Refactor places which perform contextual implicit conversions to go through a

common function. The C++1y contextual implicit conversion rules themselves are
not yet implemented, however.

This also fixes a subtle bug where template instantiation context notes were
dropped for diagnostics coming from conversions for integral constant
expressions -- we were implicitly slicing a SemaDiagnosticBuilder into a
DiagnosticBuilder when producing these diagnostics, and losing their context
notes in the process.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182406 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticSemaKinds.td

@@ -4759,13 +4759,17 @@ def err_default_init_const : Error<
 def err_delete_operand : Error<"cannot delete expression of type %0">;
 def ext_delete_void_ptr_operand : ExtWarn<
   "cannot delete expression with pointer-to-'void' type %0">;
-def err_ambiguous_delete_operand : Error<"ambiguous conversion of delete "
-                                         "expression of type %0 to a pointer">;
+def err_ambiguous_delete_operand : Error<
+  "ambiguous conversion of delete expression of type %0 to a pointer">;
 def warn_delete_incomplete : Warning<
   "deleting pointer to incomplete type %0 may cause undefined behavior">,
   InGroup<DiagGroup<"delete-incomplete">>;
 def err_delete_incomplete_class_type : Error<
   "deleting incomplete class type %0; no conversions to pointer type">;
+def err_delete_explicit_conversion : Error<
+  "converting delete expression from type %0 to type %1 invokes an explicit "
+  "conversion function">;
+def note_delete_conversion : Note<"conversion to pointer type %0">;
 def warn_delete_array_type : Warning<
   "'delete' applied to a pointer-to-array type %0 treated as delete[]">;
 def err_no_suitable_delete_member_function_found : Error<

include/clang/Sema/Sema.h

@@ -906,6 +906,15 @@ public:
       // Dispatch to Sema to emit the diagnostic.
       SemaRef.EmitCurrentDiagnostic(DiagID);
     }
+
+    /// Teach operator<< to produce an object of the correct type.
+    template<typename T>
+    friend const SemaDiagnosticBuilder &operator<<(
+        const SemaDiagnosticBuilder &Diag, const T &Value) {
+      const DiagnosticBuilder &BaseDiag = Diag;
+      BaseDiag << Value;
+      return Diag;
+    }
   };
 
   /// \brief Emit a diagnostic.
@@ -1928,58 +1937,83 @@ public:
   ExprResult CheckConvertedConstantExpression(Expr *From, QualType T,
                                               llvm::APSInt &Value, CCEKind CCE);
 
-  /// \brief Abstract base class used to diagnose problems that occur while
-  /// trying to convert an expression to integral or enumeration type.
-  class ICEConvertDiagnoser {
+  /// \brief Abstract base class used to perform a contextual implicit
+  /// conversion from an expression to any type passing a filter.
+  class ContextualImplicitConverter {
   public:
     bool Suppress;
     bool SuppressConversion;
 
-    ICEConvertDiagnoser(bool Suppress = false,
-                        bool SuppressConversion = false)
-      : Suppress(Suppress), SuppressConversion(SuppressConversion) { }
+    ContextualImplicitConverter(bool Suppress = false,
+                                bool SuppressConversion = false)
+        : Suppress(Suppress), SuppressConversion(SuppressConversion) {}
+
+    /// \brief Determine whether the specified type is a valid destination type
+    /// for this conversion.
+    virtual bool match(QualType T) = 0;
 
     /// \brief Emits a diagnostic complaining that the expression does not have
     /// integral or enumeration type.
-    virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
-                                             QualType T) = 0;
+    virtual SemaDiagnosticBuilder
+    diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) = 0;
 
     /// \brief Emits a diagnostic when the expression has incomplete class type.
-    virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
-                                                 QualType T) = 0;
+    virtual SemaDiagnosticBuilder
+    diagnoseIncomplete(Sema &S, SourceLocation Loc, QualType T) = 0;
 
     /// \brief Emits a diagnostic when the only matching conversion function
     /// is explicit.
-    virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
-                                                   QualType T,
-                                                   QualType ConvTy) = 0;
+    virtual SemaDiagnosticBuilder diagnoseExplicitConv(
+        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;
 
