Compiler error for extern "C" struct

[Martinsos]

simple.cpp:
#include "simple_ispc.h"
extern "C" struct Test {
int b;
};
int main() {
ispc::simple();
}

simple.ispc:
extern "C" struct Test;
export void simple() {
Test t;
}

compile command:
ispc simple.ispc -o simple_ispc.o -h simple_ispc.h

Error message:
func.cpp(423): FATAL ERROR: Function verificication failed

---

*** Please file a bug report at https://github.com/ispc/ispc/issues
*** (Including as much information as you can about how to reproduce this error).
*** You have apparently encountered a bug in the compiler that we'd like to fix!

---

main.cpp(204): FATAL ERROR: Unhandled signal sent to process; terminating.

ispc version: 1.3.0
machine: Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz

[dbabokin]

Here's the stack:
#0 0x00000037eac35935 in raise () from /lib64/libc.so.6
#1 0x00000037eac370e8 in abort () from /lib64/libc.so.6
#2 0x000000000058a1f2 in FatalError (file=0x1762b0b "func.cpp", line=439, message=0x1762dd0 "Function verificication failed") at util.cpp:451
#3 0x0000000000529252 in Function::GenerateIR (this=0x3100110) at func.cpp:439
#4 0x00000000004a35d7 in AST::GenerateIR (this=0x271a230) at ast.cpp:68
#5 0x000000000053913f in Module::CompileFile (this=0x271a6f0) at module.cpp:361
#6 0x00000000005403ce in Module::CompileAndOutput (srcFile=0x7fffffffd898 "simple.ispc", arch=0x0, cpu=0x0, target=0x0, generatePIC=false, outputType=Module::Object, outFileName=0x7fffffffd8a7 "simple_ispc.o",
headerFileName=0x7fffffffd8b8 "simple_ispc.h", includeFileName=0x0, depsFileName=0x0, hostStubFileName=0x0, devStubFileName=0x0) at module.cpp:2281
#7 0x0000000000537d9d in main (Argc=6, Argv=0x7fffffffd548) at main.cpp:50

If function verification (func.cpp:436) is called with llvm::PrintMessageAction, it reports the following:
Cannot allocate unsized type
%t = alloca %v8_varying_Test

Which makes perfect sense, as "Test" is not fully defined type. I.e. to make it work, you need to have in ispc file:
extern "C" struct Test {
int b;
};

This would be good to catch during LLVM IR generation and issue a nice error message.