[Bug][Compiler] compiling overflows stack

[igor-aptos]

🐛 Bug

Adding:

    public fun borrow<K, V>(self: &OrderedMao<K, V>, key: &K): &V {
        self.find(key).iter_borrow(self)
    }

function to the WIP implementation of OrderedMap, makes the compiler (I think) overflow its stack.

Commenting out borrow/borrow_mut in aptos-move/framework/aptos-stdlib/sources/data_structures/ordered_map.move doesn't trigger stack overflow.

To reproduce

check out igor/ordered_map branch, and run:

cargo run -p aptos --release -- move test --move-2 --filter ordered_map --package-dir aptos-move/framework/aptos-stdlib

And you'll get:

INCLUDING DEPENDENCY MoveStdlib
BUILDING AptosStdlib

thread 'main' has overflowed its stack
fatal runtime error: stack overflow

Adding RUST_MIN_STACK=104857600 to the command, doesn't resolve it.

Code snippet to reproduce

module aptos_std::ordered_map {
    use std::vector;
    use std::option::{Self, Option};
    use std::error;

    // Trying to do an operation on an Iterator that would go out of bounds
    const EITER_OUT_OF_BOUNDS: u64 = 3;

    /// Individual entry holding (key, value) pair
    struct Entry<K, V> has drop, copy, store {
        key: K,
        value: V,
    }

    /// The OrderedMap datastructure.
    enum OrderedMap<K, V> has drop, copy, store {
        /// sorted-vector based implementation of OrderedMap
        SortedVectorMap {
            /// List of entries, sorted by key.
            entries: vector<Entry<K, V>>,
        }
    }

    /// An iterator pointing to a position between two elements in the
    enum Iterator has copy, drop {
        // TODO: see if it is cleaner/faster to have end-iter be Position { index = len() }
        // and not have a separate variant for it.
        End,
        Position {
            /// The index of the iterator pointing to.
            index: u64,
        },
    }

    /// Returns an iterator pointing to the element that equals to the provided key, or an end
    /// iterator if the key is not found.
    public fun find<K, V>(self: &OrderedMap<K, V>, key: &K): Iterator {
        Iterator::End
    }

    /// Borrows the value given iterator points to.
    /// Note: Requires that the map is not changed after the input iterator is generated.
    public fun iter_borrow<K, V>(self: Iterator, map: &OrderedMap<K, V>): &V {
        assert!(!(self is Iterator::End), error::invalid_argument(EITER_OUT_OF_BOUNDS));
        &map.entries.borrow(self.index).value
    }

    public fun borrow<K, V>(self: &OrderedMao<K, V>, key: &K): &V {
        self.find(key).iter_borrow(self)
    }

    public native fun compare<T>(first: &T, second: &T): Ordering;
}

Stack trace/error message

// Paste the output here

Expected Behavior

A clear and concise description of what you expected to happen.

System information

Please complete the following information:

• Aptos Core Version
• Rust Version
• Computer OS

Additional context

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[brmataptos]

I managed to reproduce this in lldb-rust. Here is the stack trace, which suggests that this is in some code I recently modified:

... continue repeating above here...
    frame #18913: �[33m0x0000000100e4fddc�[0m build-script-build`core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$mut$u20$F$GT$::call_once::h89cad98ea9975088(self=0x000000016fdde498, args=(&&(move_model::model::Loc, move_model::ty::WideningOrder, move_model::ty::Constraint)) @ 0x000000016fdddbf0) at �[36mfunction.rs�[0m:�[33m305�[0m:�[33m13�[0m
    frame #18914: �[33m0x0000000100fd3f2c�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562 [inlined] core::option::Option$LT$T$GT$::map::h57bb33e84c8a257d at �[36moption.rs�[0m:�[33m1073�[0m:�[33m29�[0m
    frame #18915: �[33m0x0000000100fd3f28�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562(self=0x000000016fdde488) at �[36mmap.rs�[0m:�[33m108�[0m:�[33m26�[0m
    frame #18916: �[33m0x000000010100f67c�[0m build-script-build`itertools::Itertools::join::hee4abf2e04250930(self=0x000000016fdde488, sep=" + ") at �[36mlib.rs�[0m:�[33m2300�[0m:�[33m15�[0m
    frame #18917: �[33m0x0000000100e872f0�[0m build-script-build`_$LT$move_model..ty..TypeDisplay$u20$as$u20$core..fmt..Display$GT$::fmt::hf004df8883b03586(self=0x000000016fdde8c0, f=0x000000016fdde710) at �[36mty.rs�[0m:�[33m3404�[0m:�[33m35�[0m
    frame #18918: �[33m0x00000001023019c8�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 [inlined] core::fmt::rt::Argument::fmt::h5ddc0f22b2928899 at �[36mrt.rs�[0m:�[33m142�[0m:�[33m9�[0m [opt]
    frame #18919: �[33m0x00000001023019bc�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 at �[36mmod.rs�[0m:�[33m1153�[0m:�[33m17�[0m [opt]
    frame #18920: �[33m0x000000010216ec24�[0m build-script-build`_$LT$$RF$mut$u20$W$u20$as$u20$core..fmt..Write..write_fmt..SpecWriteFmt$GT$::spec_write_fmt::h6b83a459e529679d(self=0x000000016fdde8e8, args=Arguments @ 0x000000016fdde900) at �[36mmod.rs�[0m:�[33m218�[0m:�[33m21�[0m
    frame #18921: �[33m0x000000010216c8d0�[0m build-script-build`core::fmt::Write::write_fmt::h883aa85270746f47(self=0x000000016fdde8e8, args=<unavailable>) at �[36mmod.rs�[0m:�[33m223�[0m:�[33m9�[0m
    frame #18922: �[33m0x000000010100dae0�[0m build-script-build`itertools::Itertools::join::h6fcc67e8fcb7b007(self=0x000000016fdde9d8, sep=",") at �[36mlib.rs�[0m:�[33m2306�[0m:�[33m17�[0m
    frame #18923: �[33m0x0000000100e78184�[0m build-script-build`move_model::ty::Constraint::display::fmt_types::hd52e008eb3ba9a80(ctx=0x000000016fde1680, tys=Iter<move_model::ty::Type> @ 0x000000016fddea00) at �[36mty.rs�[0m:�[33m588�[0m:�[33m13�[0m
    frame #18924: �[33m0x0000000100e77f88�[0m build-script-build`move_model::ty::Constraint::display::h97c22c5091cba69a(self=0x000000014c308320, display_context=0x000000016fde1680) at �[36mty.rs�[0m:�[33m630�[0m:�[33m21�[0m
    frame #18925: �[33m0x0000000100e87690�[0m build-script-build`_$LT$move_model..ty..TypeDisplay$u20$as$u20$core..fmt..Display$GT$::fmt::_$u7b$$u7b$closure$u7d$$u7d$::hc8cc3573e380b208((null)=0x0000600003074520) at �[36mty.rs�[0m:�[33m3406�[0m:�[33m46�[0m
    frame #18926: �[33m0x0000000100e4fddc�[0m build-script-build`core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$mut$u20$F$GT$::call_once::h89cad98ea9975088(self=0x000000016fddfaa8, args=(&&(move_model::model::Loc, move_model::ty::WideningOrder, move_model::ty::Constraint)) @ 0x000000016fddf200) at �[36mfunction.rs�[0m:�[33m305�[0m:�[33m13�[0m
    frame #18927: �[33m0x0000000100fd3f2c�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562 [inlined] core::option::Option$LT$T$GT$::map::h57bb33e84c8a257d at �[36moption.rs�[0m:�[33m1073�[0m:�[33m29�[0m
    frame #18928: �[33m0x0000000100fd3f28�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562(self=0x000000016fddfa98) at �[36mmap.rs�[0m:�[33m108�[0m:�[33m26�[0m
    frame #18929: �[33m0x000000010100f67c�[0m build-script-build`itertools::Itertools::join::hee4abf2e04250930(self=0x000000016fddfa98, sep=" + ") at �[36mlib.rs�[0m:�[33m2300�[0m:�[33m15�[0m
