[Bug c++/52597] New: [C++11] missing diagnostics for invalid use of non-static member function in decltype

["hstong at ca dot ibm.com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52597

             Bug #: 52597
           Summary: [C++11] missing diagnostics for invalid use of
                    non-static member function in decltype
    Classification: Unclassified
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hstong@ca.ibm.com
              Host: powerpc64-unknown-linux-gnu
            Target: powerpc64-unknown-linux-gnu


The following test case shows that GCC allows several ill-formed decltype
constructs with non-static member functions.

Using the last form, SFINAE can be put into play--so wrong overload resolution
and partial specialization matching can be made to occur.

In particular:

bar0 violates N3290 subclause 5.1.1 [expr.prim.general] paragraph 12 regarding
valid uses of an id-expression that denotes a non-static data member or non-
static member function.

The other decltype specifiers violate N3290 subclause 5.2.5 [expr.ref]
paragraph 4 since the non-static member function is not used as the left-hand
operand of a member function call.


### Self-contained source:$ cat illdclty.cc
struct A {
   int zip();

   decltype(zip) bar0;  // invalid use of non-static member function name
      // [expr.prim.general]
   void bar1() {   typedef decltype(this->A::zip) x;   }
      // invalid use of non-static member function name
      // [expr.ref]
   void bar2() {   typedef decltype(A::zip) x;   }
      // invalid use of non-static member function name
      // (same as bar1), see [class.mfct.non-static]
};

typedef decltype(A().zip) x;
      // invalid use of non-static member function name
      // [expr.ref]


### Compiler invocation:$ g++-4.6.0 --std=c++0x illdclty.cc -W -Wall -pedantic
-c


### Compiler output:
(return code 0)


### g++ -v output:$ g++-4.6.0 -v
Using built-in specs.
COLLECT_GCC=g++-4.6.0
COLLECT_LTO_WRAPPER=/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: powerpc64-unknown-linux-gnu
Configured with: ./configure --prefix=/data/gcc --program-suffix=-4.6.0
--disable-libssp --disable-libgcj --enable-version-specific-runtime-libs
--with-cpu=default32 --enable-secureplt --with-long-double-128 --enable-shared
--enable-__cxa_atexit --enable-threads=posix --enable-languages=c,c++,fortran
--with-gmp=/usr/local
Thread model: posix
gcc version 4.6.0 (GCC)