Rework how we support C++ implicit member accesses. If we can resolve an

implicit member access to a specific declaration, go ahead and create
it as a DeclRefExpr or a MemberExpr (with implicit CXXThisExpr base) as
appropriate.  Otherwise, create an UnresolvedMemberExpr or
DependentScopeMemberExpr with a null base expression.

By representing implicit accesses directly in the AST, we get the ability
to correctly delay the decision about whether it's actually an instance
member access or not until resolution is complete.  This permits us
to correctly avoid diagnosing the 'problem' of 'MyType::foo()'
where the relationship to the type isn't really known until instantiation.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90266 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 19 deletions

diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index d1a0390a0a..7a6fbdca8b 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -518,7 +518,8 @@ Stmt::child_iterator CXXUnresolvedConstructExpr::child_end() {
 }
 
 CXXDependentScopeMemberExpr::CXXDependentScopeMemberExpr(ASTContext &C,
-                                                 Expr *Base, bool IsArrow,
+                                                 Expr *Base, QualType BaseType,
+                                                 bool IsArrow,
                                                  SourceLocation OperatorLoc,
                                                  NestedNameSpecifier *Qualifier,
                                                  SourceRange QualifierRange,
@@ -527,8 +528,8 @@ CXXDependentScopeMemberExpr::CXXDependentScopeMemberExpr(ASTContext &C,
                                                  SourceLocation MemberLoc,
                                    const TemplateArgumentListInfo *TemplateArgs)
   : Expr(CXXDependentScopeMemberExprClass, C.DependentTy, true, true),
-    Base(Base), IsArrow(IsArrow),
-    HasExplicitTemplateArgumentList(TemplateArgs),
+    Base(Base), BaseType(BaseType), IsArrow(IsArrow),
+    HasExplicitTemplateArgs(TemplateArgs != 0),
     OperatorLoc(OperatorLoc),
     Qualifier(Qualifier), QualifierRange(QualifierRange),
     FirstQualifierFoundInScope(FirstQualifierFoundInScope),
@@ -539,7 +540,7 @@ CXXDependentScopeMemberExpr::CXXDependentScopeMemberExpr(ASTContext &C,
 
 CXXDependentScopeMemberExpr *
 CXXDependentScopeMemberExpr::Create(ASTContext &C,
-                                Expr *Base, bool IsArrow,
+                                Expr *Base, QualType BaseType, bool IsArrow,
                                 SourceLocation OperatorLoc,
                                 NestedNameSpecifier *Qualifier,
                                 SourceRange QualifierRange,
@@ -548,22 +549,22 @@ CXXDependentScopeMemberExpr::Create(ASTContext &C,
                                 SourceLocation MemberLoc,
                                 const TemplateArgumentListInfo *TemplateArgs) {
   if (!TemplateArgs)
-    return new (C) CXXDependentScopeMemberExpr(C, Base, IsArrow, OperatorLoc,
-                                           Qualifier, QualifierRange,
-                                           FirstQualifierFoundInScope,
-                                           Member, MemberLoc);
+    return new (C) CXXDependentScopeMemberExpr(C, Base, BaseType,
+                                               IsArrow, OperatorLoc,
+                                               Qualifier, QualifierRange,
+                                               FirstQualifierFoundInScope,
+                                               Member, MemberLoc);
 
   std::size_t size = sizeof(CXXDependentScopeMemberExpr);
   if (TemplateArgs)
     size += ExplicitTemplateArgumentList::sizeFor(*TemplateArgs);
 
   void *Mem = C.Allocate(size, llvm::alignof<CXXDependentScopeMemberExpr>());
-  return new (Mem) CXXDependentScopeMemberExpr(C, Base, IsArrow, OperatorLoc,
-                                           Qualifier, QualifierRange,
-                                           FirstQualifierFoundInScope,
-                                           Member,
-                                           MemberLoc,
-                                           TemplateArgs);
+  return new (Mem) CXXDependentScopeMemberExpr(C, Base, BaseType,
+                                               IsArrow, OperatorLoc,
+                                               Qualifier, QualifierRange,
+                                               FirstQualifierFoundInScope,
+                                               Member, MemberLoc, TemplateArgs);
 }
 
 Stmt::child_iterator CXXDependentScopeMemberExpr::child_begin() {
@@ -571,12 +572,15 @@ Stmt::child_iterator CXXDependentScopeMemberExpr::child_begin() {
 }
 
 Stmt::child_iterator CXXDependentScopeMemberExpr::child_end() {
+  if (isImplicitAccess())
+    return child_iterator(&Base);
   return child_iterator(&Base + 1);
 }
 
 UnresolvedMemberExpr::UnresolvedMemberExpr(QualType T, bool Dependent,
                                            bool HasUnresolvedUsing,
-                                           Expr *Base, bool IsArrow,
+                                           Expr *Base, QualType BaseType,
+                                           bool IsArrow,
                                            SourceLocation OperatorLoc,
                                            NestedNameSpecifier *Qualifier,
                                            SourceRange QualifierRange,
@@ -584,7 +588,8 @@ UnresolvedMemberExpr::UnresolvedMemberExpr(QualType T, bool Dependent,
                                            SourceLocation MemberLoc,
                                    const TemplateArgumentListInfo *TemplateArgs)
   : Expr(UnresolvedMemberExprClass, T, Dependent, Dependent),
-    Base(Base), IsArrow(IsArrow), HasUnresolvedUsing(HasUnresolvedUsing),
+    Base(Base), BaseType(BaseType), IsArrow(IsArrow),
+    HasUnresolvedUsing(HasUnresolvedUsing),
     HasExplicitTemplateArgs(TemplateArgs != 0),
     OperatorLoc(OperatorLoc),
     Qualifier(Qualifier), QualifierRange(QualifierRange),
@@ -596,7 +601,7 @@ UnresolvedMemberExpr::UnresolvedMemberExpr(QualType T, bool Dependent,
 UnresolvedMemberExpr *
 UnresolvedMemberExpr::Create(ASTContext &C, bool Dependent,
                              bool HasUnresolvedUsing,
-                             Expr *Base, bool IsArrow,
+                             Expr *Base, QualType BaseType, bool IsArrow,
                              SourceLocation OperatorLoc,
                              NestedNameSpecifier *Qualifier,
                              SourceRange QualifierRange,
@@ -610,8 +615,8 @@ UnresolvedMemberExpr::Create(ASTContext &C, bool Dependent,
   void *Mem = C.Allocate(size, llvm::alignof<UnresolvedMemberExpr>());
   return new (Mem) UnresolvedMemberExpr(
                              Dependent ? C.DependentTy : C.OverloadTy,
-                             Dependent, HasUnresolvedUsing, Base, IsArrow,
-                             OperatorLoc, Qualifier, QualifierRange,
+                             Dependent, HasUnresolvedUsing, Base, BaseType,
+                             IsArrow, OperatorLoc, Qualifier, QualifierRange,
                              Member, MemberLoc, TemplateArgs);
 }
 
@@ -620,5 +625,7 @@ Stmt::child_iterator UnresolvedMemberExpr::child_begin() {
 }
 
 Stmt::child_iterator UnresolvedMemberExpr::child_end() {
+  if (isImplicitAccess())
+    return child_iterator(&Base);
   return child_iterator(&Base + 1);
 }