    frame #18930: �[33m0x0000000100e872f0�[0m build-script-build`_$LT$move_model..ty..TypeDisplay$u20$as$u20$core..fmt..Display$GT$::fmt::hf004df8883b03586(self=0x000000016fddfed0, f=0x000000016fddfd20) at �[36mty.rs�[0m:�[33m3404�[0m:�[33m35�[0m
    frame #18931: �[33m0x00000001023019c8�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 [inlined] core::fmt::rt::Argument::fmt::h5ddc0f22b2928899 at �[36mrt.rs�[0m:�[33m142�[0m:�[33m9�[0m [opt]
    frame #18932: �[33m0x00000001023019bc�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 at �[36mmod.rs�[0m:�[33m1153�[0m:�[33m17�[0m [opt]
    frame #18933: �[33m0x000000010216ec24�[0m build-script-build`_$LT$$RF$mut$u20$W$u20$as$u20$core..fmt..Write..write_fmt..SpecWriteFmt$GT$::spec_write_fmt::h6b83a459e529679d(self=0x000000016fddfef8, args=Arguments @ 0x000000016fddff10) at �[36mmod.rs�[0m:�[33m218�[0m:�[33m21�[0m
    frame #18934: �[33m0x000000010216c8d0�[0m build-script-build`core::fmt::Write::write_fmt::h883aa85270746f47(self=0x000000016fddfef8, args=<unavailable>) at �[36mmod.rs�[0m:�[33m223�[0m:�[33m9�[0m
    frame #18935: �[33m0x000000010100dae0�[0m build-script-build`itertools::Itertools::join::h6fcc67e8fcb7b007(self=0x000000016fddffe8, sep=",") at �[36mlib.rs�[0m:�[33m2306�[0m:�[33m17�[0m
    frame #18936: �[33m0x0000000100e78184�[0m build-script-build`move_model::ty::Constraint::display::fmt_types::hd52e008eb3ba9a80(ctx=0x000000016fde1680, tys=Iter<move_model::ty::Type> @ 0x000000016fde0010) at �[36mty.rs�[0m:�[33m588�[0m:�[33m13�[0m
    frame #18937: �[33m0x0000000100e77f88�[0m build-script-build`move_model::ty::Constraint::display::h97c22c5091cba69a(self=0x000000014c308320, display_context=0x000000016fde1680) at �[36mty.rs�[0m:�[33m630�[0m:�[33m21�[0m
    frame #18938: �[33m0x0000000100e87690�[0m build-script-build`_$LT$move_model..ty..TypeDisplay$u20$as$u20$core..fmt..Display$GT$::fmt::_$u7b$$u7b$closure$u7d$$u7d$::hc8cc3573e380b208((null)=0x0000600003074c00) at �[36mty.rs�[0m:�[33m3406�[0m:�[33m46�[0m
    frame #18939: �[33m0x0000000100e4fddc�[0m build-script-build`core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$mut$u20$F$GT$::call_once::h89cad98ea9975088(self=0x000000016fde10b8, args=(&&(move_model::model::Loc, move_model::ty::WideningOrder, move_model::ty::Constraint)) @ 0x000000016fde0810) at �[36mfunction.rs�[0m:�[33m305�[0m:�[33m13�[0m
    frame #18940: �[33m0x0000000100fd3f2c�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562 [inlined] core::option::Option$LT$T$GT$::map::h57bb33e84c8a257d at �[36moption.rs�[0m:�[33m1073�[0m:�[33m29�[0m
    frame #18941: �[33m0x0000000100fd3f28�[0m build-script-build`_$LT$core..iter..adapters..map..Map$LT$I$C$F$GT$$u20$as$u20$core..iter..traits..iterator..Iterator$GT$::next::h187e51fe1bae4562(self=0x000000016fde10a8) at �[36mmap.rs�[0m:�[33m108�[0m:�[33m26�[0m
    frame #18942: �[33m0x000000010100f67c�[0m build-script-build`itertools::Itertools::join::hee4abf2e04250930(self=0x000000016fde10a8, sep=" + ") at �[36mlib.rs�[0m:�[33m2300�[0m:�[33m15�[0m
    frame #18943: �[33m0x0000000100e872f0�[0m build-script-build`_$LT$move_model..ty..TypeDisplay$u20$as$u20$core..fmt..Display$GT$::fmt::hf004df8883b03586(self=0x000000016fde1670, f=0x000000016fde1330) at �[36mty.rs�[0m:�[33m3404�[0m:�[33m35�[0m
    frame #18944: �[33m0x00000001023019c8�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 [inlined] core::fmt::rt::Argument::fmt::h5ddc0f22b2928899 at �[36mrt.rs�[0m:�[33m142�[0m:�[33m9�[0m [opt]
    frame #18945: �[33m0x00000001023019bc�[0m build-script-build`core::fmt::write::hbadb443a71b75f23 at �[36mmod.rs�[0m:�[33m1153�[0m:�[33m17�[0m [opt]
    frame #18946: �[33m0x00000001022f9b44�[0m build-script-build`alloc::fmt::format::format_inner::hb2f7e8bea7badd53 [inlined] _$LT$$RF$mut$u20$W$u20$as$u20$core..fmt..Write..write_fmt..SpecWriteFmt$GT$::spec_write_fmt::h4ab8cf5f445901c4 at �[36mmod.rs�[0m:�[33m218�[0m:�[33m21�[0m [opt]
    frame #18947: �[33m0x00000001022f9b30�[0m build-script-build`alloc::fmt::format::format_inner::hb2f7e8bea7badd53 [inlined] core::fmt::Write::write_fmt::h33100cdeee1fd32e at �[36mmod.rs�[0m:�[33m223�[0m:�[33m9�[0m [opt]
