[Bug c++/11811] New: Weird error message with default template arguments

["bangerth at dealii dot org" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11811

           Summary: Weird error message with default template arguments
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bangerth at dealii dot org
                CC: gcc-bugs at gcc dot gnu dot org,gdr at gcc dot gnu dot
                    org

Consider the following code:
-------------------------
void foo(int);

template <typename>
void bar() {
  foo;
}

template void bar<int>();
--------------------------
With present mainline, we get the following message:
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc
x.cc: In function `void bar() [with <template default argument error> = int]':
x.cc:8:   instantiated from here
x.cc:5: warning: statement is a reference, not call, to function `foo(int)'


Note the string "<template default argument error>". That's weird,
because the error is certainly not in the default argument. It
seems to me as if the expression dumper just has a problem here,
but I better leave this judgement to those who know better.

Another weird point: if one removes the declaration of foo(), i.e.
--------------------------------
template <typename>
void bar() {
  foo;
}

template void bar<int>();
--------------------------------
then we get a message that doesn't even say that bar is a template:
g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc
x.cc: In function `void bar()':
x.cc:3: error: `foo' undeclared (first use this function)
x.cc:3: error: (Each undeclared identifier is reported only once for each
   function it appears in.)

That's at best inconsistent.

W.