate for template substitution.
+  if (R.getLookupName().getNameKind() ==
+          DeclarationName::CXXConversionFunctionName &&
+      R.getLookupName().getCXXNameType()->getContainedDeducedType() &&
+      R.getLookupName()
+          .getCXXNameType()
+          ->getContainedDeducedType()
+          ->isUndeducedType()) {
+    return Found;
+  }
+
   for (CXXRecordDecl::conversion_iterator U = Record->conversion_begin(),
          UEnd = Record->conversion_end(); U != UEnd; ++U) {
     FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(*U);


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