LI75087: CLASS TEMPLATE NOT FINDING CLASS NAME

October 2009 Update for XL C/C++ for Linux, V10.1
June 2011 Update for XL C/C++ for Linux, V10.1
XL C/C++ for Linux Fix Pack 8 (January 2014 Update) for 10.1
August 2010 Update for XL C/C++ for Linux, V10.1
January 2011 Update for XL C/C++ for Linux, V10.1
January 2012 Update for XL C/C++ for Linux, V10.1
July 2012 Update for XL C/C++ for Linux, V10.1

APAR status

• Closed as program error.

Error description

• A class template takes a class type as it's first parameter, and
  an int as it's second parameter.  The int's default value is
  dependant on the class type of the first parameter (in the
  following testcase the sizeof function is used).  When
  instantiating the class template with a class type that is
  defined lower in the source, the compiler reports that the class
  is undefined.
  
  =====  Error   =====
  "test.C", line 1.31: 1540-1109 (S) The use of undefined class
  "SomeClass" is not valid.
  
  ===== TESTCASE =====
  template <class T, int myInt = sizeof(T)>
  class TestClass
  {};
  
  class SomeClass
  {};
  
  int main()
  {
   TestClass<SomeClass> test;
  }
  

Local fix

• A forward definition of the class does not solve the issue.
  Moving the full class above the template class solves the
  problem.
  

Problem summary

• USER AFFECTED:
  The problem may appear when a sizeof expression is used in a
  default template parameter, and that sizeof expression
  depends on the previous template parameters.
  
  PROBLEM DESCRIPTION:
  The compiler was resolving the name at the wrong location.
  

Problem conclusion

• The compiler now uses the correct location to resolve
  the name.
  

Temporary fix

Comments

APAR Information

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

  IZ50126

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

Fix information

• Fixed component name

  XL C/C++ RHEL52

• Fixed component ID

  5724U8310

Applicable component levels

• RA10 PSN IZ50126

     UP06/09/13