IV56872: NO BEST MATCH FOR METHOD WITH THROW SPECIFIER

XL C/C++ for AIX Fix Pack 11 (February 2015 PTF) for 12.1
XL C/C++ for AIX Fix Pack 12 (May 2015 PTF) for 12.1
XL C/C++ for AIX Fix Pack 13 (August 2015 Update) for 12.1
XL C/C++ for AIX Fix Pack 14 (December 2015 Update) for 12.1
XL C/C++ for AIX Fix Pack 15 (April 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 16 (July 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 17 (November 2016 Update) for 12.1
XL C/C++ for AIX Fix Pack 18 (February 2017 Update) for 12.1
XL C/C++ for AIX Fix Pack 19 (August 2017 Update) for 12.1
XL C/C++ for AIX Fix Pack 20 (March 2018 Update) for 12.1
XL C/C++ for AIX Fix Pack 9 (July 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 10 (October 2014 PTF) for 12.1
XL C/C++ for AIX Fix Pack 21 (January 2019 Update) for 12.1

APAR status

• Closed as program error.

Error description

• The compiler is outputting an error message that it can not find
  a match for a method in a parent class, when a method with the
  same name is found in the child class, or vice versa.
  
  The error is triggered by one (but not both) of the methods
  using a 'throw()' exception specifier.
  
  
      ==== TEST CASE ===
  
  class A1 {
    public:
      void test(int) throw();
  };
  class A2: public A1 {
    public:
      using A1::test;
      void test(int);
      void func() { test(1); }
  };
  
  
  $ xlC -c test.cpp
  "test.cpp", line 9.19: 1540-0219
      (S) The call to "test" has no best match.
  "test.cpp", line 9.19: 1540-1230
      (I) Argument number 1 is the implicit "this" argument.
  "test.cpp", line 9.24: 1540-1229
      (I) Argument number 2 is an rvalue of type "int".
  "test.cpp", line 3.10: 1540-1202
      (I) No candidate is better than "A1::test(int)".
  "test.cpp", line 9.19: 1540-1231
      (I) The conversion from argument number 1 to "A2 &" uses
          "the identity conversion".
  "test.cpp", line 9.24: 1540-1231
      (I) The conversion from argument number 2 to "int" uses "the
          identity conversion".
  "test.cpp", line 8.10: 1540-1202
      (I) No candidate is better than "A2::test(int)".
  "test.cpp", line 9.19: 1540-1231
      (I) The conversion from argument number 1 to "A2 &" uses
          "the identity conversion".
  "test.cpp", line 9.24: 1540-1231
      (I) The conversion from argument number 2 to "int" uses "the
          identity conversion".
  $
  

Local fix

• Remove the 'throw()' exception specifier, or add one to the
  other method, in either the parent or child classes.
  

Problem summary

• PROBLEM DESCRIPTION:
  The compiler was not able to handle the throw() specifier
  properly in overload resolution.
  
  USERS AFFECTED:
  Users with the throw() specifier in their class with another
  function with same name.
  

Problem conclusion

• The compiler can now correctly handle throw specifiers.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  LI77966

Fix information

• Fixed component name

  XL C/C++ FOR AI

• Fixed component ID

  5725C7200

Applicable component levels