ICE on roman numeral macro example

[ghost]

Description of Problem

I'm trying to run the roman numeral compiler plugin code in the documentation (here). The compiler panics with this error:

thread 'rustc' panicked at 'cannot access a scoped thread local variable without calling `set` first', /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:168:9

Code to Reproduce

My code is in this repo: github.com/mgoelzer/rust-macros-roman

Expected vs Actual Behavior

I run cargo build from the root of that repo. I expect the code to compile without errors.

Instead, the compiler panics like this:

$ cargo build
   Compiling roman-test v0.1.0 (/Users/mwg/code/rust-macros-roman-numerals/roman-test)
thread 'rustc' panicked at 'cannot access a scoped thread local variable without calling `set` first', /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:168:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.

error: internal compiler error: unexpected panic

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

note: rustc 1.38.0-nightly (b0e40bfba 2019-08-02) running on x86_64-apple-darwin

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `roman-test`.

To learn more, run the command again with --verbose.

Meta

$ rustc --version --verbose
rustc 1.38.0-nightly (b0e40bfba 2019-08-02)
binary: rustc
commit-hash: b0e40bfba44836ad30051ffb077c1cfc5bf4a59f
commit-date: 2019-08-02
host: x86_64-apple-darwin
release: 1.38.0-nightly
LLVM version: 9.0

$ cargo --version --verbose
cargo 1.38.0-nightly (26092da33 2019-07-31)
release: 1.38.0
commit-hash: 26092da337b948719549cd5ed3d1051fd847afd7
commit-date: 2019-07-31

Backtrace

$ RUST_BACKTRACE=1 cargo build
   Compiling roman-test v0.1.0 (/Users/mwg/code/rust-macros-roman-numerals/roman-test)
thread 'rustc' panicked at 'cannot access a scoped thread local variable without calling `set` first', /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:168:9
stack backtrace:
   0: <unknown>
   1: <unknown>
   2: <unknown>
   3: <unknown>
   4: std::panicking::begin_panic
   5: scoped_tls::ScopedKey<T>::with
   6: core::ptr::real_drop_in_place
   7: <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop
   8: __rustc_plugin_registrar_7649699624c1ca169dcc2215a85ad889__
             at roman/src/lib.rs:60
   9: <unknown>
  10: <unknown>
  11: <unknown>
  12: <unknown>
  13: <unknown>
  14: <unknown>
  15: <unknown>
  16: <unknown>
  17: <unknown>
  18: <unknown>
  19: <unknown>
  20: <unknown>
  21: <unknown>
  22: <unknown>
  23: <unknown>
query stack during panic:
end of query stack

error: internal compiler error: unexpected panic

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

note: rustc 1.38.0-nightly (b0e40bfba 2019-08-02) running on x86_64-apple-darwin

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

error: Could not compile `roman-test`.

To learn more, run the command again with --verbose.

Related Issues

Searching in Google, another issue with the same error is #53469

#27271 is another user trying to compile the roman numeral example, but his problem is different.

[petrochenkov]

Duplicate of #62717.

The problem can be solved by linking to rustc_driver (extern crate rustc_driver;) from the crate that defines the plugin.
#62727 is currently trying to make sure that rustc_driver is always linked.

Note that #[plugin] in general is deprecated, and the preferred way to solve problems like implementing roman numerals is using stable proc_macro interface.