IV67337: COMPILE TIME ERROR RELATED TO INITIALIZATION AND LVALUE CONVERSION

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 21 (January 2019 Update) for 12.1

APAR status

• Closed as program error.

Error description

• The compiler issues an error message for the following test
  case:
  
  ===== COMPILE COMMAND:
  xlC_r -q32 -qthreaded -qalias=ansi -qlanglvl=extended0x -c
  test.cpp
  
  ===== TESTCASE:
  $ cat test.cpp
  template<typename TFrom, typename TTo = TFrom>
  TTo
  templateFunction(TFrom from)
  {
  return static_cast<TTo>(from);
  }
  
  int main()
  {
  long long value = templateFunction<long long>(55);
  return (value == 55);
  }
  $
  
  
  ===== ACTUAL OUTPUT:
  $
  /gsa/tlbgsa/projects/x/xlcmpbld/run/vacpp/121_com/aix/daily/late
  st/bin/xlC_r -q32 -qthreaded -qalias=ansi -qlanglvl=extended0x
  -c test.cpp
  "test.cpp", line 10.46: 1540-2465 (S) An object or reference of
  type "long long" cannot be initialized with a prvalue of type
  "TFrom".
  "test.cpp", line 5.25: 1540-2463 (S) An lvalue expression of
  type "long long" cannot be converted to type "TFrom".
  "test.cpp", line 5.25: 1540-0218 (I) The call does not match any
  parameter list for "TFrom::TFrom".
  "test.cpp", line 1.10: 1540-1283 (I) "implicit
  TFrom::TFrom(const TFrom &)" is not a viable candidate.
  "test.cpp", line 5.25: 1540-2463 (I) An lvalue expression of
  type "long long" cannot be converted to type "const TFrom &".
  "test.cpp", line 3.1: 1540-0700 (I) The previous message was
  produced while processing "templateFunction<long
  long,TFrom>(long long)".
  "test.cpp", line 8.5: 1540-0700 (I) The previous message was
  produced while processing "main()".
  $
  
  
  ===== EXPECTED OUTPUT:
  Clean compile.
  

Local fix

• N/A
  

Problem summary

• USERS AFFECTED:
  Users how have initialization and lvalue conversions in their
  code may be affected by this issue.
  
  PROBLEM DESCRIPTION:
  The compiler results in a missing template argument
  substitution on default template argument for function
  templates; causig a compile time error.
  

Problem conclusion

• The compiler has been fixed to allow function template default
  arguments to also contain template parameters.
  

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:

  LI78471 IV72799

Fix information

• Fixed component name

  XL C/C++ FOR AI

• Fixed component ID

  5725C7200

Applicable component levels