    frame #18948: �[33m0x00000001022f9b30�[0m build-script-build`alloc::fmt::format::format_inner::hb2f7e8bea7badd53 at �[36mfmt.rs�[0m:�[33m633�[0m:�[33m16�[0m [opt]
    frame #18949: �[33m0x00000001020bcb48�[0m build-script-build`alloc::fmt::format::_$u7b$$u7b$closure$u7d$$u7d$::hbcb3cb7f30bbd70a at �[36mfmt.rs�[0m:�[33m637�[0m:�[33m34�[0m
    frame #18950: �[33m0x00000001020b5b1c�[0m build-script-build`core::option::Option$LT$T$GT$::map_or_else::h0941f991c39bf72d(self=Option<&str> @ 0x000000016fde1488, default={closure_env#0} @ 0x000000016fde14b0, f=0x00000102ffa9c800) at �[36moption.rs�[0m:�[33m1179�[0m:�[33m21�[0m
    frame #18951: �[33m0x0000000100e48334�[0m build-script-build`alloc::fmt::format::hf974edaaa92a6a51(args=Arguments @ 0x000000016fde1630) at �[36mfmt.rs�[0m:�[33m637�[0m:�[33m5�[0m
    frame #18952: �[33m0x0000000100ea436c�[0m build-script-build`move_model::builder::exp_builder::ExpTranslator::finalize_type::h74da270a9ddb88cc(self=0x000000016fde1b60, node_id=NodeId @ 0x000000016fde16f8, ty=0x000000016fde1878, reported_vars=0x000000016fde1800) at �[36mexp_builder.rs�[0m:�[33m422�[0m:�[33m18�[0m
    frame #18953: �[33m0x0000000100ea3fa4�[0m build-script-build`move_model::builder::exp_builder::ExpTranslator::finalize_types::h7727fcb2b00d4053(self=0x000000016fde1b60) at �[36mexp_builder.rs�[0m:�[33m383�[0m:�[33m30�[0m
    frame #18954: �[33m0x0000000100e61190�[0m build-script-build`move_model::builder::module_builder::ModuleBuilder::def_ana_fun::hfbafdc95cd2557db(self=0x000000016fde3338, name=0x000000016fde25d8, def=0x000000014d09f328) at �[36mmodule_builder.rs�[0m:�[33m1504�[0m:�[33m13�[0m
    frame #18955: �[33m0x0000000100e5e264�[0m build-script-build`move_model::builder::module_builder::ModuleBuilder::def_ana::hc3ebdbb701619781(self=0x000000016fde3338, module_def=0x000000016fde3618, compiled_module=0x000000016fde3730) at �[36mmodule_builder.rs�[0m:�[33m1057�[0m:�[33m13�[0m
    frame #18956: �[33m0x0000000100e587a4�[0m build-script-build`move_model::builder::module_builder::ModuleBuilder::translate::hc769e3f5d2de6bd4(self=0x000000016fde3338, loc=Loc @ 0x000000016fde3600, module_def=ModuleDefinition @ 0x000000016fde3618, compiled_module=Option<move_model::builder::module_builder::BytecodeModule> @ 0x000000016fde3730) at �[36mmodule_builder.rs�[0m:�[33m199�[0m:�[33m9�[0m
    frame #18957: �[33m0x0000000100ede360�[0m build-script-build`move_model::run_move_checker::h41701539b582feba(env=0x000000016fde53f8, program=Program @ 0x000000016fde95e0) at �[36mlib.rs�[0m:�[33m433�[0m:�[33m9�[0m
    frame #18958: �[33m0x0000000100edc3ac�[0m build-script-build`move_model::run_model_builder_with_options_and_compilation_flags::h50688f7a4910ab2f(move_sources_targets=size=1, move_sources_deps=size=1, deps=size=1, options=ModelBuilderOptions @ 0x000000016fde53f0, flags=Flags @ 0x000000016fde9d30, known_attributes=0x000000016fdebde8) at �[36mlib.rs�[0m:�[33m406�[0m:�[33m9�[0m
    frame #18959: �[33m0x0000000100edb1a0�[0m build-script-build`move_model::run_model_builder_in_compiler_mode::h601705a800b9d714(source=PackageInfo @ 0x000000016fdea9e0, source_deps=PackageInfo @ 0x000000016fdeaa40, deps=size=1, skip_attribute_checks=false, known_attributes=0x000000016fdebde8, language_version=V2_0, warn_of_deprecation_use=false, warn_of_deprecation_use_in_aptos_libs=false, compile_test_code=false, compile_verify_code=false) at �[36mlib.rs�[0m:�[33m106�[0m:�[33m5�[0m
    frame #18960: �[33m0x00000001009bca20�[0m build-script-build`move_compiler_v2::run_checker::h1f9e040f12755472(options=Options @ 0x000000016fdebd58) at �[36mlib.rs�[0m:�[33m178�[0m:�[33m19�[0m
    frame #18961: �[33m0x00000001009bcde4�[0m build-script-build`move_compiler_v2::run_checker_and_rewriters::h1107a1d6bc9a74de(options=Options @ 0x000000016fded020) at �[36mlib.rs�[0m:�[33m225�[0m:�[33m19�[0m
    frame #18962: �[33m0x00000001009bb808�[0m build-script-build`move_compiler_v2::run_move_compiler::hbac97fa9db1f5782(error_writer=0x000000016fdede18, options=Options @ 0x000000016fdee818) at �[36mlib.rs�[0m:�[33m96�[0m:�[33m19�[0m
