Skip to content

Panic: non-eager expansion without a parent scope #70624

Closed
@zicklag

Description

@zicklag

I tried this code:

macro_rules! breakme {
    ($config:stmt; $($tokens:literal)*) => {
        #[cfg($config)]
        $($tokens)*
    };
}

fn main() {
    macro_rules! unix {
        () => {
            not(unix)
        };
    }

    breakme!(unix!(); "test");
}

I didn't actually expect it to work ( yet ), but it shouldn't have panicked.

Meta

playground link.

Build using the Nightly version: 1.44.0-nightly

(2020-03-30 2113659479a82ea69633)
Backtrace

thread 'rustc' panicked at 'non-eager expansion without a parent scope', src/librustc_resolve/macros.rs:223:37
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1439
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:515
  12: rust_begin_unwind
             at src/libstd/panicking.rs:419
  13: core::panicking::panic_fmt
             at src/libcore/panicking.rs:111
  14: core::option::expect_failed
             at src/libcore/option.rs:1260
  15: rustc_resolve::macros::<impl rustc_expand::base::Resolver for rustc_resolve::Resolver>::resolve_macro_invocation
  16: rustc_expand::expand::MacroExpander::fully_expand_fragment
  17: rustc_expand::expand::MacroExpander::expand_crate
  18: rustc_session::utils::<impl rustc_session::session::Session>::time
  19: rustc_interface::passes::configure_and_expand_inner
  20: rustc_interface::passes::configure_and_expand::{{closure}}
  21: rustc_data_structures::box_region::PinnedGenerator<I,A,R>::new
  22: rustc_interface::passes::configure_and_expand
  23: rustc_interface::queries::Queries::expansion
  24: rustc_interface::interface::run_compiler_in_existing_thread_pool
  25: scoped_tls::ScopedKey<T>::set
  26: rustc_ast::attr::with_globals

Metadata

Metadata

Assignees

No one assigned

    Labels

    A-macrosArea: All kinds of macros (custom derive, macro_rules!, proc macros, ..)C-bugCategory: This is a bug.I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ICEBreaker-Cleanup-CrewHelping to "clean up" bugs with minimal examples and bisectionsP-mediumMedium priorityT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.glacierICE tracked in rust-lang/glacier.

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions