IZ67449: MISLEADING TEMPLATE ERROR MESSAGE

October 2010 PTF for XL C/C++ for AIX, V10.1
May 2012 PTF for XL C/C++ for AIX, V10.1
January 2013 PTF for XL C/C++ for AIX, V10.1
XL C/C++ for AIX Fix Pack 18 (July 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 19 (October 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 21 (October 2015 PTF) for 10.1
March 2010 PTF for XL C/C++ for AIX, V10.1
April 2010 PTF for XL C/C++ for AIX, V10.1
June 2010 PTF for XL C/C++ for AIX, V10.1
May 2011 PTF for XL C/C++ for AIX, V10.1
October 2011 PTF for XL C/C++ for AIX, V10.1
February 2012 PTF for XL C/C++ for AIX, V10.1
September 2012 PTF for XL C/C++ for AIX, V10.1
XL C/C++ for AIX Fix Pack 20 (October 2014 PTF) for 10.1

APAR status

• Closed as program error.

Error description

• The following test case compiles with an error message on V10.1
  xlC.
  
  
  "test1.cpp", line 7.15: 1540-0236 (S) The constructor
  initializer is
  unexpected.  All bases and members have been initialized.
  
  But it compiles clean on V9, V8, and V7 xlC.
  
  It also compiles clean on Sun's CC compilers.
  
  With g++, the test case gives another error:
  
  test1.cpp: In constructor `B::B(int)':
  test1.cpp:7: error: class `B' does not have any field named `A'
  
  Is the test case ill-formed?
  
  But nonetheless, the error message from XLC++ is very
  confusing.
  
  
  ===== TESTCASE:
  //cat test1.cpp:
  
  template <class T>
  struct A {
    A () { }
    A (const T&) { }
  };
  struct B : public A<int> {
    B (int v) : A(v) { } // diagnostic here is very misleading
  };
  B f () {
    return 5;
  }
  

Local fix

• Change
  B (int v) : A(v) { } // diagnostic here is very misleading
  
  to:
  B (int v) : A<int>(v) { }
  

Problem summary

• USER AFFECTED:
  Users attempting to use the name of template base class
  without template arguments in the derived class
  - specifically in a constructor initializer list.
  
  PROBLEM DESCRIPTION:
  The behaviour for injected names has been clarified
  in the C++ standard so that this syntax is no longer
  permitted, however the compiler message is not useful.
  

Problem conclusion

• Message now emitted is:
  'a.cpp', line 7.15: 1540-1113
  (S) The class template name 'A' must be followed by a < in this
  context.
  

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:

  LI75566 LI75597

Fix information

• Fixed component name

  XL C++ AIX

• Fixed component ID

  5724U8100

Applicable component levels