    frame #18963: �[33m0x00000001001e46d8�[0m build-script-build`move_package::compilation::compiled_package::build_and_report_no_exit_v2_driver::h8750c6b68fe2e4f7(options=Options @ 0x000000016fdef698) at �[36mcompiled_package.rs�[0m:�[33m1134�[0m:�[33m24�[0m
    frame #18964: �[33m0x0000000100031978�[0m build-script-build`core::ops::function::FnMut::call_mut::h2b9b313a371f07dd + 52
    frame #18965: �[33m0x000000010002eda0�[0m build-script-build`move_package::compilation::compiled_package::CompiledPackage::build_all::h6101a9665efc50da + 5416
    frame #18966: �[33m0x000000010001c410�[0m build-script-build`move_package::compilation::build_plan::BuildPlan::compile_with_driver::ha9ad1f61cd64c62e + 540
    frame #18967: �[33m0x000000010001bcb0�[0m build-script-build`move_package::compilation::build_plan::BuildPlan::compile_no_exit::h1d0caf5a8a76d1ad + 28
    frame #18968: �[33m0x0000000100020968�[0m build-script-build`move_package::BuildConfig::compile_package_no_exit::hd7ef56ed237b7f9e + 592
    frame #18969: �[33m0x000000010004d3f4�[0m build-script-build`aptos_framework::built_package::BuiltPackage::build::h44b2421a23a7171d + 1020
    frame #18970: �[33m0x000000010002c4c4�[0m build-script-build`aptos_framework::release_builder::ReleaseOptions::create_release::h58b966a2617199df + 1616
    frame #18971: �[33m0x000000010002be64�[0m build-script-build`aptos_framework::aptos::ReleaseTarget::create_release::h1b76fda30b0c3518 + 36
    frame #18972: �[33m0x0000000100005010�[0m build-script-build`build_script_build::main::h9125cf48ef013eab + 5068
    frame #18973: �[33m0x00000001000038e8�[0m build-script-build`core::ops::function::FnOnce::call_once::h69cced58f78ef7e3 + 16
    frame #18974: �[33m0x00000001000036cc�[0m build-script-build`std::sys_common::backtrace::__rust_begin_short_backtrace::h49845b1881852f19 + 12
    frame #18975: �[33m0x0000000100003738�[0m build-script-build`std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::hb99f79cbdf1c637e + 20
    frame #18976: �[33m0x00000001022d5754�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$F$GT$::call_once::heaba8a29e0324069 at �[36mfunction.rs�[0m:�[33m284�[0m:�[33m13�[0m [opt]
    frame #18977: �[33m0x00000001022d574c�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panicking::try::do_call::h6e5fac4f4884d97b at �[36mpanicking.rs�[0m:�[33m552�[0m:�[33m40�[0m [opt]
    frame #18978: �[33m0x00000001022d574c�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panicking::try::h2b98e2f3cf76cd78 at �[36mpanicking.rs�[0m:�[33m516�[0m:�[33m19�[0m [opt]
    frame #18979: �[33m0x00000001022d574c�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panic::catch_unwind::hba9c97319335c08b at �[36mpanic.rs�[0m:�[33m146�[0m:�[33m14�[0m [opt]
    frame #18980: �[33m0x00000001022d574c�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::rt::lang_start_internal::_$u7b$$u7b$closure$u7d$$u7d$::h18efdcfb68f002e8 at �[36mrt.rs�[0m:�[33m148�[0m:�[33m48�[0m [opt]
    frame #18981: �[33m0x00000001022d574c�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panicking::try::do_call::ha793e16770aada4d at �[36mpanicking.rs�[0m:�[33m552�[0m:�[33m40�[0m [opt]
    frame #18982: �[33m0x00000001022d5748�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panicking::try::h8aa812e3e1310d12 at �[36mpanicking.rs�[0m:�[33m516�[0m:�[33m19�[0m [opt]
    frame #18983: �[33m0x00000001022d5748�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 [inlined] std::panic::catch_unwind::h38c4879f2623185e at �[36mpanic.rs�[0m:�[33m146�[0m:�[33m14�[0m [opt]
    frame #18984: �[33m0x00000001022d5748�[0m build-script-build`std::rt::lang_start_internal::h39923ab4c3913741 at �[36mrt.rs�[0m:�[33m148�[0m:�[33m20�[0m [opt]
    frame #18985: �[33m0x0000000100003710�[0m build-script-build`std::rt::lang_start::h3e11e950ce4f896a + 60
    frame #18986: �[33m0x00000001000050f4�[0m build-script-build`main + 36
    frame #18987: �[33m0x0000000193f620e0�[0m dyld`start + 2360