     /// \brief Emits a note for the explicit conversion function.
-    virtual DiagnosticBuilder
+    virtual SemaDiagnosticBuilder
     noteExplicitConv(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;
 
     /// \brief Emits a diagnostic when there are multiple possible conversion
     /// functions.
-    virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
-                                                QualType T) = 0;
+    virtual SemaDiagnosticBuilder
+    diagnoseAmbiguous(Sema &S, SourceLocation Loc, QualType T) = 0;
 
     /// \brief Emits a note for one of the candidate conversions.
-    virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
-                                            QualType ConvTy) = 0;
+    virtual SemaDiagnosticBuilder
+    noteAmbiguous(Sema &S, CXXConversionDecl *Conv, QualType ConvTy) = 0;
 
     /// \brief Emits a diagnostic when we picked a conversion function
     /// (for cases when we are not allowed to pick a conversion function).
-    virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
-                                                 QualType T,
-                                                 QualType ConvTy) = 0;
+    virtual SemaDiagnosticBuilder diagnoseConversion(
+        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) = 0;
 
-    virtual ~ICEConvertDiagnoser() {}
+    virtual ~ContextualImplicitConverter() {}
   };
 
-  ExprResult
-  ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *FromE,
-                                     ICEConvertDiagnoser &Diagnoser,
-                                     bool AllowScopedEnumerations);
+  class ICEConvertDiagnoser : public ContextualImplicitConverter {
+    bool AllowScopedEnumerations;
+
+  public:
+    ICEConvertDiagnoser(bool AllowScopedEnumerations,
+                        bool Suppress, bool SuppressConversion)
+        : ContextualImplicitConverter(Suppress, SuppressConversion),
+          AllowScopedEnumerations(AllowScopedEnumerations) {}
+
+    /// Match an integral or (possibly scoped) enumeration type.
+    bool match(QualType T);
+
+    SemaDiagnosticBuilder
+    diagnoseNoMatch(Sema &S, SourceLocation Loc, QualType T) {
+      return diagnoseNotInt(S, Loc, T);
+    }
+
+    /// \brief Emits a diagnostic complaining that the expression does not have
+    /// integral or enumeration type.
+    virtual SemaDiagnosticBuilder
+    diagnoseNotInt(Sema &S, SourceLocation Loc, QualType T) = 0;
+  };
+
+  /// Perform a contextual implicit conversion.
+  ExprResult PerformContextualImplicitConversion(
+      SourceLocation Loc, Expr *FromE, ContextualImplicitConverter &Converter);
+
 
   enum ObjCSubscriptKind {
     OS_Array,

lib/Sema/SemaExpr.cpp

@@ -10391,112 +10391,52 @@ Sema::VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result,
     //   have a single non-explicit conversion function to an integral or
     //   unscoped enumeration type
     ExprResult Converted;
-    if (!Diagnoser.Suppress) {
-      class CXX11ConvertDiagnoser : public ICEConvertDiagnoser {
-      public:
-        CXX11ConvertDiagnoser() : ICEConvertDiagnoser(false, true) { }
-        
-        virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
-                                                 QualType T) {
-          return S.Diag(Loc, diag::err_ice_not_integral) << T;
-        }
-        
-        virtual DiagnosticBuilder diagnoseIncomplete(Sema &S,
-                                                     SourceLocation Loc,
-                                                     QualType T) {
-          return S.Diag(Loc, diag::err_ice_incomplete_type) << T;
-        }
-        
-        virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S,
-                                                       SourceLocation Loc,
-                                                       QualType T,
-                                                       QualType ConvTy) {
-          return S.Diag(Loc, diag::err_ice_explicit_conversion) << T << ConvTy;
-        }
-        
-        virtual DiagnosticBuilder noteExplicitConv(Sema &S,
-                                                   CXXConversionDecl *Conv,
-                                                   QualType ConvTy) {
-          return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
-                   << ConvTy->isEnumeralType() << ConvTy;
-        }
-        
-        virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
-                                                    QualType T) {
-          return S.Diag(Loc, diag::err_ice_ambiguous_conversion) << T;
-        }
-        
-        virtual DiagnosticBuilder noteAmbiguous(Sema &S,
-                                                CXXConversionDecl *Conv,
-                                                QualType ConvTy) {
-          return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
-                   << ConvTy->isEnumeralType() << ConvTy;
-        }
-        
-        virtual DiagnosticBuilder diagnoseConversion(Sema &S,
-                                                     SourceLocation Loc,
-                                                     QualType T,
-                                                     QualType ConvTy) {
-          return DiagnosticBuilder::getEmpty();
-        }
-      } ConvertDiagnoser;
+    class CXX11ConvertDiagnoser : public ICEConvertDiagnoser {
+    public:
+      CXX11ConvertDiagnoser(bool Silent)
+          : ICEConvertDiagnoser(/*AllowScopedEnumerations*/false,
+                                Silent, true) {}
 
