Custom Box::new throws error

[d-sonuga]

Code

#![no_std]
#![feature(lang_items, start)]

#[lang = "owned_box"]
struct Box<T>(*mut T);

#[lang = "exchange_malloc"]
unsafe fn alloc() -> *mut u8 {
    core::ptr::null_mut()
}

#[lang = "box_free"]
unsafe fn free<T: ?Sized>(ptr: *mut T) { }

impl<T> Box<T> {
    pub fn new(val: T) -> Box<T> {
        Box::new(val)
    }
}

#[start]
fn main(i: isize, args: *const *const u8) -> isize {
    let x = Box::new(3);
    0
}

#[panic_handler]
fn panic_handler(_: &core::panic::PanicInfo) -> ! {
    loop {}
}

Meta

rustc --version --verbose:

rustc 1.63.0-nightly (b31f9cc22 2022-06-15)
binary: rustc
commit-hash: b31f9cc22bcd720b37ddf927afe378108a5b9a54
commit-date: 2022-06-15
host: x86_64-unknown-linux-gnu
release: 1.63.0-nightly
LLVM version: 14.0.5

Error output

thread 'rustc' panicked at 'index out of bounds: the len is 1 but the index is 1', /rustc/b31f9cc22bcd720b37ddf927afe378108a5b9a54/compiler/rustc_middle/src/ty/subst.rs:363:43

Backtrace

stack backtrace:
   0: rust_begin_unwind
             at /rustc/b31f9cc22bcd720b37ddf927afe378108a5b9a54/library/std/src/panicking.rs:584:5
   1: core::panicking::panic_fmt
             at /rustc/b31f9cc22bcd720b37ddf927afe378108a5b9a54/library/core/src/panicking.rs:142:14
   2: core::panicking::panic_bounds_check
             at /rustc/b31f9cc22bcd720b37ddf927afe378108a5b9a54/library/core/src/panicking.rs:84:5
   3: rustc_codegen_llvm::debuginfo::metadata::type_di_node
   4: <rustc_codegen_llvm::context::CodegenCx as rustc_codegen_ssa::traits::debuginfo::DebugInfoMethods>::create_dbg_var
   5: rustc_codegen_ssa::mir::codegen_mir::<rustc_codegen_llvm::builder::Builder>
   6: rustc_codegen_llvm::base::compile_codegen_unit::module_codegen
   7: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, rustc_span::symbol::Symbol, rustc_codegen_ssa::ModuleCodegen<rustc_codegen_llvm::ModuleLlvm>>
   8: rustc_codegen_llvm::base::compile_codegen_unit
   9: <rustc_codegen_llvm::LlvmCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
  10: <rustc_session::session::Session>::time::<alloc::boxed::Box<dyn core::any::Any>, rustc_interface::passes::start_codegen::{closure#0}>
  11: <rustc_interface::passes::QueryContext>::enter::<<rustc_interface::queries::Queries>::ongoing_codegen::{closure#0}::{closure#0}, core::result::Result<alloc::boxed::Box<dyn core::any::Any>, rustc_errors::ErrorGuaranteed>>
  12: <rustc_interface::queries::Queries>::ongoing_codegen
  13: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorGuaranteed>>
  14: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#1}>
  15: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.63.0-nightly (b31f9cc22 2022-06-15) running on x86_64-unknown-linux-gnu

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

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack

[5225225]

I suspect it's failing because Box in the stdlib isn't defined like that, it has an Allocator generic parameter and allocator field.

[PatchMixolydic]

This is probably related to #9307.

[Noratrieb]

The compiler expects lang items and intrinsics to be defined as correctly.