Encountered errors [...] resolving bounds after type-checking [rustc 1.28.0-nightly (952f344cd 2018-05-18)]

[foxfriends]

When using shred-derive to #[derive(SystemData)], I am encountering this error:

error: internal compiler error: librustc/traits/codegen/mod.rs:169: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate(<Thing as std::default::Default>)),depth=2),Unimplemented)]` resolving bounds after type-checking

Implementing Default for Thing does allow the program to compile.

I tried this code:

src/lib.rs:

extern crate specs;
extern crate shred;
#[macro_use] extern crate shred_derive;

use specs::prelude::*;

struct Thing;

#[derive(SystemData)]
struct Container<'a> {
    current_scene: Write<'a, Thing>,
}

Cargo.toml:

[package]
name = "test"
version = "0.1.0"

[lib]
name = "test"
path = "src/lib.rs"

[dependencies]
specs = "0.11"
shred = "0.7"
shred-derive = "0.5"
specs-derive = "0.2"

I expected to see this happen: Compile (or at least a compile error)

Instead, this happened: Compiler panicked!

Meta

rustc 1.28.0-nightly (952f344cd 2018-05-18)
binary: rustc
commit-hash: 952f344cdc0bca58d9f6c54dcfbae0890246e886
commit-date: 2018-05-18
host: x86_64-unknown-linux-gnu
release: 1.28.0-nightly
LLVM version: 6.0

Backtrace:

thread 'main' panicked at 'Box<Any>', librustc_errors/lib.rs:499:9
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:71
             at libstd/sys_common/backtrace.rs:59
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:211
   3: std::panicking::default_hook
             at libstd/panicking.rs:227
   4: rustc::util::common::panic_hook
   5: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:467
   6: std::panicking::begin_panic
   7: rustc_errors::Handler::span_bug
   8: rustc::session::opt_span_bug_fmt::{{closure}}
   9: rustc::ty::context::tls::with_opt::{{closure}}
  10: rustc::ty::context::tls::with_context_opt
  11: rustc::ty::context::tls::with_opt
  12: rustc::session::opt_span_bug_fmt
  13: rustc::session::span_bug_fmt
  14: rustc::traits::codegen::<impl rustc::infer::InferCtxt<'a, 'gcx, 'tcx>>::drain_fulfillment_cx_or_panic
  15: rustc::ty::context::tls::with_related_context
  16: rustc::traits::codegen::codegen_fulfill_obligation
  17: rustc::ty::maps::<impl rustc::ty::maps::config::QueryConfig<'tcx> for rustc::ty::maps::queries::codegen_fulfill_obligation<'tcx>>::compute
  18: rustc::ty::context::tls::with_context
  19: rustc::dep_graph::graph::DepGraph::with_task_impl
  20: rustc::ty::context::tls::with_related_context
  21: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
  22: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  23: rustc::ty::instance::Instance::resolve
  24: <rustc_mir::monomorphize::collector::MirNeighborCollector<'a, 'tcx> as rustc::mir::visit::Visitor<'tcx>>::visit_terminator_kind
  25: rustc_mir::monomorphize::collector::collect_items_rec
  26: rustc_mir::monomorphize::collector::collect_crate_mono_items
  27: rustc::util::common::time
  28: rustc_codegen_llvm::base::collect_and_partition_mono_items
  29: rustc::ty::context::tls::with_context
  30: rustc::dep_graph::graph::DepGraph::with_task_impl
  31: rustc::ty::context::tls::with_related_context
  32: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
  33: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  34: rustc_codegen_llvm::back::symbol_export::exported_symbols_provider_local
  35: rustc::ty::context::tls::with_context
  36: rustc::dep_graph::graph::DepGraph::with_task_impl
  37: rustc::ty::context::tls::with_related_context
  38: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::force_query_with_job
  39: rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  40: rustc_metadata::encoder::encode_metadata
  41: rustc_metadata::cstore_impl::<impl rustc::middle::cstore::CrateStore for rustc_metadata::cstore::CStore>::encode_metadata
  42: rustc::ty::context::TyCtxt::encode_metadata
  43: rustc_codegen_llvm::base::write_metadata
  44: rustc::util::common::time
  45: rustc_codegen_llvm::base::codegen_crate
  46: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
  47: rustc::util::common::time
  48: rustc_driver::driver::phase_4_codegen
  49: rustc_driver::driver::compile_input::{{closure}}
  50: rustc::ty::context::tls::enter_context
  51: <std::thread::local::LocalKey<T>>::with
  52: rustc::ty::context::TyCtxt::create_and_enter
  53: rustc_driver::driver::compile_input
  54: rustc_driver::run_compiler_with_pool
  55: syntax::with_globals
  56: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
  57: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:105
  58: rustc_driver::run
  59: rustc_driver::main
  60: std::rt::lang_start::{{closure}}
  61: std::panicking::try::do_call
             at libstd/rt.rs:59
             at libstd/panicking.rs:310
  62: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:105
  63: std::rt::lang_start_internal
             at libstd/panicking.rs:289
             at libstd/panic.rs:374
             at libstd/rt.rs:58
  64: main
  65: __libc_start_main
  66: <unknown>
query stack during panic:
#0 [codegen_fulfill_obligation] checking if `specs::SystemData` fulfills its obligations
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
#2 [exported_symbols] exported_symbols
end of query stack

[jakubadamw]

This can be closed as the original code builds fine both under 1.36.0 and nightly-2019-08-07.

[Noratrieb]

There is neither a reproduction nor an MCVE, so this is not really actionable. Closing as unactionable, feel free to reopen if you encounter new issues.