-      Converted = ConvertToIntegralOrEnumerationType(DiagLoc, E,
-                                                     ConvertDiagnoser,
-                                             /*AllowScopedEnumerations*/ false);
-    } else {
-      // The caller wants to silently enquire whether this is an ICE. Don't
-      // produce any diagnostics if it isn't.
-      class SilentICEConvertDiagnoser : public ICEConvertDiagnoser {
-      public:
-        SilentICEConvertDiagnoser() : ICEConvertDiagnoser(true, true) { }
-        
-        virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
-                                                 QualType T) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder diagnoseIncomplete(Sema &S,
-                                                     SourceLocation Loc,
-                                                     QualType T) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S,
-                                                       SourceLocation Loc,
-                                                       QualType T,
-                                                       QualType ConvTy) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder noteExplicitConv(Sema &S,
-                                                   CXXConversionDecl *Conv,
-                                                   QualType ConvTy) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
-                                                    QualType T) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder noteAmbiguous(Sema &S,
-                                                CXXConversionDecl *Conv,
-                                                QualType ConvTy) {
-          return DiagnosticBuilder::getEmpty();
-        }
-        
-        virtual DiagnosticBuilder diagnoseConversion(Sema &S,
-                                                     SourceLocation Loc,
-                                                     QualType T,
-                                                     QualType ConvTy) {
-          return DiagnosticBuilder::getEmpty();
-        }
-      } ConvertDiagnoser;
-      
-      Converted = ConvertToIntegralOrEnumerationType(DiagLoc, E,
-                                                     ConvertDiagnoser, false);
-    }
+      virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
+                                                   QualType T) {
+        return S.Diag(Loc, diag::err_ice_not_integral) << T;
+      }
+
+      virtual SemaDiagnosticBuilder diagnoseIncomplete(
+          Sema &S, SourceLocation Loc, QualType T) {
+        return S.Diag(Loc, diag::err_ice_incomplete_type) << T;
+      }
+
+      virtual SemaDiagnosticBuilder diagnoseExplicitConv(
+          Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
+        return S.Diag(Loc, diag::err_ice_explicit_conversion) << T << ConvTy;
+      }
+
+      virtual SemaDiagnosticBuilder noteExplicitConv(
+          Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
+        return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
+                 << ConvTy->isEnumeralType() << ConvTy;
+      }
+
+      virtual SemaDiagnosticBuilder diagnoseAmbiguous(
+          Sema &S, SourceLocation Loc, QualType T) {
+        return S.Diag(Loc, diag::err_ice_ambiguous_conversion) << T;
+      }
+
+      virtual SemaDiagnosticBuilder noteAmbiguous(
+          Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
+        return S.Diag(Conv->getLocation(), diag::note_ice_conversion_here)
+                 << ConvTy->isEnumeralType() << ConvTy;
+      }
+
+      virtual SemaDiagnosticBuilder diagnoseConversion(
+          Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
+        llvm_unreachable("conversion functions are permitted");
+      }
+    } ConvertDiagnoser(Diagnoser.Suppress);
+
+    Converted = PerformContextualImplicitConversion(DiagLoc, E,
+                                                    ConvertDiagnoser);
     if (Converted.isInvalid())
       return Converted;
     E = Converted.take();

