[Bug c++/54948] template unnecessarily displayed as "A< template-parameter-1-1 >" not "A<T>"

["manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54948

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #2 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2013-04-20 12:03:29 UTC ---
There are several "bugs" in this case. The first one is that we consider that
the type of:

template<typename> struct A

is "struct A< <template-parameter-1-1> >". It would be nicer to print something
like "struct A<typename>" or "struct A<>". Clang never needs to print made up
names.

The second bug is that I think we record T when parsing, but later we drop it.
I wasn't able to find when we drop it. There is a lot going on between the
moment we parse T and the moment we parse {, so it is rather difficult to
figure out. Stepping in the parser is rather frustrating.

I am afraid that the only person that may know what is going or where to look
is Jason. There is lookup_template_class, but by the time we call it, we
already dropped T (or so it seems to me, maybe it is recorded somewhere else).
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Subject: [Bug c++/54948] template unnecessarily displayed as "A< template-parameter-1-1 >" not "A<T>"
Date: Sat, 20 Apr 2013 12:06:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54948

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2013-04-20 12:06:10 UTC ---
BTW, the parser may benefit by marking some functions with "skip" to help
debugging. All the cp_lexer_peek_* are useless to step into.
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Subject: [Bug c++/57012] New: pretty-printer does not handle well template parameter packs
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW012

             Bug #: 57012
           Summary: pretty-printer does not handle well template parameter
                    packs
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: manu@gcc.gnu.org


/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:2:40: error:
parameter pack '<template-parameter-1-1>' must be at the end of the template
parameter list
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:7:11: error:
type/value mismatch at argument 1 in template parameter list for
'template<<declaration error>, class> struct A'
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:7:11: error:
expected a constant of type '<type error>', got 'int'
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:7:14: error:
invalid type in declaration before ';' token
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:8:11: error:
type/value mismatch at argument 1 in template parameter list for
'template<<declaration error>, class> struct A'
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:8:11: error:
expected a constant of type '<type error>', got 'char'
/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:8:14: error:
invalid type in declaration before ';' token

Clang++ by comparison:

/home/manuel/test3/src/gcc/testsuite/g++.dg/cpp0x/pr31432.C:2:10: error:
template parameter pack must be the last template parameter
template<typename..., typename> struct A // { dg-error "parameter pack" }
         ^