GCC compilation error for template template parameters

From:

Adam Badura <abadura@o2.pl>

Newsgroups:

comp.lang.c++.moderated

Date:

Wed, 6 Feb 2008 20:13:12 CST

Message-ID:

<168f3456-fbb9-4bfd-a152-6d3836f43a2f@m34g2000hsb.googlegroups.com>

Following simple code:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

template< template< typename > class T1 >
struct OuterType
{
    template< typename T2 >
    struct InnerType {};
};

template< template< typename > class T >
struct TestType : public OuterType< OuterType< T >::InnerType > {};

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

while being compiled with GCC 3.4.4 (Windows, Cygwin) with no compiler
options produces following error:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

gpp.cpp:10: error: type/value mismatch at argument 1 in template
parameter list for `template<template<class> class T1> struct
OuterType'
gpp.cpp:10: error: expected a class template, got
`OuterType<T1>::InnerType'

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

MS VS 2008 for the same code does not generate any error (nor
warning).

Adding "typename" before "OuterType< T >::InnerType" does not change
anything (on both compilers) and seems wrong to me anyway.

Whats wrong with that code? Or is it a bug in GCC?

Adam Badura

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