lib/Sema/SemaExprCXX.cpp

@@ -1180,54 +1180,53 @@ Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   // C++11 [expr.new]p6: The expression [...] shall be of integral or unscoped
   //   enumeration type, or a class type for which a single non-explicit
   //   conversion function to integral or unscoped enumeration type exists.
+  // C++1y [expr.new]p6: The expression [...] is implicitly converted to
+  //   std::size_t. (FIXME)
   if (ArraySize && !ArraySize->isTypeDependent()) {
     class SizeConvertDiagnoser : public ICEConvertDiagnoser {
       Expr *ArraySize;
-      
+
     public:
       SizeConvertDiagnoser(Expr *ArraySize)
-        : ICEConvertDiagnoser(false, false), ArraySize(ArraySize) { }
-      
-      virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
-                                               QualType T) {
+          : ICEConvertDiagnoser(/*AllowScopedEnumerations*/false, false, false),
+            ArraySize(ArraySize) {}
+
+      virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
+                                                   QualType T) {
         return S.Diag(Loc, diag::err_array_size_not_integral)
                  << S.getLangOpts().CPlusPlus11 << T;
       }
-      
-      virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
-                                                   QualType T) {
+
+      virtual SemaDiagnosticBuilder diagnoseIncomplete(
+          Sema &S, SourceLocation Loc, QualType T) {
         return S.Diag(Loc, diag::err_array_size_incomplete_type)
                  << T << ArraySize->getSourceRange();
       }
-      
-      virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S,
-                                                     SourceLocation Loc,
-                                                     QualType T,
-                                                     QualType ConvTy) {
+
+      virtual SemaDiagnosticBuilder diagnoseExplicitConv(
+          Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
         return S.Diag(Loc, diag::err_array_size_explicit_conversion) << T << ConvTy;
       }
-      
-      virtual DiagnosticBuilder noteExplicitConv(Sema &S,
-                                                 CXXConversionDecl *Conv,
-                                                 QualType ConvTy) {
+
+      virtual SemaDiagnosticBuilder noteExplicitConv(
+          Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
         return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
                  << ConvTy->isEnumeralType() << ConvTy;
       }
-      
-      virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
-                                                  QualType T) {
+
+      virtual SemaDiagnosticBuilder diagnoseAmbiguous(
+          Sema &S, SourceLocation Loc, QualType T) {
         return S.Diag(Loc, diag::err_array_size_ambiguous_conversion) << T;
       }
-      
-      virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
-                                              QualType ConvTy) {
+
+      virtual SemaDiagnosticBuilder noteAmbiguous(
+          Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
         return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
                  << ConvTy->isEnumeralType() << ConvTy;
       }
-      
-      virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
-                                                   QualType T,
-                                                   QualType ConvTy) {
+
+      virtual SemaDiagnosticBuilder diagnoseConversion(
+          Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
         return S.Diag(Loc,
                       S.getLangOpts().CPlusPlus11
                         ? diag::warn_cxx98_compat_array_size_conversion
@@ -1237,8 +1236,7 @@ Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
     } SizeDiagnoser(ArraySize);
 
     ExprResult ConvertedSize
-      = ConvertToIntegralOrEnumerationType(StartLoc, ArraySize, SizeDiagnoser,
-                                           /*AllowScopedEnumerations*/ false);
+      = PerformContextualImplicitConversion(StartLoc, ArraySize, SizeDiagnoser);
     if (ConvertedSize.isInvalid())
       return ExprError();
 
@@ -2054,7 +2052,8 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
                      bool ArrayForm, Expr *ExE) {
   // C++ [expr.delete]p1:
   //   The operand shall have a pointer type, or a class type having a single
-  //   conversion function to a pointer type. The result has type void.
+  //   non-explicit conversion function to a pointer type. The result has type
+  //   void.
   //
   // DR599 amends "pointer type" to "pointer to object type" in both cases.
 
@@ -2071,59 +2070,65 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
 
     QualType Type = Ex.get()->getType();
 
-    if (const RecordType *Record = Type->getAs<RecordType>()) {
-      if (RequireCompleteType(StartLoc, Type,
-                              diag::err_delete_incomplete_class_type))
-        return ExprError();
+    class DeleteConverter : public ContextualImplicitConverter {
+    public:
+      DeleteConverter() : ContextualImplicitConverter(false, true) {}
 
