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try to fix bug #54406
Per [class.access.base]/6, this example is ill-formed:
struct A {
int m;
} a;
struct B : A {};
int n = a.B::m;
... because the object expression a cannot be implicitly converted to B
(because B is not a base class of A). Clang does not diagnose this and accepts
the member access. This opens a hole in the protected member access rules:
struct C {
protected:
int m;
};
struct D : private C {
int get(C &c) { return c.D::m; }
};
This example is invalid for the same reason, but Clang accepts it.
([class.protected]p1, which normally would prevent D from accessing protected
members on a C object that is not a D object, does not apply here because m as
a member of the naming class D is private, not protected.)
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D122460
Files:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaExprMember.cpp
clang/test/CXX/class.access/class.protected/p1.cpp
clang/test/CXX/drs/dr1xx.cpp
clang/test/CXX/expr/expr.prim/expr.prim.general/p8-0x.cpp
clang/test/SemaCXX/member-expr.cpp
clang/test/SemaCXX/qual-id-test.cpp
clang/test/SemaTemplate/typo-dependent-name.cpp
Index: clang/test/SemaTemplate/typo-dependent-name.cpp
===================================================================
--- clang/test/SemaTemplate/typo-dependent-name.cpp
+++ clang/test/SemaTemplate/typo-dependent-name.cpp
@@ -37,9 +37,9 @@
bool f(T other) {
// We can determine that 'inner' does not exist at parse time, so can
// perform typo correction in this case.
- return this->inner<other>::z; // expected-error {{no template named 'inner' in 'Y<T>'; did you mean 'Inner'?}}
+ return this->inner<other>::z; // expected-error {{Y<Q>::Inner<0>' is not a base of 'Y<Q>'}} expected-error {{no template named 'inner' in 'Y<T>'; did you mean 'Inner'?}}
}
};
struct Q { constexpr operator int() { return 0; } };
-void use_y(Y<Q> x) { x.f(Q()); }
+void use_y(Y<Q> x) { x.f(Q()); } // expected-note {{in instantiation of member function 'Y<Q>::f' requested here}}
Index: clang/test/SemaCXX/qual-id-test.cpp
===================================================================
--- clang/test/SemaCXX/qual-id-test.cpp
+++ clang/test/SemaCXX/qual-id-test.cpp
@@ -54,7 +54,7 @@
a.A::sub::x();
a.A::B::base::x();
- a.bad::x(); // expected-error{{'bad::x' is not a member of class 'A::sub'}}
+ a.bad::x(); // expected-error{{'bad' is not a base of 'sub'}}
a->foo();
a->member::foo();
@@ -75,7 +75,7 @@
a->A::sub::x();
a->A::B::base::x();
- a->bad::x(); // expected-error{{'bad::x' is not a member of class 'A::sub'}}
+ a->bad::x(); // expected-error{{'bad' is not a base of 'sub'}}
(*a)->foo();
(*a)->member::foo();
@@ -119,7 +119,7 @@
a.A::B::base::x();
a->A::member::foo();
- a.bad::x(); // expected-error{{'bad::x' is not a member of class 'A::sub'}}
+ a.bad::x(); // expected-error{{'bad' is not a base of 'sub'}}
}
void test_fun5() {
Index: clang/test/SemaCXX/member-expr.cpp
===================================================================
--- clang/test/SemaCXX/member-expr.cpp
+++ clang/test/SemaCXX/member-expr.cpp
@@ -117,8 +117,8 @@
void f(Y *y) {
y->N::X1<int>; // expected-error{{'rdar8231724::N::X1' is not a member of class 'rdar8231724::Y'}}
- y->Z<int>::n; // expected-error{{'rdar8231724::Z<int>::n' is not a member of class 'rdar8231724::Y'}}
- y->template Z<int>::n; // expected-error{{'rdar8231724::Z<int>::n' is not a member of class 'rdar8231724::Y'}}
+ y->Z<int>::n; // expected-error{{'rdar8231724::Z<int>' is not a base of 'Y'}}
+ y->template Z<int>::n; // expected-error{{'rdar8231724::Z<int>' is not a base of 'Y'}}
#if __cplusplus <= 199711L // C++03 or earlier modes
// expected-warning@-2{{'template' keyword outside of a template}}
#endif
Index: clang/test/CXX/expr/expr.prim/expr.prim.general/p8-0x.cpp
===================================================================
--- clang/test/CXX/expr/expr.prim/expr.prim.general/p8-0x.cpp
+++ clang/test/CXX/expr/expr.prim/expr.prim.general/p8-0x.cpp
@@ -30,7 +30,7 @@
decltype(outer::middle::inner()) a;
void scope() {
- a.decltype(outer::middle())::mfunc(); // expected-error{{'PR10127::outer::middle::mfunc' is not a member of class 'decltype(outer::middle::inner())'}}
+ a.decltype(outer::middle())::mfunc(); // expected-error{{PR10127::outer::middle' is not a base of 'inner'}}
a.decltype(outer::middle::inner())::func();
