panic

goal.c

struct extra_data {
    int foo,
    int bar,
};

struct data_type {
    const char *str;
    struct extra_data *data;
};

static struct extra_data extra = { .foo = 0, .bar = 1 };

static const struct data_type data = { 
    .str = "Hello, world",
    .data = &extra
};

__attribute__((section("some_section")))
static const struct data_type *data_ptr = &data;

int main(void) { return 0; }

panic.rs

struct ExtraData {
    foo: i32,
    bar: i32,
}

struct DataType {
    str: *const u8,
    data: *mut ExtraData,
}

unsafe impl Sync for ExtraData { }
unsafe impl Sync for DataType { }

static mut EXTRA_DATA : ExtraData = ExtraData {
        foo: 0,
        bar: 1,
    };

static DATA : DataType = DataType {
        str: b"hello world\0" as *const u8,
        data: unsafe { &mut EXTRA_DATA }
    };

#[link_section="some_section"]
static DATA_PTR : *const DataType = &DATA;

fn main() {
}

rustc.log

$ RUST_BACKTRACE=1 rustc panic.rs
panic.rs:1:1: 4:2 warning: struct is never used: `ExtraData`, #[warn(dead_code)] on by default
panic.rs:1 struct ExtraData {
panic.rs:2     foo: i32,
panic.rs:3     bar: i32,
panic.rs:4 }
panic.rs:2:5: 2:13 warning: struct field is never used: `foo`, #[warn(dead_code)] on by default
panic.rs:2     foo: i32,
               ^~~~~~~~
panic.rs:3:5: 3:13 warning: struct field is never used: `bar`, #[warn(dead_code)] on by default
panic.rs:3     bar: i32,
               ^~~~~~~~
panic.rs:6:1: 9:2 warning: struct is never used: `DataType`, #[warn(dead_code)] on by default
panic.rs:6 struct DataType {
panic.rs:7     str: *const u8,
panic.rs:8     data: *mut ExtraData,
panic.rs:9 }
panic.rs:7:5: 7:19 warning: struct field is never used: `str`, #[warn(dead_code)] on by default
panic.rs:7     str: *const u8,
               ^~~~~~~~~~~~~~
panic.rs:8:5: 8:25 warning: struct field is never used: `data`, #[warn(dead_code)] on by default
panic.rs:8     data: *mut ExtraData,
               ^~~~~~~~~~~~~~~~~~~~
panic.rs:14:1: 17:7 warning: static item is never used: `EXTRA_DATA`, #[warn(dead_code)] on by default
panic.rs:14 static mut EXTRA_DATA : ExtraData = ExtraData {
panic.rs:15         foo: 0,
panic.rs:16         bar: 1,
panic.rs:17     };
panic.rs:19:1: 22:7 warning: static item is never used: `DATA`, #[warn(dead_code)] on by default
panic.rs:19 static DATA : DataType = DataType {
panic.rs:20         str: b"hello world\0" as *const u8,
panic.rs:21         data: unsafe { &mut EXTRA_DATA }
panic.rs:22     };
panic.rs:25:1: 25:43 warning: static item is never used: `DATA_PTR`, #[warn(dead_code)] on by default
panic.rs:25 static DATA_PTR : *const DataType = &DATA;
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
panic.rs:21:29: 21:39 error: internal compiler error: expected a const, fn, struct, or variant def
panic.rs:21         data: unsafe { &mut EXTRA_DATA }
                                        ^~~~~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
thread 'rustc' panicked at 'Box<Any>', src/libsyntax/diagnostic.rs:176

stack backtrace:
   1:     0x7f6706dcf66e - sys::backtrace::write::ha67a6a2049d22fadIvs
   2:     0x7f6706dd7d55 - panicking::on_panic::hfa4bf0215983f759lzx
   3:     0x7f6706d9894e - rt::unwind::begin_unwind_inner::ha1b5da93bdf7e8ffC0w
   4:     0x7f67041becdc - rt::unwind::begin_unwind::h10002216390169315342
   5:     0x7f67041bec7b - diagnostic::SpanHandler::span_bug::h6d3d1eb598e37d9aX6A
   6:     0x7f6704c8dcf8 - session::Session::span_bug::h103bc02ef373c2e4nRt
   7:     0x7f6705c357ad - trans::consts::const_expr_unadjusted::h1d2d83c04c480e728Et
   8:     0x7f6705c32e7f - trans::consts::const_expr::h08aedd7988733ed6Yot
   9:     0x7f6705c35a1c - trans::consts::const_expr_unadjusted::h1d2d83c04c480e728Et
  10:     0x7f6705c32e7f - trans::consts::const_expr::h08aedd7988733ed6Yot
  11:     0x7f6705c34fce - trans::consts::const_expr_unadjusted::h1d2d83c04c480e728Et
  12:     0x7f6705c32e7f - trans::consts::const_expr::h08aedd7988733ed6Yot
  13:     0x7f6705c3e727 - trans::consts::const_expr_unadjusted::closure.49914
  14:     0x7f6705c3e593 - vec::Vec<T>.FromIterator<T>::from_iter::h17887475302167253138
  15:     0x7f6705c3e089 - trans::consts::const_expr_unadjusted::closure.49903
  16:     0x7f6705c36212 - trans::consts::const_expr_unadjusted::h1d2d83c04c480e728Et
  17:     0x7f6705c32e7f - trans::consts::const_expr::h08aedd7988733ed6Yot
  18:     0x7f6705bdc493 - trans::base::trans_item::hd3ac3af06c93993fPdj
  19:     0x7f6705be940c - trans::base::trans_crate::h14e6ea6d455593f8i0j
  20:     0x7f670733e2f4 - driver::phase_4_translate_to_llvm::h8ce7c7bfb0fd9b185Oa
  21:     0x7f6707338885 - driver::phase_3_run_analysis_passes::closure.16542
  22:     0x7f6707332ab1 - middle::ty::ctxt<'tcx>::create_and_enter::h9578579149294230291
  23:     0x7f670732d991 - driver::phase_3_run_analysis_passes::h8415522514568150077
  24:     0x7f6707311a90 - driver::compile_input::h52c7dafd49963360Tba
  25:     0x7f67073f7a63 - run_compiler::h473c62e00f865fa9A7b
  26:     0x7f67073f54de - boxed::F.FnBox<A>::call_box::h10713159552398332324
  27:     0x7f67073f4e09 - rt::unwind::try::try_fn::h16887904248528792425
  28:     0x7f6706dd784d - __rust_try
  29:     0x7f6706dc28f7 - rt::unwind::try::inner_try::hafffff77ddacfa5fvWw
  30:     0x7f67073f5028 - boxed::F.FnBox<A>::call_box::h5417278073590676257
  31:     0x7f6706dd6991 - sys::thread::Thread::new::thread_start::h29dca2a2cf2294b535v
  32:     0x7f6701678353 - start_thread
  33:     0x7f6706a34bfc - __clone
  34:                0x0 - <unknown>