ICE: Unwrapping `None` in librustc_typeck/check/method/suggest.rs

[kriw]

Code

use std::io::Write;

struct A<W: std::io::Write> {
    file: Option<lzma::LzmaWriter<W>>,
}

impl<W> A<W> {
    async fn init(&mut self) {
        self.file.unwrap().write("".as_bytes()).unwrap();
    }
}

fn main() {}

Cargo.toml

[dependencies]

rust-lzma = "0.5"

Meta

rustc --version --verbose:

rustc 1.43.0-nightly (2890b37b8 2020-03-06)
binary: rustc
commit-hash: 2890b37b861247de3b8c6ba2ecbcd00048c728a1
commit-date: 2020-03-06
host: x86_64-unknown-linux-gnu
release: 1.43.0-nightly
LLVM version: 9.0

Error output

$ cargo check
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', src/librustc_typeck/check/method/suggest.rs:550:46

Backtrace

stack backtrace:                                        
   0: backtrace::backtrace::libunwind::trace                                                                    
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized                                                                
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/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:1053            
   5: std::io::Write::write_fmt                                                                                 
             at src/libstd/io/mod.rs:1428                                                                       
   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:204                                                                     
   9: std::panicking::default_hook                                                                              
             at src/libstd/panicking.rs:224
  10: rustc_driver::report_ice                                                                                  
  11: std::panicking::rust_panic_with_hook 
             at src/libstd/panicking.rs:474                                                                     
  12: rust_begin_unwind                                                                                         
             at src/libstd/panicking.rs:378                                                                     
  13: core::panicking::panic_fmt                       
             at src/libcore/panicking.rs:85                                                                       14: core::panicking::panic               
             at src/libcore/panicking.rs:52                                                                     
  15: core::ops::function::impls::<impl core::ops::function::FnMut<A> for &mut F>::call_mut                     
  16: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::from_iter
  17: rustc_typeck::check::method::suggest::<impl rustc_typeck::check::FnCtxt>::report_method_error             
  18: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  19: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs      
  20: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  21: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs 
  22: rustc_typeck::check::FnCtxt::check_stmt           
  23: rustc_typeck::check::FnCtxt::check_block_with_expected                                                    
  24: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  25: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs      
  26: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind                     
  27: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  28: rustc_typeck::check::FnCtxt::check_block_with_expected
  29: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  30: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs      
  31: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  32: rustc_typeck::check::check_fn                                                                             
  33: rustc_typeck::check::closure::<impl rustc_typeck::check::FnCtxt>::check_expr_closure
  34: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind                           
  35: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  36: rustc_typeck::check::FnCtxt::check_argument_types
  37: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::confirm_builtin_call
  38: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt>::check_call
  39: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  40: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  41: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  42: rustc_typeck::check::check_fn
  43: rustc::ty::context::GlobalCtxt::enter_local
  44: rustc_typeck::check::typeck_tables_of
  45: rustc::ty::query::__query_compute::typeck_tables_of
  46: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tab
les_of>::compute
  47: rustc::dep_graph::graph::DepGraph::with_task_impl
  48: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  49: rustc_typeck::check::typeck_tables_of
  50: rustc::ty::query::__query_compute::typeck_tables_of
  51: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tab
les_of>::compute
  52: rustc::dep_graph::graph::DepGraph::with_task_impl
  53: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  54: rustc_typeck::collect::type_of::type_of
  55: rustc::ty::query::__query_compute::type_of
  56: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::type_of>::
compute
  57: rustc::dep_graph::graph::DepGraph::with_task_impl
  58: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  59: rustc_hir::intravisit::walk_expr
  60: <rustc_typeck::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_impl_item
  61: rustc::hir::map::Map::visit_item_likes_in_module
  62: rustc_typeck::collect::collect_mod_item_types
  63: rustc::ty::query::__query_compute::collect_mod_item_types
  64: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::collect_mo
d_item_types>::compute
  65: rustc::dep_graph::graph::DepGraph::with_task_impl
  66: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  67: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  68: rustc_typeck::check_crate
  69: rustc_interface::passes::analysis
  70: rustc::ty::query::__query_compute::analysis
  71: rustc::dep_graph::graph::DepGraph::with_task_impl
  72: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  73: rustc::ty::context::tls::enter_global
  74: rustc_interface::interface::run_compiler_in_existing_thread_pool
  75: rustc_ast::attr::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[jonas-schievink]

Might be a duplicate of #69725, please check if it still happens on the current nightly.

[kriw]

It seems the bug is fixed on rustc 1.45.0-nightly, thank you.