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Code
Sorry, was not able to make it smaller:
trait Document {
type Cursor<'a>: DocCursor<'a>;
fn cursor(&self) -> Self::Cursor<'_>;
}
struct DocumentImpl {}
impl Document for DocumentImpl {
type Cursor<'a> = DocCursorImpl<'a>;
fn cursor(&self) -> Self::Cursor<'_> {
DocCursorImpl {
document: &self,
}
}
}
trait DocCursor<'a> {}
struct DocCursorImpl<'a> {
document: &'a DocumentImpl,
}
impl<'a> DocCursor<'a> for DocCursorImpl<'a> {}
struct Lexer<'d, Cursor>
where
Cursor: DocCursor<'d>,
{
cursor: Cursor,
_phantom: std::marker::PhantomData<&'d ()>,
}
impl<'d, Cursor> Lexer<'d, Cursor>
where
Cursor: DocCursor<'d>,
{
pub fn from<Doc>(document: &'d Doc) -> Lexer<'d, Cursor>
where
Doc: Document<Cursor = Cursor>,
{
Lexer {
cursor: document.cursor(),
_phantom: std::marker::PhantomData,
}
}
}
pub fn test() {
let doc = DocumentImpl {};
let lexer: Lexer<'_, DocCursorImpl<'_>> = Lexer::from(&doc);
}
Meta
rustc --version --verbose
:
rustc 1.44.0-nightly (f509b26a7 2020-03-18)
binary: rustc
commit-hash: f509b26a7730d721ef87423a72b3fdf8724b4afa
commit-date: 2020-03-18
host: x86_64-unknown-linux-gnu
release: 1.44.0-nightly
LLVM version: 9.0
Error output
error: internal compiler error: src/librustc_codegen_llvm/context.rs:855:
failed to get layout for `expl::Lexer<[type error]>`: the type `[type error]` has an unknown layout
thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:880:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
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 1.44.0-nightly (f509b26a7 2020-03-18) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: aborting due to previous error
Backtrace
thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:880:9
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:1069
5: std::io::Write::write_fmt
at src/libstd/io/mod.rs:1427
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:198
9: std::panicking::default_hook
at src/libstd/panicking.rs:218
10: rustc_driver::report_ice
11: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:515
12: std::panicking::begin_panic
13: rustc_errors::HandlerInner::bug
14: rustc_errors::Handler::bug
15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
16: rustc::ty::context::tls::with_opt::{{closure}}
17: rustc::ty::context::tls::with_opt
18: rustc::util::bug::opt_span_bug_fmt
19: rustc::util::bug::bug_fmt
20: <rustc_codegen_llvm::context::CodegenCx as rustc_target::abi::LayoutOf>::spanned_layout_of::{{closure}}
21: <rustc_codegen_llvm::context::CodegenCx as rustc_target::abi::LayoutOf>::layout_of
22: <rustc_target::abi::call::FnAbi<&rustc::ty::TyS> as rustc::ty::layout::FnAbiExt<C>>::of_instance
23: rustc_codegen_ssa::mir::block::<impl rustc_codegen_ssa::mir::FunctionCx<Bx>>::codegen_call_terminator
24: rustc_codegen_ssa::mir::block::<impl rustc_codegen_ssa::mir::FunctionCx<Bx>>::codegen_block
25: rustc_codegen_ssa::base::codegen_instance
26: <rustc::mir::mono::MonoItem as rustc_codegen_ssa::mono_item::MonoItemExt>::define
27: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen
28: rustc::dep_graph::graph::DepGraph::with_task
29: rustc_codegen_llvm::base::compile_codegen_unit
30: rustc_codegen_ssa::base::codegen_crate
31: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_utils::codegen_backend::CodegenBackend>::codegen_crate
32: rustc_session::utils::<impl rustc_session::session::Session>::time
33: rustc_interface::passes::start_codegen
34: rustc::ty::context::tls::enter_global
35: rustc_interface::queries::Queries::ongoing_codegen
36: rustc_interface::interface::run_compiler_in_existing_thread_pool
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
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Area: Generic associated types (GATs)Category: This is a bug.Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue.Call for participation: An issue has been fixed and does not reproduce, but no test has been added.`#![feature(generic_associated_types)]` a.k.a. GATsIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️Relevant to the compiler team, which will review and decide on the PR/issue.ICE tracked in rust-lang/glacier.This issue requires a nightly compiler in some way.