-      SmallVector<CXXConversionDecl*, 4> ObjectPtrConversions;
-
-      CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
-      std::pair<CXXRecordDecl::conversion_iterator,
-                CXXRecordDecl::conversion_iterator>
-        Conversions = RD->getVisibleConversionFunctions();
-      for (CXXRecordDecl::conversion_iterator
-             I = Conversions.first, E = Conversions.second; I != E; ++I) {
-        NamedDecl *D = I.getDecl();
-        if (isa<UsingShadowDecl>(D))
-          D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-        // Skip over templated conversion functions; they aren't considered.
-        if (isa<FunctionTemplateDecl>(D))
-          continue;
-
-        CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
-
-        QualType ConvType = Conv->getConversionType().getNonReferenceType();
+      bool match(QualType ConvType) {
+        // FIXME: If we have an operator T* and an operator void*, we must pick
+        // the operator T*.
         if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
           if (ConvPtrType->getPointeeType()->isIncompleteOrObjectType())
-            ObjectPtrConversions.push_back(Conv);
+            return true;
+        return false;
       }
-      if (ObjectPtrConversions.size() == 1) {
-        // We have a single conversion to a pointer-to-object type. Perform
-        // that conversion.
-        // TODO: don't redo the conversion calculation.
-        ExprResult Res =
-          PerformImplicitConversion(Ex.get(),
-                            ObjectPtrConversions.front()->getConversionType(),
-                                    AA_Converting);
-        if (Res.isUsable()) {
-          Ex = Res;
-          Type = Ex.get()->getType();
-        }
-      }
-      else if (ObjectPtrConversions.size() > 1) {
-        Diag(StartLoc, diag::err_ambiguous_delete_operand)
-              << Type << Ex.get()->getSourceRange();
-        for (unsigned i= 0; i < ObjectPtrConversions.size(); i++)
-          NoteOverloadCandidate(ObjectPtrConversions[i]);
-        return ExprError();
-      }
-    }
 
-    if (!Type->isPointerType())
-      return ExprError(Diag(StartLoc, diag::err_delete_operand)
-        << Type << Ex.get()->getSourceRange());
+      SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
+                                            QualType T) {
+        return S.Diag(Loc, diag::err_delete_operand) << T;
+      }
+
+      SemaDiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
+                                               QualType T) {
+        return S.Diag(Loc, diag::err_delete_incomplete_class_type) << T;
+      }
+
+      SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
+                                                 QualType T, QualType ConvTy) {
+        return S.Diag(Loc, diag::err_delete_explicit_conversion) << T << ConvTy;
+      }
+
+      SemaDiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv,
+                                             QualType ConvTy) {
+        return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
+          << ConvTy;
+      }
+
+      SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
+                                              QualType T) {
+        return S.Diag(Loc, diag::err_ambiguous_delete_operand) << T;
+      }
+
+      SemaDiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
+                                          QualType ConvTy) {
+        return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
+          << ConvTy;
+      }
+
+      SemaDiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
+                                               QualType T, QualType ConvTy) {
+        llvm_unreachable("conversion functions are permitted");
+      }
+    } Converter;
+
+    Ex = PerformContextualImplicitConversion(StartLoc, Ex.take(), Converter);
+    if (Ex.isInvalid())
+      return ExprError();
+    Type = Ex.get()->getType();
+    if (!Converter.match(Type))
+      // FIXME: PerformContextualImplicitConversion should return ExprError
+      //        itself in this case.
+      return ExprError();
 
     QualType Pointee = Type->getAs<PointerType>()->getPointeeType();
     QualType PointeeElem = Context.getBaseElementType(Pointee);
@@ -2246,7 +2251,6 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
                       PDiag(diag::err_access_dtor) << PointeeElem);
       }
     }
-
   }
 
   return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm,

lib/Sema/SemaOverload.cpp

@@ -5116,34 +5116,31 @@ ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
 
 /// Determine whether the provided type is an integral type, or an enumeration
 /// type of a permitted flavor.
-static bool isIntegralOrEnumerationType(QualType T, bool AllowScopedEnum) {
-  return AllowScopedEnum ? T->isIntegralOrEnumerationType()
-                         : T->isIntegralOrUnscopedEnumerationType();
+bool Sema::ICEConvertDiagnoser::match(QualType T) {
+  return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
+                                 : T->isIntegralOrUnscopedEnumerationType();
 }
 
