Closed
Description
When trying to use generic function with capnproto structs the compiler fails to infer types correctly.
I failed to distil the problem to a smaller size.
Capnproto generates code that implements traits like this
impl <'a> ::capnp::traits::Owned<'a> for Owned { type Reader = Reader<'a>; type Builder = Builder<'a>; }
Error
error: internal compiler error: src/librustc/traits/codegen/mod.rs:154: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(TraitPredicate( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>)), depth=2),OutputTypeParameterMismatch(Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle<'_, '_, mozaic::server::runtime::Runtime>, >::Reader)>>), Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>), Sorts(ExpectedFound { expected: mozaic::client_capnp::host_message::Reader<'_>, found: >::Reader }))), FulfillmentError(Obligation(predicate=Binder(TraitPredicate( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>)), depth=2),OutputTypeParameterMismatch(Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle<'_, '_, mozaic::server::runtime::Runtime>, >::Reader)>>), Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::Fn<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>), Sorts(ExpectedFound { expected: mozaic::client_capnp::host_message::Reader<'_>, found: >::Reader }))), FulfillmentError(Obligation(predicate=Binder(TraitPredicate( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>)), depth=2),OutputTypeParameterMismatch(Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle<'_, '_, mozaic::server::runtime::Runtime>, >::Reader)>>), Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>), Sorts(ExpectedFound { expected: mozaic::client_capnp::host_message::Reader<'_>, found: >::Reader }))), FulfillmentError(Obligation(predicate=Binder(TraitPredicate( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>)), depth=2),OutputTypeParameterMismatch(Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle<'_, '_, mozaic::server::runtime::Runtime>, >::Reader)>>), Binder( fn(&'r mut mozaic::messaging::reactor::LinkHandle<'s, 't0, mozaic::server::runtime::Runtime>, >::Reader) -> std::result::Result<(), mozaic::errors::Error> {mozaic::messaging::reactor::e_to_i::} as std::ops::FnOnce<(&mut mozaic::messaging::reactor::LinkHandle, mozaic::client_capnp::host_message::Reader<'_>)>>), Sorts(ExpectedFound { expected: mozaic::client_capnp::host_message::Reader<'_>, found: >::Reader })))]` resolving bounds after type-checking
Which I think can be distilled down to expected: host_message::Reader<'_>, found: <host_message::Owned as Owned<'_>>::Reader
which is the same type.
Meta
rustc --version --verbose
:
rustc 1.37.0 (eae3437df 2019-08-13) binary: rustc commit-hash: eae3437dfe991621e8afdc82734f4a172d7ddf9b commit-date: 2019-08-13 host: x86_64-unknown-linux-gnu release: 1.37.0 LLVM version: 8.0
thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:650:9
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/libunwind.rs:88
1: backtrace::backtrace::trace_unsynchronized
at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:47
3: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:36
4: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:200
5: std::panicking::default_hook
at src/libstd/panicking.rs:214
6: rustc::util::common::panic_hook
7: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:481
8: std::panicking::begin_panic
9: rustc_errors::Handler::bug
10: rustc::util::bug::opt_span_bug_fmt::{{closure}}
11: rustc::ty::context::tls::with_opt::{{closure}}
12: rustc::ty::context::tls::with_context_opt
13: rustc::ty::context::tls::with_opt
14: rustc::util::bug::opt_span_bug_fmt
15: rustc::util::bug::bug_fmt
16: rustc::traits::codegen::<impl rustc::infer::InferCtxt>::drain_fulfillment_cx_or_panic
17: rustc::ty::context::GlobalCtxt::enter_local
18: rustc::traits::codegen::codegen_fulfill_obligation
19: rustc::ty::query::__query_compute::codegen_fulfill_obligation
20: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::codegen_fulfill_obligation>::compute
21: rustc::dep_graph::graph::DepGraph::with_task_impl
22: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
23: rustc::ty::instance::Instance::resolve
24: rustc::ty::instance::Instance::resolve_for_vtable
25: <core::iter::adapters::Cloned<I> as core::iter::traits::iterator::Iterator>::try_fold::{{closure}}
26: <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::try_fold
27: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::spec_extend
28: <rustc_mir::monomorphize::collector::MirNeighborCollector as rustc::mir::visit::Visitor>::visit_rvalue
29: rustc_mir::monomorphize::collector::collect_items_rec
30: rustc_mir::monomorphize::collector::collect_items_rec
31: rustc_mir::monomorphize::collector::collect_items_rec
32: rustc_mir::monomorphize::collector::collect_items_rec
33: rustc_mir::monomorphize::collector::collect_items_rec
34: rustc_mir::monomorphize::collector::collect_items_rec
35: rustc_mir::monomorphize::collector::collect_items_rec
36: rustc_mir::monomorphize::collector::collect_items_rec
37: rustc_mir::monomorphize::collector::collect_items_rec
38: rustc_mir::monomorphize::collector::collect_items_rec
39: rustc_mir::monomorphize::collector::collect_items_rec
40: rustc_mir::monomorphize::collector::collect_items_rec
41: rustc_mir::monomorphize::collector::collect_items_rec
42: rustc_mir::monomorphize::collector::collect_items_rec
43: rustc_mir::monomorphize::collector::collect_items_rec
44: rustc_mir::monomorphize::collector::collect_items_rec
45: rustc_mir::monomorphize::collector::collect_items_rec
46: rustc_mir::monomorphize::collector::collect_crate_mono_items::{{closure}}
47: rustc::util::common::time
48: rustc_mir::monomorphize::collector::collect_crate_mono_items
49: rustc::util::common::time
50: rustc_mir::monomorphize::partitioning::collect_and_partition_mono_items
51: rustc::ty::query::__query_compute::collect_and_partition_mono_items
52: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::collect_and_partition_mono_items>::compute
53: rustc::dep_graph::graph::DepGraph::with_task_impl
54: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
55: rustc_codegen_ssa::base::codegen_crate
56: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
57: rustc::util::common::time
58: rustc_interface::passes::start_codegen
59: rustc::ty::context::tls::enter_global
60: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
61: rustc_interface::passes::create_global_ctxt::{{closure}}
62: rustc_interface::passes::BoxedGlobalCtxt::enter
63: rustc_interface::queries::Query<T>::compute
64: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::ongoing_codegen
65: rustc_interface::interface::run_compiler_in_existing_thread_pool
66: std::thread::local::LocalKey<T>::with
67: scoped_tls::ScopedKey<T>::set
68: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
query stack during panic:
#0 [codegen_fulfill_obligation] checking if `mozaic::messaging::types::Handler` fulfills its obligations
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
My first issue btw, sorry for noobyness.