#zig build-obj {
--name test -fno-emit-bin
-Mroot=test.zig
#}

#write test.zig {
const FooType = opaque {};
export fn bar() FooType {
    return error.InvalidValue;
}
#}
#update
#check errors {
test.zig:2:17: error: opaque return type 'test.FooType' not allowed
test.zig:1:17: note: opaque declared here
#}
