unexpected panic with command line option --extern

[michelou]

Goal : Build imagetool example using only rustc.exe without Cargo.toml (we specify the external dependency image as rustc option).

Here is the compiler output :

> "%USERPROFILE%\.cargo\bin\rustc.exe" --version
rustc 1.66.1 (90743e729 2023-01-10)

> "%USERPROFILE%\.cargo\bin\rustc.exe" -g  --crate-name "imagetool" --crate-type bin --edition 2021 --out-dir "R:\mastering-rust\Chapter02\imgtool\target" --target "x86_64-pc-windows-msvc" -L crate --extern "image=%USERPROFILE%\.cargo\registry\cache\github.com-1ecc6299db9ec823\image-0.24.5.crate"  "R:\mastering-rust\Chapter02\imgtool\src\main.rs"
thread 'rustc' panicked at 'identifier: "metadata_crate_location_unknown_type", attr: None, args: FluentArgs([("path", String("%USERPROFILE%\\.cargo\\registry\\cache\\github.com-1ecc6299db9ec823\\image-0.24.5.crate"))]), errors: [ResolverError(Reference(Variable { id: "crate_name" }))]', compiler\rustc_errors\src\translation.rs:105:17
stack backtrace:
   0:     0x7ff935df9a62 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc97dbc4fe64c9e1d
   1:     0x7ff935e356db - core::fmt::write::ha369a394538739aa
   2:     0x7ff935dec18a - <std::io::IoSlice as core::fmt::Debug>::fmt::h479b71bd3dadc1d1
   3:     0x7ff935df97ab - std::sys::common::alloc::realloc_fallback::h233ebec439b629e2
   4:     0x7ff935dfd109 - std::panicking::default_hook::h0ab9e14ad869b271
   5:     0x7ff935dfcd8a - std::panicking::default_hook::h0ab9e14ad869b271
   6:     0x7ff8cb0c1d6e - rustc_driver[e9de03b45d14c171]::describe_lints
   7:     0x7ff935dfda60 - std::panicking::rust_panic_with_hook::he7a40468954ae645
   8:     0x7ff935dfd7bd - <std::panicking::begin_panic_handler::StrPanicPayload as core::panic::BoxMeUp>::get::h44bc3105923add49
   9:     0x7ff935dfa76f - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc97dbc4fe64c9e1d
  10:     0x7ff935dfd480 - rust_begin_unwind
  11:     0x7ff935e6b5f5 - core::panicking::panic_fmt::h1862038ee9bad685
  12:     0x7ff8c97b9f06 - rustc_errors[20be445f3eba0fb3]::emitter::is_case_difference
  13:     0x7ff8c97b1284 - <rustc_errors[20be445f3eba0fb3]::emitter::EmitterWriter>::ui_testing
  14:     0x7ff8c97abbdc - <rustc_errors[20be445f3eba0fb3]::emitter::EmitterWriter as rustc_errors[20be445f3eba0fb3]::emitter::Emitter>::emit_diagnostic
  15:     0x7ff8c97a4271 - <rustc_errors[20be445f3eba0fb3]::HandlerInner>::emit_diagnostic
  16:     0x7ff8c97a36d2 - <rustc_errors[20be445f3eba0fb3]::Handler>::emit_diagnostic
  17:     0x7ff8cd4935eb - <rustc_errors[20be445f3eba0fb3]::ErrorGuaranteed as rustc_errors[20be445f3eba0fb3]::diagnostic_builder::EmissionGuarantee>::diagnostic_builder_emit_producing_guarantee
  18:     0x7ff8ccf9e10a - <rustc_metadata[dac8933e4ad73025]::errors::CannotFindCrate as rustc_errors[20be445f3eba0fb3]::diagnostic_builder::IntoDiagnostic>::into_diagnostic
  19:     0x7ff8ccfb7e0b - <rustc_metadata[dac8933e4ad73025]::locator::MetadataError as core[a1be09f172195029]::fmt::Display>::fmt
  20:     0x7ff8c954c1af - <rustc_metadata[dac8933e4ad73025]::creader::CrateLoader>::into_cstore
  21:     0x7ff8c954e1c5 - <rustc_metadata[dac8933e4ad73025]::creader::CrateLoader>::process_path_extern
  22:     0x7ff8ca5c669e - <rustc_resolve[7c01eaad461df3a4]::Resolver>::expect_module
  23:     0x7ff8ca62397c - <<rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor>::find_lifetime_for_self::SelfVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  24:     0x7ff8ca62acae - <<rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor>::find_lifetime_for_self::SelfVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  25:     0x7ff8ca628a7e - <<rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor>::find_lifetime_for_self::SelfVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  26:     0x7ff8ca628b5d - <<rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor>::find_lifetime_for_self::SelfVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  27:     0x7ff8ca5f9264 - <rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_local
  28:     0x7ff8ca5f8a1a - <rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_block
  29:     0x7ff8ca601970 - <rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_fn
  30:     0x7ff8ca651cf6 - <rustc_resolve[7c01eaad461df3a4]::build_reduced_graph::BuildReducedGraphVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  31:     0x7ff8ca611446 - <<rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor>::find_lifetime_for_self::SelfVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  32:     0x7ff8ca5f83dc - <rustc_resolve[7c01eaad461df3a4]::late::LateResolutionVisitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_item
  33:     0x7ff8c919f092 - <rustc_builtin_macros[cca7005986e3d0e7]::deriving::generic::find_type_parameters::Visitor as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_ty
  34:     0x7ff8c91b2447 - <rustc_resolve[7c01eaad461df3a4]::def_collector::DefCollector as rustc_ast[6de64748d468de7f]::visit::Visitor>::visit_param
  35:     0x7ff8c91a81d1 - <rustc_resolve[7c01eaad461df3a4]::Resolver>::resolve_crate
  36:     0x7ff8c8917b22 - <rustc_interface[10a7111f9310fd6d]::passes::LintStoreExpandImpl as rustc_expand[c56eb5aee4619b21]::base::LintStoreExpand>::pre_expansion_lint
  37:     0x7ff8c890940e - <rustc_interface[10a7111f9310fd6d]::queries::Queries>::expansion
  38:     0x7ff8c88dc477 - <rustc_middle[18c13081b174ae21]::ty::SymbolName as core[a1be09f172195029]::fmt::Display>::fmt
  39:     0x7ff8c88db6dd - rustc_driver[e9de03b45d14c171]::args::arg_expand_all
  40:     0x7ff8c88cc809 - <unknown>
  41:     0x7ff8c88c3990 - <unknown>
  42:     0x7ff935e0eabc - std::sys::windows::thread::Thread::new::haf1327b4da6a4ac1
  43:     0x7ff9988026bd - BaseThreadInitThunk
  44:     0x7ff9991adfb8 - RtlUserThreadStart

