[Bug c++/60742] New: ill-formed declarator (array) in selection statement not caught appropriately

[filip.roseen at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60742

            Bug ID: 60742
           Summary: ill-formed declarator (array) in selection statement
                    not caught appropriately
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: filip.roseen at gmail dot com

Created attachment 32527
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32527&action=edit
testcase.cpp

int main () {
  if (int a[3] = {1,2,3}) {
    (void)a;
  }
}


-------------------------------------------------------------

[stmt.select]p2:

  > The rules for conditions apply both to selction-statements and to
  > the for and while statements (6.5) __The declarator shall not
  > specify a function or an array.__ If the auto type-specifier appears
  > in the decl-specifier-seq, the type of the identifier being
  > declared is deduced from the initializer as described in 7.1.6.4.

-------------------------------------------------------------

H20:/tmp% g++ -std=c++11 -pedantic-errors testcase.cpp;      
H20:/tmp% g++ -std=c++11 -pedantic-errors -Waddress testcase.cpp;
testcase.cpp: In function ‘int main()’:
testcase.cpp:2:25: warning: the address of ‘a’ will always evaluate as ‘true’
[-Waddress]
   if (int a[3] = {1,2,3}) {

-------------------------------------------------------------

As seen above a diagnostic is only issued if we do `-Waddress` (or some warning
flag that includes the mentioned one).

The problem isn't actually with the address of `a` always evaluting to `true`,
the major problem is that this kind of code is ill-formed; gcc should therefore
reject it.

[ Note: `clang` and `icc` both handles this correctly (ie. rejects it) ]