http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52761
Bug #: 52761
Summary: [C++11] Missing diagnostic for opaque unscoped enum
declaration without base
Classification: Unclassified
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: hst...@ca.ibm.com
Host: powerpc64-unknown-linux-gnu
Target: powerpc64-unknown-linux-gnu
### Self-contained source:$ cat enumredecl.cc
enum E { X };
enum E; // illegal
### Analysis:
For C++2011, subclause 7.2 [dcl.enum] paragraph 2 says:
An opaque-enum-declaration declaring an unscoped enumeration shall not omit the
enum-base.
The code is also invalid under C++03.
The "redeclaration" does not meet the requirements in C++03 clause 7 [dcl.dcl]
paragraph 3 for the omission of the init-declarator-list in a simple-
declaration. Namely, it is not a class definition or declaration and is not a
enum definition.
It also fails to requirements in subclause 7.1.5.3 [dcl.type.elab] paragraph 1
for an elaborated-type-specifier that is the sole constituent of a declaration.
Namely, it is neither an explicit specialization, explicit instantiation, class
declaration nor friend class declaration.
### Compiler invocations:
$ g++-4.6.0 --std='c++0x' -Wall -W -pedantic enumredecl.cc -c
$ g++-4.6.0 --std='c++98' -Wall -W -pedantic enumredecl.cc -c
### Compiler output (both cases):
(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)