-/// \brief Attempt to convert the given expression to an integral or
-/// enumeration type.
+/// \brief Attempt to convert the given expression to a type which is accepted
+/// by the given converter.
 ///
-/// This routine will attempt to convert an expression of class type to an
-/// integral or enumeration type, if that class type only has a single
-/// conversion to an integral or enumeration type.
+/// This routine will attempt to convert an expression of class type to a
+/// type accepted by the specified converter. In C++11 and before, the class
+/// must have a single non-explicit conversion function converting to a matching
+/// type. In C++1y, there can be multiple such conversion functions, but only
+/// one target type.
 ///
 /// \param Loc The source location of the construct that requires the
 /// conversion.
 ///
 /// \param From The expression we're converting from.
 ///
-/// \param Diagnoser Used to output any diagnostics.
-///
-/// \param AllowScopedEnumerations Specifies whether conversions to scoped
-/// enumerations should be considered.
+/// \param Converter Used to control and diagnose the conversion process.
 ///
 /// \returns The expression, converted to an integral or enumeration type if
 /// successful.
-ExprResult
-Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
-                                         ICEConvertDiagnoser &Diagnoser,
-                                         bool AllowScopedEnumerations) {
+ExprResult Sema::PerformContextualImplicitConversion(
+    SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
   // We can't perform any more checking for type-dependent expressions.
   if (From->isTypeDependent())
     return Owned(From);
@@ -5155,34 +5152,34 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
     From = result.take();
   }
 
-  // If the expression already has integral or enumeration type, we're golden.
+  // If the expression already has a matching type, we're golden.
   QualType T = From->getType();
-  if (isIntegralOrEnumerationType(T, AllowScopedEnumerations))
+  if (Converter.match(T))
     return DefaultLvalueConversion(From);
 
   // FIXME: Check for missing '()' if T is a function type?
 
-  // If we don't have a class type in C++, there's no way we can get an
-  // expression of integral or enumeration type.
+  // We can only perform contextual implicit conversions on objects of class
+  // type.
   const RecordType *RecordTy = T->getAs<RecordType>();
   if (!RecordTy || !getLangOpts().CPlusPlus) {
-    if (!Diagnoser.Suppress)
-      Diagnoser.diagnoseNotInt(*this, Loc, T) << From->getSourceRange();
+    if (!Converter.Suppress)
+      Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
     return Owned(From);
   }
 
   // We must have a complete class type.
   struct TypeDiagnoserPartialDiag : TypeDiagnoser {
-    ICEConvertDiagnoser &Diagnoser;
+    ContextualImplicitConverter &Converter;
     Expr *From;
-    
-    TypeDiagnoserPartialDiag(ICEConvertDiagnoser &Diagnoser, Expr *From)
-      : TypeDiagnoser(Diagnoser.Suppress), Diagnoser(Diagnoser), From(From) {}
-    
+
+    TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
+        : TypeDiagnoser(Converter.Suppress), Converter(Converter), From(From) {}
+
     virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) {
-      Diagnoser.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
+      Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
     }
-  } IncompleteDiagnoser(Diagnoser, From);
+  } IncompleteDiagnoser(Converter, From);
 
   if (RequireCompleteType(Loc, T, IncompleteDiagnoser))
     return Owned(From);
@@ -5201,9 +5198,8 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
          I = Conversions.first, E = Conversions.second; I != E; ++I) {
     if (CXXConversionDecl *Conversion
           = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
-      if (isIntegralOrEnumerationType(
-            Conversion->getConversionType().getNonReferenceType(),
-            AllowScopedEnumerations)) {
+      if (Converter.match(
+              Conversion->getConversionType().getNonReferenceType())) {
         if (Conversion->isExplicit())
           ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
         else
@@ -5212,9 +5208,10 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
     }
   }
 
+  // FIXME: Implement the C++11 rules!
   switch (ViableConversions.size()) {
   case 0:
-    if (ExplicitConversions.size() == 1 && !Diagnoser.Suppress) {
+    if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
       DeclAccessPair Found = ExplicitConversions[0];
       CXXConversionDecl *Conversion
         = cast<CXXConversionDecl>(Found->getUnderlyingDecl());
@@ -5226,12 +5223,12 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
       std::string TypeStr;
       ConvTy.getAsStringInternal(TypeStr, getPrintingPolicy());
 
