Add an error message with fixit hint for changing '.' to '->'.

This is mainly for attempting to recover in cases where a class provides
a custom operator-> and a '.' was accidentally used instead of '->' when
accessing a member of the object returned by the current object's
operator->.

llvm-svn: 155580

1 files changed, 32 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaExprMember.cpp b/clang/lib/Sema/SemaExprMember.cpp
index 01d5fc65847..81aba6ac0e2 100644
--- a/clang/lib/Sema/SemaExprMember.cpp
+++ b/clang/lib/Sema/SemaExprMember.cpp
@@ -813,8 +813,9 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
                                SourceLocation TemplateKWLoc,
                                NamedDecl *FirstQualifierInScope,
                                LookupResult &R,
-                         const TemplateArgumentListInfo *TemplateArgs,
-                               bool SuppressQualifierCheck) {
+                               const TemplateArgumentListInfo *TemplateArgs,
+                               bool SuppressQualifierCheck,
+                               ActOnMemberAccessExtraArgs *ExtraArgs) {
   QualType BaseType = BaseExprType;
   if (IsArrow) {
     assert(BaseType->isPointerType());
@@ -835,6 +836,32 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
                        ? computeDeclContext(SS, false)
                        : BaseType->getAs<RecordType>()->getDecl());
 
+    if (ExtraArgs) {
+      ExprResult RetryExpr;
+      if (!IsArrow && BaseExpr) {
+        SFINAETrap Trap(*this);
+        ParsedType ObjectType;
+        bool MayBePseudoDestructor = false;
+        RetryExpr = ActOnStartCXXMemberReference(getCurScope(), BaseExpr,
+                                                 OpLoc, tok::arrow, ObjectType,
+                                                 MayBePseudoDestructor);
+        if (RetryExpr.isUsable() && !Trap.hasErrorOccurred()) {
+          CXXScopeSpec TempSS(SS);
+          RetryExpr = ActOnMemberAccessExpr(
+              ExtraArgs->S, RetryExpr.get(), OpLoc, tok::arrow, TempSS,
+              TemplateKWLoc, ExtraArgs->Id, ExtraArgs->ObjCImpDecl,
+              ExtraArgs->HasTrailingLParen);
+        }
+        if (Trap.hasErrorOccurred())
+          RetryExpr = ExprError();
+      }
+      if (RetryExpr.isUsable()) {
+        Diag(OpLoc, diag::err_no_member_overloaded_arrow)
+          << MemberName << DC << FixItHint::CreateReplacement(OpLoc, "->");
+        return RetryExpr;
+      }
+    }
+
     Diag(R.getNameLoc(), diag::err_no_member)
       << MemberName << DC
       << (BaseExpr ? BaseExpr->getSourceRange() : SourceRange());
@@ -1506,9 +1533,11 @@ ExprResult Sema::ActOnMemberAccessExpr(Scope *S, Expr *Base,
       return move(Result);
     }
 
+    ActOnMemberAccessExtraArgs ExtraArgs = {S, Id, ObjCImpDecl, HasTrailingLParen};
     Result = BuildMemberReferenceExpr(Base, Base->getType(),
                                       OpLoc, IsArrow, SS, TemplateKWLoc,
-                                      FirstQualifierInScope, R, TemplateArgs);
+                                      FirstQualifierInScope, R, TemplateArgs,
+                                      false, &ExtraArgs);
   }
 
   return move(Result);