by giacomo.tartari:

What steps will reproduce the problem?

1.
//put this code in $GOPATH/src/mytest/mytest.go
package mytest

/*
typedef struct{
        int x;
        int data[0];
} cStruct;

*/
import "C"

type GoStruct struct {
        C.cStruct
}

2.
cd $GOPATH/src/mytest
go build

What is the expected output?


What do you see instead?
# mytest
struct size calculation error

Which compiler are you using (5g, 6g, 8g, gccgo)?
$6g -V
6g version weekly.2012-01-27 11520

Which operating system are you using?
OS X Lion 10.7.2 

Which revision are you using?  (hg identify)
$ hg identify
23995c78329e tip

Please provide any additional information below.

It compiles on Snow leopard or using the "old" gcc installed via macports.

Here is with the default gcc:

$ gcc
i686-apple-darwin11-llvm-gcc-4.2: no input files
$ gcc -v
Using built-in specs.
Target: i686-apple-darwin11
Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.1~22/src/configure
--disable-checking --enable-werror --prefix=/Developer/usr/llvm-gcc-4.2
--mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-prefix=llvm-
--program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib
--build=i686-apple-darwin11
--enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.1~22/dst-llvmCore/Developer/usr/local
--program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11
--target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)
$ go build
# mytest
struct size calculation error

And here with the "old" gcc

$export $GCC=/opt/local/bin/gcc-apple-4.2
$ $GCC
i686-apple-darwin11-gcc-apple-4.2.1: no input files
$ $GCC -v
Using built-in specs.
Target: i686-apple-darwin11
Configured with:
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_lang_apple-gcc42/apple-gcc42/work/objroot/src/configure
--disable-checking --prefix=/opt/local --mandir=/opt/local/share/man
--enable-languages=c,c++,objc,obj-c++ --libexecdir=/opt/local/libexec/apple-gcc42
--libdir=/opt/local/lib/apple-gcc42 --includedir=/opt/local/include/apple-gcc42
--program-suffix=-apple-4.2 --with-system-zlib --disable-nls --with-gmp=/opt/local
--with-mpfr=/opt/local --with-slibdir=/usr/lib --build=x86_64-apple-darwin11
--enable-werror-always --program-prefix=i686-apple-darwin11-
--host=x86_64-apple-darwin11 --target=i686-apple-darwin11
--with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Apple Inc. build 5666) (dot 3)
$ go build
$