-      Diagnoser.diagnoseExplicitConv(*this, Loc, T, ConvTy)
+      Converter.diagnoseExplicitConv(*this, Loc, T, ConvTy)
         << FixItHint::CreateInsertion(From->getLocStart(),
                                       "static_cast<" + TypeStr + ">(")
         << FixItHint::CreateInsertion(PP.getLocForEndOfToken(From->getLocEnd()),
                                       ")");
-      Diagnoser.noteExplicitConv(*this, Conversion, ConvTy);
+      Converter.noteExplicitConv(*this, Conversion, ConvTy);
 
       // If we aren't in a SFINAE context, build a call to the
       // explicit conversion function.
@@ -5262,11 +5259,11 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
       = cast<CXXConversionDecl>(Found->getUnderlyingDecl());
     QualType ConvTy
       = Conversion->getConversionType().getNonReferenceType();
-    if (!Diagnoser.SuppressConversion) {
+    if (!Converter.SuppressConversion) {
       if (isSFINAEContext())
         return ExprError();
 
-      Diagnoser.diagnoseConversion(*this, Loc, T, ConvTy)
+      Converter.diagnoseConversion(*this, Loc, T, ConvTy)
         << From->getSourceRange();
     }
 
@@ -5283,24 +5280,22 @@ Sema::ConvertToIntegralOrEnumerationType(SourceLocation Loc, Expr *From,
   }
 
   default:
-    if (Diagnoser.Suppress)
+    if (Converter.Suppress)
       return ExprError();
 
-    Diagnoser.diagnoseAmbiguous(*this, Loc, T) << From->getSourceRange();
+    Converter.diagnoseAmbiguous(*this, Loc, T) << From->getSourceRange();
     for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
       CXXConversionDecl *Conv
         = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
       QualType ConvTy = Conv->getConversionType().getNonReferenceType();
-      Diagnoser.noteAmbiguous(*this, Conv, ConvTy);
+      Converter.noteAmbiguous(*this, Conv, ConvTy);
     }
     return Owned(From);
   }
 
-  if (!isIntegralOrEnumerationType(From->getType(), AllowScopedEnumerations) &&
-      !Diagnoser.Suppress) {
-    Diagnoser.diagnoseNotInt(*this, Loc, From->getType())
+  if (!Converter.match(From->getType()) && !Converter.Suppress)
+    Converter.diagnoseNoMatch(*this, Loc, From->getType())
       << From->getSourceRange();
-  }
 
   return DefaultLvalueConversion(From);
 }

lib/Sema/SemaStmt.cpp

@@ -592,52 +592,50 @@ Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
 
   public:
     SwitchConvertDiagnoser(Expr *Cond)
-      : ICEConvertDiagnoser(false, true), Cond(Cond) { }
+        : ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
+          Cond(Cond) {}
 
-    virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
-                                             QualType T) {
+    virtual SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
+                                                 QualType T) {
       return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
     }
 
-    virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
-                                                 QualType T) {
+    virtual SemaDiagnosticBuilder diagnoseIncomplete(
+        Sema &S, SourceLocation Loc, QualType T) {
       return S.Diag(Loc, diag::err_switch_incomplete_class_type)
                << T << Cond->getSourceRange();
     }
 
-    virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
-                                                   QualType T,
-                                                   QualType ConvTy) {
+    virtual SemaDiagnosticBuilder diagnoseExplicitConv(
+        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
       return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
     }
 
-    virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv,
-                                               QualType ConvTy) {
+    virtual SemaDiagnosticBuilder noteExplicitConv(
+        Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
       return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
         << ConvTy->isEnumeralType() << ConvTy;
     }
 
-    virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
-                                                QualType T) {
+    virtual SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
+                                                    QualType T) {
       return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
     }
 
-    virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
-                                            QualType ConvTy) {
+    virtual SemaDiagnosticBuilder noteAmbiguous(
+        Sema &S, CXXConversionDecl *Conv, QualType ConvTy) {
       return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
       << ConvTy->isEnumeralType() << ConvTy;
     }
 
