passing a generator as tmp into a macro caused an ICE: ```Rust #![feature(generators, generator_trait)] use std::ops::{GeneratorState, Generator}; macro_rules! yield_from { ($generator:expr) => { unsafe { loop { match $generator.resume() { GeneratorState::Yielded(y) => yield y, GeneratorState::Complete(ret) => break ret, } } } }; } fn main() { || { yield_from!(|| { yield; }); return; }; } ``` Backtrace: ``` error: internal compiler error: librustc_mir\transform\generator.rs:495: Broken MIR: generator contains type [generator@src\lib.rs:108:25: 110:14 {()}] in MIR, but typeck only knows about for<'r> {&'r mut [generator@src\lib.rs:108:25: 110:14 {()}], std::ops::GeneratorState<(), ()>, ()} --> src\lib.rs:107:9 | 107 | / || { 108 | | yield_from!(|| { 109 | | yield; 110 | | }); 111 | | return; 112 | | }; | |_________^ thread 'main' panicked at 'Box<Any>', librustc_errors\lib.rs:499:9 stack backtrace: 0: <std::collections::hash::map::DefaultHasher as core::fmt::Debug>::fmt 1: <std::sys::windows::dynamic_lib::DynamicLibrary as core::ops::drop::Drop>::drop 2: std::panicking::take_hook 3: std::panicking::take_hook 4: <rustc::ty::SymbolName as core::fmt::Debug>::fmt 5: std::panicking::rust_panic_with_hook 6: <rustc_mir::dataflow::graphviz::Edge as core::fmt::Debug>::fmt 7: <rustc_mir::transform::uniform_array_move_out::LocalUse as core::fmt::Debug>::fmt 8: <rustc_mir::transform::qualify_consts::Qualif as core::fmt::UpperHex>::fmt 9: <rustc_mir::transform::qualify_consts::Qualif as core::fmt::UpperHex>::fmt 10: <rustc_mir::transform::qualify_consts::Qualif as core::fmt::UpperHex>::fmt 11: <rustc_mir::transform::qualify_consts::Qualif as core::fmt::UpperHex>::fmt 12: <rustc_mir::dataflow::impls::borrows::Borrows<'a, 'gcx, 'tcx> as rustc_mir::dataflow::BitDenotation>::start_block_effect 13: <rustc_mir::dataflow::impls::borrows::Borrows<'a, 'gcx, 'tcx> as rustc_mir::dataflow::BitDenotation>::start_block_effect 14: <rustc_mir::transform::generator::StateTransform as rustc_mir::transform::MirPass>::run_pass 15: <rustc_mir::transform::MirSource as core::fmt::Debug>::fmt 16: rustc_mir::transform::optimized_mir 17: rustc::ty::query::on_disk_cache::__ty_decoder_impl::<impl serialize::serialize::Decoder for rustc::ty::query::on_disk_cache::CacheDecoder<'a, 'tcx, 'x>>::read_str 18: rustc::ty::context::tls::track_diagnostic 19: rustc::ty::context::tls::track_diagnostic 20: rustc::dep_graph::graph::DepGraph::assert_ignored 21: rustc::ty::context::tls::track_diagnostic 22: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 23: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 24: rustc::ty::query::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::optimized_mir 25: rustc_mir::shim::provide 26: rustc::ty::query::on_disk_cache::__ty_decoder_impl::<impl serialize::serialize::Decoder for rustc::ty::query::on_disk_cache::CacheDecoder<'a, 'tcx, 'x>>::read_str 27: rustc::ty::context::tls::track_diagnostic 28: rustc::ty::context::tls::track_diagnostic 29: rustc::dep_graph::graph::DepGraph::assert_ignored 30: rustc::ty::context::tls::track_diagnostic 31: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 32: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 33: rustc::ty::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::instance_mir 34: rustc_mir::monomorphize::collector::collect_crate_mono_items 35: rustc_mir::monomorphize::collector::collect_crate_mono_items 36: rustc_mir::util::def_use::Info::use_count 37: <rustc_mir::dataflow::impls::borrows::Borrows<'a, 'gcx, 'tcx> as rustc_mir::dataflow::BitDenotation>::start_block_effect 38: rustc_mir::monomorphize::collector::collect_crate_mono_items 39: <rustc_codegen_llvm::time_graph::TimelineId as core::fmt::Debug>::fmt 40: <rustc_codegen_llvm::base::ValueIter as core::iter::iterator::Iterator>::next 41: rustc::ty::context::tls::track_diagnostic 42: rustc::ty::context::tls::track_diagnostic 43: rustc::dep_graph::graph::DepGraph::assert_ignored 44: rustc::ty::context::tls::track_diagnostic 45: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 47: <rustc_codegen_llvm::back::linker::MsvcLinker<'a> as rustc_codegen_llvm::back::linker::Linker>::finalize 48: rustc::ty::context::tls::track_diagnostic 49: rustc::ty::context::tls::track_diagnostic 50: rustc::dep_graph::graph::DepGraph::assert_ignored 51: rustc::ty::context::tls::track_diagnostic 52: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 53: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::try_print_query_stack 54: <rustc_metadata::encoder::ImplVisitor<'a, 'tcx> as rustc::hir::itemlikevisit::ItemLikeVisitor<'v>>::visit_item 55: rustc_metadata::cstore_impl::<impl rustc::middle::cstore::CrateStore for rustc_metadata::cstore::CStore>::encode_metadata 56: rustc::ty::context::TyCtxt::encode_metadata 57: rustc_codegen_llvm::base::codegen_instance 58: <rustc_codegen_llvm::time_graph::TimelineId as core::fmt::Debug>::fmt 59: <rustc_codegen_llvm::base::ValueIter as core::iter::iterator::Iterator>::next 60: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate 61: rustc_driver::target_features::add_configuration 62: rustc_driver::driver::phase_4_codegen 63: rustc_driver::profile::dump 64: <humantime::date::Error as std::error::Error>::cause 65: <rustc_driver::pretty::IdentifiedAnnotation<'hir> as rustc_driver::pretty::PrinterSupport>::sess 66: <unknown> 67: rustc_driver::driver::compile_input 68: rustc_driver::run_compiler 69: <env_logger::filter::inner::Filter as core::fmt::Display>::fmt 70: <rustc_driver::derive_registrar::Finder as rustc::hir::itemlikevisit::ItemLikeVisitor<'v>>::visit_item 71: _rust_maybe_catch_panic 72: <rustc_driver::derive_registrar::Finder as rustc::hir::itemlikevisit::ItemLikeVisitor<'v>>::visit_item 73: rustc_driver::main 74: <unknown> 75: std::panicking::update_panic_count 76: _rust_maybe_catch_panic 77: std::rt::lang_start_internal 78: <unknown> 79: <unknown> 80: BaseThreadInitThunk 81: RtlUserThreadStart query stack during panic: #0 [optimized_mir] processing `internal_compiler_errors::broken_mir::{{closure}}` #1 [mir_shims] generating MIR shim for `std::ptr::drop_in_place` #2 [collect_and_partition_mono_items] collect_and_partition_mono_items #3 [exported_symbols] exported_symbols end of query stack error: aborting due to previous error 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 1.28.0-nightly (e3bf634e0 2018-06-28) running on x86_64-pc-windows-msvc note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib note: some of the compiler flags provided by cargo are hidden ```
