[Sema] Call to deleted functions are supposed to be verboten

[davide]

Summary

I originally tried to fix this in SemaExpr (ActOnCallExpr), putting this check just before BuildCallToMemberFunction() call, but eventaully convinced myself SemaOverload should be the right place to fix.

Thanks,

Davide

[mclow.lists]

I don't spend a lot of time on the internals of clang; but this looks reasonable to me.

[davide]

Addressing comments.

[rsmith]

lib/Sema/SemaOverload.cpp

11608 ↗

(On Diff #30288)

This check should happen when we build the MemberExpr, not when we use it. It looks like the bug is in Sema::BuildMemberReferenceExpr, at around line 1050 of SemaExprMember.cpp:

bool ShouldCheckUse = true;
if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MemberDecl)) {
  // Don't diagnose the use of a virtual member function unless it's
  // explicitly qualified.
  if (MD->isVirtual() && !SS.isSet())
    ShouldCheckUse = false;
}

// Check the use of this member.
if (ShouldCheckUse && DiagnoseUseOfDecl(MemberDecl, MemberLoc))
  return ExprError();

This is wrong: we should DiagnoseUseOfDecl (including diagnosing the use of a deleted function) even for a virtual function. Which tests fail if we unconditionally DiagnoseUseOfDecl here?

cfe/trunk/lib/Sema/SemaExprMember.cpp

if (!BaseExpr) {
 
     SourceLocation Loc = R.getNameLoc();
     if (SS.getRange().isValid())
       Loc = SS.getRange().getBegin();
     CheckCXXThisCapture(Loc);
     BaseExpr = new (Context) CXXThisExpr(Loc, BaseExprType,/*isImplicit=*/true);
   }
 
-  bool ShouldCheckUse = true;
-  if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MemberDecl)) {
-    // Don't diagnose the use of a virtual member function unless it's
-    // explicitly qualified.
-    if (MD->isVirtual() && !SS.isSet())
-      ShouldCheckUse = false;
-  }
-
   // Check the use of this member.
-  if (ShouldCheckUse && DiagnoseUseOfDecl(MemberDecl, MemberLoc))
+  if (DiagnoseUseOfDecl(MemberDecl, MemberLoc))
     return ExprError();
 
   if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl))
     return BuildFieldReferenceExpr(*this, BaseExpr, IsArrow, OpLoc, SS, FD,
                                    FoundDecl, MemberNameInfo);
 
   if (MSPropertyDecl *PD = dyn_cast<MSPropertyDecl>(MemberDecl))
     return BuildMSPropertyRefExpr(*this, BaseExpr, IsArrow, SS, PD,

cfe/trunk/test/SemaCXX/attr-deprecated.cpp

void A::h(A* a)
   f();
   a->f();
   
   (void)b;
   (void)a->b;
 }
 
 struct B {
-  virtual void f() __attribute__((deprecated)); // expected-note 4 {{'f' has been explicitly marked deprecated here}}
+  virtual void f() __attribute__((deprecated)); // expected-note 6 {{'f' has been explicitly marked deprecated here}}
   void g();
 };
 
 void B::g() {
-  f();
+  f(); // expected-warning{{'f' is deprecated}}
   B::f(); // expected-warning{{'f' is deprecated}}
 }
 
 struct C : B {
   virtual void f();
   void g();
 };
 
 void C::g() {
   f();
   C::f();
   B::f(); // expected-warning{{'f' is deprecated}}
 }
 
 void f(B* b, C *c) {
-  b->f();
+  b->f(); // expected-warning{{'f' is deprecated}}
   b->B::f(); // expected-warning{{'f' is deprecated}}
   
   c->f();
   c->C::f();
   c->B::f(); // expected-warning{{'f' is deprecated}}
 }
 
 struct D {
   virtual void f() __attribute__((deprecated));
 };
 
-void D::f() { }
+void D::f() { } // expected-note{{'f' has been explicitly marked deprecated here}}
 
 void f(D* d) {
-  d->f();
+  d->f(); // expected-warning{{'f' is deprecated}}
 }
 
 
 // Overloaded namespace members.
 namespace test1 {
   void foo(int) __attribute__((deprecated)); // expected-note {{'foo' has been explicitly marked deprecated here}}
   void test1() { foo(10); } // expected-warning {{deprecated}}
   void foo(short) __attribute__((deprecated)); // expected-note {{'foo' has been explicitly marked deprecated here}}

cfe/trunk/test/SemaCXX/deleted-function-access.cpp

+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+
+struct S {
+    virtual void f() = delete; //expected-note{{'f' has been explicitly marked deleted here}}
+    void g() { f(); } //expected-error{{attempt to use a deleted function}}
+};