[brmataptos]

Summarizing the stack above:

...
ty.rs:588:13
ty.rs:630:21
ty.rs:3406:46
ty.rs:3404:35
ty.rs:588:13
ty.rs:630:21
ty.rs:3406:46
ty.rs:3404:35
exp_builder.rs:422:18

[brmataptos]

It looks like there is a type variable which doesn't have a type yet but is constrained by Constraint::SomeReceiverFunction whose display includes the type variable itself.

[brmataptos]

exp_builder is trying to print an error,

• https://github.com/aptos-labs/aptos-core/blob/igor/ordered_map/third_party/move/move-model/src/builder/exp_builder.rs#422
  so it calls TypeDisplayContext.display on the type, which find a variable type, which has a substitution, so it calls TypeDisplayContext.display on the substitution:
• https://github.com/aptos-labs/aptos-core/blob/igor/ordered_map/third_party/move/move-model/src/ty.rs#L3404
  which turns out to also be a variable type, which has no substitution, but has a constraint, so that is displayed:
• https://github.com/aptos-labs/aptos-core/blob/igor/ordered_map/third_party/move/move-model/src/ty.rs#L3406
  The constraint is a SomeReceiverFunction constraint, which is displayed as "fun self.{}{}({}):{}" including the list of parameter types to the receiver function.
• https://github.com/aptos-labs/aptos-core/blob/igor/ordered_map/third_party/move/move-model/src/ty.rs#L630
  The first parameter type to the function is the original type
• https://github.com/aptos-labs/aptos-core/blob/igor/ordered_map/third_party/move/move-model/src/ty.rs#L588
  which we try to display, leading to a cycle.