[cfe-dev] Bug with pointer to const member function

[Benoit Belley]

Hi Everyone,

It seems that Clang fails to report an error when applying a pointer to a const member function to non-const reference or pointer as demonstrated by the following code example:

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class ClassA {};

typedef void (ClassA::*PtrToMem)();
typedef void (ClassA::*PtrToConstMem)() const;

void foo(
  ClassA a,
  const ClassA& a_const,
  ClassA* ap,
  const ClassA* ap_const,
  PtrToMem ptr_to_mem,
  PtrToConstMem ptr_to_const_mem
  
) {
  (a.*ptr_to_mem)();
  (a.*ptr_to_const_mem)();

  (a_const.*ptr_to_mem)();          // expected-error{{invalid conversion from 'const ClassA*' to 'ClassA*'}}
  (a_const.*ptr_to_const_mem)();

  (ap->*ptr_to_mem)();
  (ap->*ptr_to_const_mem)(); 

  (ap_const->*ptr_to_mem)();        // expected-error{{invalid conversion from 'const ClassA*' to 'ClassA*'}}
  (ap_const->*ptr_to_const_mem)();
}
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$ llvm/Debug+Asserts/bin/clang++ -c ptr_to_const_mem_bug.cpp
$
-----------------------------------------------------------------------------------------------------


Is this a known bug ?

I am currently using the SVN revision 114947 of clang.


Note that both the GNU g++ compiler and the Intel C++ compiler are properly reporting the errors:

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$ g++ -c ptr_to_const_mem_bug.cpp
ptr_to_const_mem_bug.cpp: In function 'void foo(ClassA, const ClassA&, ClassA*, const ClassA*, void (ClassA::*)(), void (ClassA::*)()const)':
ptr_to_const_mem_bug.cpp:18: error: invalid conversion from 'const ClassA*' to 'ClassA*'
ptr_to_const_mem_bug.cpp:24: error: invalid conversion from 'const ClassA*' to 'ClassA*’
$ icpc -c ptr_to_const_mem_bug.cpp
ptr_to_const_mem_bug.cpp(18): error: the object has cv-qualifiers that are not compatible with the member function
            object type is: const ClassA
    (a_const.*ptr_to_mem)();          // expected-error{{invalid conversion from 'const ClassA*' to 'ClassA*'}}
     ^

ptr_to_const_mem_bug.cpp(24): error: the object has cv-qualifiers that are not compatible with the member function
            object type is: const ClassA
    (ap_const->*ptr_to_mem)();        // expected-error{{invalid conversion from 'const ClassA*' to 'ClassA*'}}
     ^

compilation aborted for ptr_to_const_mem_bug.cpp (code 2)
$
-----------------------------------------------------------------------------------------------------


Cheers,
Benoit   

 
Benoit Belley
Sr Principal Developer
M&E-Product Development Group    
 
Autodesk Canada Inc. 
10 Rue Duke
Montreal, Quebec  H3C 2L7 
Canada