-    virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
-                                                 QualType T,
-                                                 QualType ConvTy) {
-      return DiagnosticBuilder::getEmpty();
+    virtual SemaDiagnosticBuilder diagnoseConversion(
+        Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) {
+      llvm_unreachable("conversion functions are permitted");
     }
   } SwitchDiagnoser(Cond);
 
-  CondResult
-    = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser,
-                                         /*AllowScopedEnumerations*/ true);
+  CondResult =
+      PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
   if (CondResult.isInvalid()) return StmtError();
   Cond = CondResult.take();
 

test/SemaCXX/conversion-delete-expr.cpp

@@ -2,11 +2,11 @@
 
 // Test1
 struct B {
-  operator char *(); // expected-note {{candidate function}}
+  operator char *(); // expected-note {{conversion to pointer type}}
 };
 
 struct D : B {
-  operator int *(); // expected-note {{candidate function}}
+  operator int *(); // expected-note {{conversion to pointer type}}
 };
 
 void f (D d)
@@ -30,11 +30,11 @@ void f1 (D1 d)
 
 // Test3
 struct B2 {
-  operator const int *();	// expected-note {{candidate function}}
+  operator const int *(); // expected-note {{conversion to pointer type}}
 };
 
 struct D2 : B2 {
-  operator int *();	// expected-note {{candidate function}}
+  operator int *(); // expected-note {{conversion to pointer type}}
 };
 
 void f2 (D2 d)
@@ -44,11 +44,11 @@ void f2 (D2 d)
 
 // Test4
 struct B3 {
-  operator const int *();	// expected-note {{candidate function}}
+  operator const int *(); // expected-note {{conversion to pointer type}}
 };
 
 struct A3 {
-  operator const int *();	// expected-note {{candidate function}}
+  operator const int *(); // expected-note {{conversion to pointer type}}
 };
 
 struct D3 : A3, B3 {
@@ -78,7 +78,7 @@ void f5(X1 x) { delete x; }  // OK. In selecting a conversion to pointer functio
 
 // Test7
 struct Base {
-   operator int*();	
+   operator int*();
 };
 
 struct Derived : Base {
@@ -87,9 +87,9 @@ struct Derived : Base {
 };
 
 void foo6(const Derived cd, Derived d) {
-	// overload resolution selects Derived::operator int*() const;
-	delete cd;
-	delete d;	
+  // overload resolution selects Derived::operator int*() const;
+  delete cd;
+  delete d;
 }
 
 // Test8
@@ -104,6 +104,6 @@ struct DD : BB {
 
 void foo7 (DD d)
 {
-        // OK. In selecting a conversion to pointer function, template convesions are skipped.
-	delete d;
+  // OK. In selecting a conversion to pointer function, template convesions are skipped.
+  delete d;
 }

test/SemaCXX/explicit.cpp

@@ -145,14 +145,14 @@ namespace Conversion {
       operator int*();
     };
     struct NotPtr {
-      explicit operator int*();
+      explicit operator int*(); // expected-note {{conversion}}
     };
     
     Ptr    p;
     NotPtr np;
     
     delete p;
-    delete np; // expected-error {{cannot delete expression of type 'NotPtr'}}
+    delete np; // expected-error {{converting delete expression from type 'NotPtr' to type 'int *' invokes an explicit conversion function}}
   }
   
   void testFunctionPointer()

test/SemaCXX/new-delete.cpp

@@ -116,8 +116,8 @@ struct X1 {
 };
 
 struct X2 {
-  operator int*(); // expected-note {{candidate function}}
-  operator float*(); // expected-note {{candidate function}}
+  operator int*(); // expected-note {{conversion}}
+  operator float*(); // expected-note {{conversion}}
 };
 
 void test_delete_conv(X0 x0, X1 x1, X2 x2) {

test/SemaCXX/switch.cpp

@@ -85,3 +85,18 @@ void local_class(int n) {
     }();
   }
 }
+
+namespace Conversion {
+  struct S {
+    explicit operator int(); // expected-note {{conversion}}
+  };
+  template<typename T> void f(T t) {
+    switch (t) { // expected-error {{explicit conversion}}
+    case 0:
+      return;
+    default:
+      break;
+    }
+  }
+  template void f(S); // expected-note {{instantiation of}}
+}