Parser panic on refactoring use declarations

[zoewithabang]

E.g. running in VSCode, I'm attempting to refactor from

use std::error::Error;
use std::io;

to

use std::{
    error::Error,
    std::io,
};

On adding a curly brace here

use std::{error::Error;
use std::io;

the editor briefly hangs and the following panic is logged several times:

thread '<unnamed>' panicked at 'the parser seems stuck', crates\ra_parser\src\parser.rs:49:9
stack backtrace:
   0: backtrace::backtrace::trace_unsynchronized
             at C:\Users\VssAdministrator\.cargo\registry\src\github.com-1ecc6299db9ec823\backtrace-0.3.35\src\backtrace\mod.rs:66
   1: std::sys_common::backtrace::_print
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libstd\sys_common\backtrace.rs:47
   2: std::sys_common::backtrace::print
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libstd\sys_common\backtrace.rs:36
   3: std::panicking::default_hook::{{closure}}
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libstd\panicking.rs:200
   4: std::panicking::default_hook
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libstd\panicking.rs:214
   5: std::panicking::rust_panic_with_hook
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libstd\panicking.rs:477
   6: std::panicking::begin_panic<str*>
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\src\libstd\panicking.rs:411
   7: ra_parser::parser::Parser::err_recover
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\parser.rs:0
   8: ra_parser::grammar::items::use_item::use_tree
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items\use_item.rs:104
   9: ra_parser::grammar::items::use_item::use_tree_list
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items\use_item.rs:119
  10: ra_parser::grammar::items::use_item::use_tree
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items\use_item.rs:92
  11: ra_parser::grammar::items::use_item::use_item
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items\use_item.rs:6
  12: ra_parser::grammar::items::items_without_modifiers
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items.rs:260
  13: ra_parser::grammar::items::maybe_item
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items.rs:82
  14: ra_parser::grammar::items::item_or_macro
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items.rs:40
  15: ra_parser::grammar::items::mod_contents
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar\items.rs:23
  16: ra_parser::grammar::root
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\grammar.rs:48
  17: core::ops::function::FnOnce::call_once
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\src\libcore\ops\function.rs:227
  18: ra_parser::parse_from_tokens
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\lib.rs:76
  19: ra_parser::parse
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_parser\src\lib.rs:83
  20: ra_syntax::parsing::parse_text
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_syntax\src\parsing.rs:19
  21: ra_syntax::ast::generated::SourceFile::parse
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_syntax\src\lib.rs:149
  22: ra_db::parse_query
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_db\src\lib.rs:103
  23: ra_db::{{impl}}::execute<ra_ide_api::db::RootDatabase>
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_db\src\lib.rs:76
  24: salsa::runtime::Runtime<ra_ide_api::db::RootDatabase>::execute_query_implementation<ra_ide_api::db::RootDatabase,ra_syntax::Parse<ra_syntax::ast::generated::SourceFile>,closure-1>
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\salsa-0.13.0\src\runtime.rs:351
  25: salsa::derived::slot::Slot<ra_ide_api::db::RootDatabase, ra_db::ParseQuery, salsa::derived::AlwaysMemoizeValue>::read_upgrade<ra_ide_api::db::RootDatabase,ra_db::ParseQuery,salsa::derived::AlwaysMemoizeValue>
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\salsa-0.13.0\src\derived\slot.rs:200
  26: salsa::derived::slot::Slot<ra_ide_api::db::RootDatabase, ra_db::ParseQuery, salsa::derived::AlwaysMemoizeValue>::read<ra_ide_api::db::RootDatabase,ra_db::ParseQuery,salsa::derived::AlwaysMemoizeValue>
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\salsa-0.13.0\src\derived\slot.rs:140
  27: salsa::derived::{{impl}}::try_fetch<ra_ide_api::db::RootDatabase,ra_db::ParseQuery,salsa::derived::AlwaysMemoizeValue>
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\salsa-0.13.0\src\derived.rs:140
  28: salsa::QueryTable<ra_ide_api::db::RootDatabase, ra_db::ParseQuery>::get
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\salsa-0.13.0\src\lib.rs:471
  29: ra_db::{{impl}}::parse
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_db\src\lib.rs:70
  30: ra_ide_api::diagnostics::diagnostics
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_ide_api\src\diagnostics.rs:27
  31: ra_ide_api::{{impl}}::diagnostics::{{closure}}
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_ide_api\src\lib.rs:525
  32: ra_db::CheckCanceled::catch_canceled::{{closure}}
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_db\src\lib.rs:39
  33: std::panicking::try::do_call<closure-0,alloc::vec::Vec<ra_ide_api::Diagnostic>>
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\src\libstd\panicking.rs:296
  34: panic_unwind::__rust_maybe_catch_panic
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\/src\libpanic_unwind\lib.rs:80
  35: std::panicking::try
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\src\libstd\panicking.rs:275
  36: std::panic::catch_unwind
             at /rustc/c6e9c76c59e3c10acd63ca9ec157a8894ea1a068\src\libstd\panic.rs:394
  37: ra_db::CheckCanceled::catch_canceled<ra_ide_api::db::RootDatabase,closure-0,alloc::vec::Vec<ra_ide_api::Diagnostic>>
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_db\src\lib.rs:39
  38: ra_ide_api::Analysis::with_db
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_ide_api\src\lib.rs:547
  39: ra_ide_api::Analysis::diagnostics
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_ide_api\src\lib.rs:525
  40: ra_lsp_server::main_loop::handlers::publish_diagnostics
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_lsp_server\src\main_loop\handlers.rs:778
  41: ra_lsp_server::main_loop::update_file_notifications_on_threadpool::{{closure}}
             at C:\Users\user\Documents\Hacks\Rust\rust-analyzer\crates\ra_lsp_server\src\main_loop.rs:680
  42: threadpool::{{impl}}::call_box<closure-0>
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\threadpool-1.7.1\src\lib.rs:95
  43: threadpool::spawn_in_pool::{{closure}}
             at C:\Users\user\.cargo\registry\src\github.com-1ecc6299db9ec823\threadpool-1.7.1\src\lib.rs:767
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.