Don't repeat lookup when instantiating resolved member expressions.

Adjust BuildMemberReferenceExpr to perform the inheritance check on implicit
member accesses, which can arise from unqualified lookups and therefore may
reference decls from enclosing class scopes.

Fixes PR 5838.

llvm-svn: 93510

1 files changed, 22 insertions, 14 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index e02dbd6bebd..034accd1c4e 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -1397,7 +1397,9 @@ Sema::BuildImplicitMemberExpr(const CXXScopeSpec &SS,
   return BuildMemberReferenceExpr(ExprArg(*this, This), ThisType,
                                   /*OpLoc*/ SourceLocation(),
                                   /*IsArrow*/ true,
-                                  SS, R, TemplateArgs);
+                                  SS,
+                                  /*FirstQualifierInScope*/ 0,
+                                  R, TemplateArgs);
 }
 
 bool Sema::UseArgumentDependentLookup(const CXXScopeSpec &SS,
@@ -2471,8 +2473,7 @@ Sema::BuildMemberReferenceExpr(ExprArg BaseArg, QualType BaseType,
   } else {
     OwningExprResult Result =
       LookupMemberExpr(R, Base, IsArrow, OpLoc,
-                       SS, FirstQualifierInScope,
-                       /*ObjCImpDecl*/ DeclPtrTy());
+                       SS, /*ObjCImpDecl*/ DeclPtrTy());
 
     if (Result.isInvalid()) {
       Owned(Base);
@@ -2484,13 +2485,15 @@ Sema::BuildMemberReferenceExpr(ExprArg BaseArg, QualType BaseType,
   }
 
   return BuildMemberReferenceExpr(ExprArg(*this, Base), BaseType,
-                                  OpLoc, IsArrow, SS, R, TemplateArgs);
+                                  OpLoc, IsArrow, SS, FirstQualifierInScope,
+                                  R, TemplateArgs);
 }
 
 Sema::OwningExprResult
 Sema::BuildMemberReferenceExpr(ExprArg Base, QualType BaseExprType,
                                SourceLocation OpLoc, bool IsArrow,
                                const CXXScopeSpec &SS,
+                               NamedDecl *FirstQualifierInScope,
                                LookupResult &R,
                          const TemplateArgumentListInfo *TemplateArgs) {
   Expr *BaseExpr = Base.takeAs<Expr>();
@@ -2520,11 +2523,17 @@ Sema::BuildMemberReferenceExpr(ExprArg Base, QualType BaseExprType,
     return ExprError();
   }
 
-  // Diagnose qualified lookups that find only declarations from a
-  // non-base type.  Note that it's okay for lookup to find
-  // declarations from a non-base type as long as those aren't the
-  // ones picked by overload resolution.
-  if (SS.isSet() && CheckQualifiedMemberReference(BaseExpr, BaseType, SS, R))
+  // Diagnose lookups that find only declarations from a non-base
+  // type.  This is possible for either qualified lookups (which may
+  // have been qualified with an unrelated type) or implicit member
+  // expressions (which were found with unqualified lookup and thus
+  // may have come from an enclosing scope).  Note that it's okay for
+  // lookup to find declarations from a non-base type as long as those
+  // aren't the ones picked by overload resolution.
+  if ((SS.isSet() || !BaseExpr ||
+       (isa<CXXThisExpr>(BaseExpr) &&
+        cast<CXXThisExpr>(BaseExpr)->isImplicit())) &&
+      CheckQualifiedMemberReference(BaseExpr, BaseType, SS, R))
     return ExprError();
 
   // Construct an unresolved result if we in fact got an unresolved
@@ -2666,7 +2675,6 @@ Sema::OwningExprResult
 Sema::LookupMemberExpr(LookupResult &R, Expr *&BaseExpr,
                        bool &IsArrow, SourceLocation OpLoc,
                        const CXXScopeSpec &SS,
-                       NamedDecl *FirstQualifierInScope,
                        DeclPtrTy ObjCImpDecl) {
   assert(BaseExpr && "no base expression");
 
@@ -3101,7 +3109,7 @@ Sema::LookupMemberExpr(LookupResult &R, Expr *&BaseExpr,
         << Property->getDeclName();          
 
       return LookupMemberExpr(Res, BaseExpr, IsArrow, OpLoc, SS,
-                              FirstQualifierInScope, ObjCImpDecl);
+                              ObjCImpDecl);
     }
 
     return ExprError(Diag(MemberLoc, diag::err_property_not_found)
@@ -3204,8 +3212,7 @@ Sema::OwningExprResult Sema::ActOnMemberAccessExpr(Scope *S, ExprArg BaseArg,
       DecomposeTemplateName(R, Id);
     } else {
       Result = LookupMemberExpr(R, Base, IsArrow, OpLoc,
-                                SS, FirstQualifierInScope,
-                                ObjCImpDecl);
+                                SS, ObjCImpDecl);
 
       if (Result.isInvalid()) {
         Owned(Base);
@@ -3226,7 +3233,8 @@ Sema::OwningExprResult Sema::ActOnMemberAccessExpr(Scope *S, ExprArg BaseArg,
     }
 
     Result = BuildMemberReferenceExpr(ExprArg(*this, Base), Base->getType(),
-                                      OpLoc, IsArrow, SS, R, TemplateArgs);
+                                      OpLoc, IsArrow, SS, FirstQualifierInScope,
+                                      R, TemplateArgs);
   }
 
   return move(Result);