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->.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155580 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 113a8fc3e540456524d05e8a2178d008616c97c3..f9fb2bb4fbda3e4552308ff2ba8b561db21e7d03 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3641,6 +3641,8 @@ def warn_subscript_is_char : Warning<"array subscript is of type 'char'">,
 
 def err_typecheck_incomplete_tag : Error<"incomplete definition of type %0">;
 def err_no_member : Error<"no member named %0 in %1">;
+def err_no_member_overloaded_arrow : Error<
+  "no member named %0 in %1; did you mean to use '->' instead of '.'?">;
 
 def err_member_not_yet_instantiated : Error<
   "no member %0 in %1; it has not yet been instantiated">;

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 6012c5664e724d11a0051348deb37903f777b25f..252ea5b6d0740b1900fd1a42caf8138a9ec433a3 100644 (file)
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -2703,6 +2703,18 @@ public:
                                 const DeclarationNameInfo &NameInfo,
                                 const TemplateArgumentListInfo *TemplateArgs);
 
+  // This struct is for use by ActOnMemberAccess to allow
+  // BuildMemberReferenceExpr to be able to reinvoke ActOnMemberAccess after
+  // changing the access operator from a '.' to a '->' (to see if that is the
+  // change needed to fix an error about an unknown member, e.g. when the class
+  // defines a custom operator->).
+  struct ActOnMemberAccessExtraArgs {
+    Scope *S;
+    UnqualifiedId &Id;
+    Decl *ObjCImpDecl;
+    bool HasTrailingLParen;
+  };
+
   ExprResult BuildMemberReferenceExpr(Expr *Base, QualType BaseType,
                                       SourceLocation OpLoc, bool IsArrow,
                                       const CXXScopeSpec &SS,
@@ -2710,7 +2722,8 @@ public:
                                       NamedDecl *FirstQualifierInScope,
                                       LookupResult &R,
                                  const TemplateArgumentListInfo *TemplateArgs,
-                                      bool SuppressQualifierCheck = false);
+                                      bool SuppressQualifierCheck = false,
+                                     ActOnMemberAccessExtraArgs *ExtraArgs = 0);
 
   ExprResult PerformMemberExprBaseConversion(Expr *Base, bool IsArrow);
   ExprResult LookupMemberExpr(LookupResult &R, ExprResult &Base,

diff --git a/lib/Sema/SemaExprMember.cpp b/lib/Sema/SemaExprMember.cpp
index 01d5fc658478eb291a6e1c9de1e2cdc80695b220..81aba6ac0e2be453767c6d1e41db65777953a1a0 100644 (file)
--- a/lib/Sema/SemaExprMember.cpp
+++ b/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);

diff --git a/test/FixIt/fixit.cpp b/test/FixIt/fixit.cpp
index ac1fb6397f391e8ff47e9e8526637a738883893d..e6609d8a6c7fd7cce859592f804df71e89886b42 100644 (file)
--- a/test/FixIt/fixit.cpp
+++ b/test/FixIt/fixit.cpp
@@ -217,3 +217,26 @@ class Foo {
 };
 void Foo::SetBar(Bar bar) { bar_ = bar; } // expected-error {{must use 'enum' tag to refer to type 'Bar' in this scope}}
 }
+
+namespace arrow_suggest {
+
+template <typename T>
+class wrapped_ptr {
+ public:
+  wrapped_ptr(T* ptr) : ptr_(ptr) {}
+  T* operator->() { return ptr_; }
+ private:
+  T *ptr_;
+};
+
+class Worker {
+ public:
+  void DoSomething();
+};
+
+void test() {
+  wrapped_ptr<Worker> worker(new Worker);
+  worker.DoSomething(); // expected-error {{no member named 'DoSomething' in 'arrow_suggest::wrapped_ptr<arrow_suggest::Worker>'; did you mean to use '->' instead of '.'?}}
+}
+
+} // namespace arrow_suggest

diff --git a/test/SemaCXX/arrow-operator.cpp b/test/SemaCXX/arrow-operator.cpp
index 6535a0a2f20185404d5b89d2d1bdcd6f38f45a76..173ff729fc1b998f9e151f1cfb372ee0c4f49d21 100644 (file)
--- a/test/SemaCXX/arrow-operator.cpp
+++ b/test/SemaCXX/arrow-operator.cpp
@@ -36,3 +36,31 @@ void f()
    Line_Segment(node1->Location()); // expected-error {{not a structure or union}}
 }
 }
+
+
+namespace arrow_suggest {
+
+template <typename T>
+class wrapped_ptr {
+ public:
+  wrapped_ptr(T* ptr) : ptr_(ptr) {}
+  T* operator->() { return ptr_; }
+  void Check(); // expected-note {{'Check' declared here}}
+ private:
+  T *ptr_;
+};
+
+class Worker {
+ public:
+  void DoSomething();
+  void Chuck();
+};
+
+void test() {
+  wrapped_ptr<Worker> worker(new Worker);
+  worker.DoSomething(); // expected-error {{no member named 'DoSomething' in 'arrow_suggest::wrapped_ptr<arrow_suggest::Worker>'; did you mean to use '->' instead of '.'?}}
+  worker.DoSamething(); // expected-error {{no member named 'DoSamething' in 'arrow_suggest::wrapped_ptr<arrow_suggest::Worker>'}}
+  worker.Chuck(); // expected-error {{no member named 'Chuck' in 'arrow_suggest::wrapped_ptr<arrow_suggest::Worker>'; did you mean 'Check'?}}
+}
+
+} // namespace arrow_suggest