middle-end/10065: gcc/g++ issues error instead of warning on non-ISO array assignment.

middle-end/10065: gcc/g++ issues error instead of warning on non-ISO array assignment.

[arthur.baldwin]

>Number:         10065
>Category:       middle-end
>Synopsis:       gcc/g++ issues error instead of warning on non-ISO array assignment.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Thu Mar 13 20:36:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Art Baldwin
>Release:        output from "gcc -v":  Reading specs from /opt/gcc-3.2.2/lib/gcc-lib/i686-pc-linux-gnu/3.2.2/specs; Configured with: ../configure --prefix=/opt/gcc-3.2.2; Thread model: posix; gcc version 3.2.2
>Organization:
>Environment:
output from "uname -a":  Linux gca20.gdds.com 2.4.18-18.7.xbigmem #1 SMP Wed Nov 13 18:24:15 EST 2002 i686 unknown
>Description:
Couldn't compile legacy code that used gcc feature allowing direct array copy.  Compiler issued error (not warning) for non-ISO array copy.  In same compilation unit, the compiler ignored a typedef using non-ISO variable length array definition.  But with -pedantic flag, compiler issues expected warnings for both the array assignment and the variable length array, and compilation completes successfully.

No such problem occurs using gcc/g++ 2.95.

==> compilation fails with -Wall, but doesn't seem to care about the variable length array (not even a warning)
gcc -Wall -o arrayTest arrayTest.ii
arrayTest.cc: In function `int main()':
arrayTest.cc:19: ISO C++ forbids assignment of arrays
arrayTest.cc:28: ISO C++ forbids assignment of arrays

==> compilation succeeds with warnings on both the array assignment and the variable length array using -Wall -pedantic
gcc -Wall -pedantic -o arrayTest arrayTest.ii
arrayTest.cc: In function `int main()':
arrayTest.cc:19: warning: ISO C++ forbids assignment of arrays
arrayTest.cc:28: warning: ISO C++ forbids assignment of arrays
arrayTest.cc: In function `void printMatrix(int*, int, int)':
arrayTest.cc:38: warning: ISO C++ forbids variable-size array `matrixType'
arrayTest.cc:38: warning: ISO C++ forbids variable-size array `matrixType'

>How-To-Repeat:
Preprocessed source code follows.  Removed cout statements, so print routine is a no-op, but it shows that the compiler handles the non-ISO typedef definition of a variable-length array differently than non-ISO array assignment.

# 1 "arrayTest.cc"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "arrayTest.cc"


void printMatrix(int * matptr, int rows, int cols);

using namespace std;

int main()
{
       int x[3] = {1,2,3};
       int y[3] = {0};

       int x2[3][3] = {{1,2,3},{4,5,6},{7,8,9}};
       int y2[3][3] = {{0}};





       y = x;
# 28 "arrayTest.cc"
       y2 = x2;




       return 0;
}

void printMatrix(int * matptr, int rows, int cols)
{
       typedef int matrixType [rows][cols];
# 62 "arrayTest.cc"
       return;
}
>Fix:
One workaround is to use -pedantic, as illustrated in "Description".
>Release-Note:
>Audit-Trail:
>Unformatted: