panic: assertion failed: i < this.fields.count() (allocator_api)

[ammkrn]

I recognize this is an unstable feature, but I'm filing this per the compiler's request. I was trying out the allocator_api feature in conjunction with bumpalo ^3.6.1.

Code

#![feature(allocator_api)]
fn main() {
    use bumpalo::Bump;
    let b = Bump::new();
    let x = Box::new_in(1usize, &b);
}

Meta

Not sure if this happens with stable since it's a nightly-only feature.

rustc --version --verbose:

rustc 1.56.0-nightly (574d37568 2021-08-07) running on x86_64-apple-darwin

compiler flags: -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental --crate-type bin

Error output

thread 'rustc' panicked at 'assertion failed: i < this.fields.count()', /rustc/574d37568029f5c637557a87426ade54770d9a14/compiler/rustc_middle/src/ty/layout.rs:2209:21

error: internal compiler error: unexpected panic

Backtrace:

stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: rustc_middle::ty::layout::<impl rustc_target::abi::TyAndLayoutMethods<C> for &rustc_middle::ty::TyS>::field::ty_and_layout_kind
   4: <rustc_target::abi::TyAndLayout<&rustc_middle::ty::TyS> as rustc_codegen_llvm::type_of::LayoutLlvmExt>::scalar_pair_element_llvm_type
   5: <rustc_target::abi::TyAndLayout<&rustc_middle::ty::TyS> as rustc_codegen_llvm::type_of::LayoutLlvmExt>::scalar_pair_element_llvm_type
   6: <rustc_target::abi::call::FnAbi<&rustc_middle::ty::TyS> as rustc_codegen_llvm::abi::FnAbiLlvmExt>::llvm_type
   7: rustc_codegen_llvm::mono_item::<impl rustc_codegen_ssa::traits::declare::PreDefineMethods for rustc_codegen_llvm::context::CodegenCx>::predefine_fn
   8: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen
   9: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task
  10: rustc_codegen_llvm::base::compile_codegen_unit
  11: rustc_codegen_ssa::base::codegen_crate
  12: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  13: rustc_interface::passes::QueryContext::enter
  14: rustc_interface::queries::Queries::ongoing_codegen
  15: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  16: rustc_span::with_source_map
  17: rustc_interface::interface::create_compiler_and_run
  18: scoped_tls::ScopedKey<T>::set

[beepster4096]

I believe this is a duplicate of #78459

[beepster4096]

This needs to be closed. #78459 is closed.