a.decltype(outer::middle())::inner::func();
a.decltype(outer())::middle::inner::func();
Index: clang/test/CXX/drs/dr1xx.cpp
===================================================================
--- clang/test/CXX/drs/dr1xx.cpp
+++ clang/test/CXX/drs/dr1xx.cpp
@@ -477,7 +477,7 @@
namespace dr141 { // dr141: yes
template<typename T> void f();
- template<typename T> struct S { int n; }; // expected-note {{'::dr141::S<int>::n' declared here}}
+ template<typename T> struct S { int n; };
struct A : S<int> {
template<typename T> void f();
template<typename T> struct S {};
@@ -485,7 +485,7 @@
struct B : S<int> {} b;
void g() {
a.f<int>();
- (void)a.S<int>::n; // expected-error {{no member named 'n' in 'dr141::A::S<int>'; did you mean '::dr141::S<int>::n'?}}
+ (void)a.S<int>::n; // expected-error {{'dr141::A::S<int>' is not a base of 'A'}}
#if __cplusplus < 201103L
// expected-error@-2 {{ambiguous}}
// expected-note@-11 {{lookup from the current scope}}
Index: clang/test/CXX/class.access/class.protected/p1.cpp
===================================================================
--- clang/test/CXX/class.access/class.protected/p1.cpp
+++ clang/test/CXX/class.access/class.protected/p1.cpp
@@ -323,31 +323,32 @@
namespace test9 {
class A { // expected-note {{member is declared here}}
- protected: int foo(); // expected-note 4 {{declared}} expected-note 3 {{can only access this member on an object of type}} expected-note 2 {{member is declared here}}
+ protected: int foo(); // expected-note 2 {{can only access this member on an object of type 'test9::D'}} \
+ // expected-note 2 {{member is declared here}}
};
class B : public A { // expected-note {{member is declared here}}
friend class D;
};
- class C : protected B { // expected-note {{declared}} \
- // expected-note 7 {{constrained}}
+ class C : protected B { // expected-note 5 {{constrained by protected inheritance here}} expected-note {{declared protected here}}
+
};
class D : public A {
static void test(A &a) {
a.foo(); // expected-error {{'foo' is a protected member}}
a.A::foo(); // expected-error {{'foo' is a protected member}}
- a.B::foo(); // expected-error {{'foo' is a protected member}}
- a.C::foo(); // expected-error {{'foo' is a protected member}}
- a.D::foo(); // expected-error {{'foo' is a protected member}}
+ a.B::foo(); // expected-error {{'test9::B' is not a base of 'A'}}
+ a.C::foo(); // expected-error {{'test9::C' is not a base of 'A'}}
+ a.D::foo(); // expected-error {{'test9::D' is not a base of 'A'}}
}
static void test(B &b) {
b.foo();
b.A::foo();
b.B::foo(); // accessible as named in A
- b.C::foo(); // expected-error {{'foo' is a protected member}}
+ b.C::foo(); // expected-error {{'test9::C' is not a base of 'B'}}
}
static void test(C &c) {
@@ -362,8 +363,8 @@
static void test(D &d) {
d.foo();
d.A::foo();
- d.B::foo();
- d.C::foo(); // expected-error {{'foo' is a protected member}}
+ d.B::foo(); // expected-error {{'test9::B' is not a base of 'D'}}
+ d.C::foo(); // expected-error {{'test9::C' is not a base of 'D'}}
}
};
}
Index: clang/lib/Sema/SemaExprMember.cpp
===================================================================
--- clang/lib/Sema/SemaExprMember.cpp
+++ clang/lib/Sema/SemaExprMember.cpp
@@ -680,6 +680,22 @@
<< DC << SS.getRange();
return true;
}
+ // fix bug #54406
+ // Per [class.access.base]/6, this example is ill-formed:
+ // struct A {
+ // int m;
+ // } a;
+ // struct B : A {};
+ // int n = a.B::m;
+ if (BaseExpr && isa<CXXRecordDecl>(DC) && isa<CXXRecordDecl>(RDecl)) {
+ CXXRecordDecl *SRecord = cast<CXXRecordDecl>(DC)->getCanonicalDecl();
+ CXXRecordDecl *RRecord = cast<CXXRecordDecl>(RDecl)->getCanonicalDecl();
+ if (SRecord != RRecord && RRecord->isProvablyNotDerivedFrom(SRecord)) {
+ SemaRef.Diag(R.getNameLoc(), diag::err_qualified_member_not_base)
+ << DC << RDecl << SS.getRange();
+ return true;
+ }
+ }
}
// The record definition is complete, now look up the member.
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1798,6 +1798,8 @@
"lookup from the current scope refers here">;
def err_qualified_member_nonclass : Error<
"qualified member access refers to a member in %0">;
+def err_qualified_member_not_base : Error<
+ "%0 is not a base of %1">;
def err_incomplete_member_access : Error<
"member access into incomplete type %0">;
def err_incomplete_type : Error<
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