ICE when using nested macro calls: 'no entry found for key'

[lorepozo]

This issue probably needs a better title, perhaps someone more familiar with the compiler's handling of macros can suggest a better one.

Code

playground

macro_rules! make_foodoc {
    ($outer:ident, $inner:ident) => {
        concat!("outer: ", stringify!($outer), " ; inner: ", stringify!($inner))
    }
}

macro_rules! make_foo {
    ($doc:expr, $outer:ident, $inner:ident) => {
        #[doc = $doc ]
        #[derive(Debug)]
        pub struct $outer($inner);
    }
}

make_foo!(make_foodoc!(MyFoo, i32), MyFoo, i32);

fn main() {
    let f = MyFoo(0);
    println!("{:?}", f);
}

Version

# rustc --version --verbose
rustc 1.20.0 (f3d6973f4 2017-08-27)
binary: rustc
commit-hash: f3d6973f41a7d1fb83029c9c0ceaf0f5d4fd7208
commit-date: 2017-08-27
host: x86_64-apple-darwin
release: 1.20.0
LLVM version: 4.0

Expected Behavior

Some kind of error message, at least.

Actual Behavior

panic with exit code 101:

$ RUST_BACKTRACE=full rustc main.rs
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 1.20.0 (f3d6973f4 2017-08-27) running on x86_64-apple-darwin

note: run with `RUST_BACKTRACE=1` for a backtrace

thread 'rustc' panicked at 'no entry found for key', src/libcore/option.rs:819:4
stack backtrace:
   0:        0x10c7de6c3 - std::sys::imp::backtrace::tracing::imp::unwind_backtrace::h5d6b821bcccc8af3
   1:        0x10c7eb73a - std::panicking::default_hook::{{closure}}::haca53f8b96e15b81
   2:        0x10c7eb238 - std::panicking::default_hook::h0029f59c1ec97ffc
   3:        0x10c7eda02 - std::panicking::rust_panic_with_hook::hb8eae939c3fcaf9c
   4:        0x10c7ed864 - std::panicking::begin_panic_new::h3c5f9a0be81106be
   5:        0x10c7ed7b2 - std::panicking::begin_panic_fmt::hf585b6224c51a06c
   6:        0x10c7ed71a - rust_begin_unwind
   7:        0x10c82eb73 - core::panicking::panic_fmt::h13ed235e8f32b1d5
   8:        0x10c82ebdd - core::option::expect_failed::hcda4f7b77532dbdc
   9:        0x1077ca622 - rustc_resolve::macros::<impl rustc_resolve::Resolver<'a>>::resolve_macro_to_def::hfdf39b9e743bd0a1
  10:        0x1077c945d - rustc_resolve::macros::<impl syntax::ext::base::Resolver for rustc_resolve::Resolver<'a>>::resolve_invoc::h6533cd14622b0f6e
  11:        0x10c1461a0 - syntax::ext::expand::MacroExpander::expand::h14f5532b993820a5
  12:        0x10c145182 - syntax::ext::expand::MacroExpander::expand_crate::h0ee7fed5f1132fa4
  13:        0x1075f13cc - rustc_driver::driver::phase_2_configure_and_expand::{{closure}}::h87fe884b6ee57e81
  14:        0x1075eb807 - rustc_driver::driver::phase_2_configure_and_expand::h8b4927fdd561d907
  15:        0x1075e4c83 - rustc_driver::driver::compile_input::hed13f3a0f9e4f9ca
  16:        0x1076246b0 - rustc_driver::run_compiler::h08be8ddbdb667b6f
  17:        0x107551e30 - std::sys_common::backtrace::__rust_begin_short_backtrace::h2887c3163846925d
  18:        0x10c81da4c - __rust_maybe_catch_panic
  19:        0x10758596f - <F as alloc::boxed::FnBox<A>>::call_box::h4c5af747e717c038
  20:        0x10c7ea71b - std::sys::imp::thread::Thread::new::thread_start::h823686b907c11c46
  21:     0x7fff4f0b56c0 - _pthread_body
  22:     0x7fff4f0b556c - _pthread_start

[kennytm]

Simplified:

macro_rules! a {
    () => { "a" }
}

macro_rules! b {
    ($doc:expr) => {
        #[doc = $doc]
        pub struct B;
    }
}

b!(a!());

Same ICE will happen if expr is changed to stmt/pat/item/block.

---

Update: Panic happens at this line:

rust/src/librustc_resolve/macros.rs

Line 404 in 1c4510a

let invocation = self.invocations[&scope];

self.invocations has keys Mark(0) and Mark(1), but the scope is Mark(2).