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 1.66.1 (90743e729 2023-01-10) running on x86_64-pc-windows-msvc

note: compiler flags: --crate-type bin

query stack during panic:
end of query stack

PS. Rust source file src\main.rs is :

use std::env;
use std::path::Path;
use std::process;

fn main() {
    let arg = env::args().skip(1).next();
    if arg.is_none() {
        println!("Error: Missing argument specifying the image file");
        process::exit(1);
    }
    let image_path = arg.unwrap();
    let path = Path::new(&image_path);
    let img = image::open(path).unwrap();
    let rotated = img.rotate90();
    
    // do not modify the input file
    let out_path = Path::new("target").join(path.file_name().unwrap());
    rotated.save(out_path).unwrap();
}

[est31]

You are passing a .crate file to rustc, this won't work. .crate files are cargo-specific tar.gz archives of source code, while rust expects, for dependencies, pre-compiled binary libraries. You need to extract the image crate, compile it, then pass that to the example. In general, given that image has a non trivial dependencies of its own, this is a quite tedious task to do manually so you'd likely need some kind of automation.

There still seems to be a valid bug, where if you pass an invalid file as dependency, rustc is ICE'ing, which it shouldn't. Instead it should print an error.

[fmease]

This should be fixed in 1.67 (current beta) by #104621.

[michelou]

@est31, @fmease 👍

[michelou]

Looks good with 1.67 :

> "%USERPROFILE%\.cargo\bin\rustc.exe" -g  --crate-name "imagetool" --crate-type bin --edition 2021 --out-dir "R:\mastering-rust\Chapter02\imgtool\target" --target "x86_64-pc-windows-msvc" -L crate --extern "image=%USERPROFILE%\.cargo\registry\cache\github.com-1ecc6299db9ec823\image-0.24.5.crate"  "R:\mastering-rust\Chapter02\imgtool\src\main.rs"
error: extern location for image is of an unknown type: %USERPROFILE%\.cargo\registry\cache\github.com-1ecc6299db9ec823\image-0.24.5.crate

[fmease]

Great! So this can be closed then

[michelou]

rustc is no more ICE'ing.