/*
REQUIRED_ARGS: -preview=systemVariables
TEST_OUTPUT:
---
fail_compilation/systemvariables_struct.d(31): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(32): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(33): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(36): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(37): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(38): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(54): Error: cannot access `@system` field `S2.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(55): Error: cannot access `@system` field `S2.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(56): Error: cannot access `@system` field `S.syst` in `@safe` code
fail_compilation/systemvariables_struct.d(57): Error: cannot access `@system` field `S.syst` in `@safe` code
---
*/
// http://dlang.org/dips/1035
struct S
{
    @system S* syst;
    @safe S* safe;
}
void aggregate() @safe
{
    S s0;
    // write access
    s0.syst = null;
    __traits(getMember, s0, "syst") = null;
    s0.tupleof[0] = null;
    // read access
    auto a0 = s0.syst;
    auto a1 = __traits(getMember, s0, "syst");
    auto a2 = s0.tupleof[0];
    S s1;
    s1 = s0; // allowed
}
struct S2
{
    @system S syst;
    @safe   S safe;
}
@safe S2 gs2;
void aggregate2() @safe
{
    gs2.syst.syst = null;
    gs2.syst.safe = null;
    gs2.safe.syst = null;
    gs2.safe.syst.safe = null;
    gs2.safe.safe = null; // allowed
}