language server crashed about slint

[hunger]

We will take a while to get into this issue as everybody is at the embedded world conference this week. Sorry.

[hunger]

I can reproduce this: The LSP seems fine though, the Live preview crashes (but since both are in the same binary, the difference is of course not really user-visible;-).

Here is the backtrace I get when I click on Show Preview on AppWindow:

thread 'main' panicked at internal/interpreter/eval.rs:1397:71:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0: rust_begin_unwind
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/panicking.rs:646:5
   1: core::panicking::panic_fmt
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/panicking.rs:72:14
   2: core::panicking::panic
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/panicking.rs:141:5
   3: core::option::unwrap_failed
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/option.rs:1984:5
   4: core::option::Option<T>::unwrap
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/option.rs:932:21
   5: slint_interpreter::eval::enclosing_component_for_element
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:1397:31
   6: slint_interpreter::eval::enclosing_component_instance_for_element
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:1424:48
   7: slint_interpreter::eval::load_property_helper
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:1175:11
   8: slint_interpreter::eval::eval_expression
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:152:13
   9: slint_interpreter::eval::eval_expression
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:231:23
  10: slint_interpreter::eval::eval_expression
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:318:19
  11: slint_interpreter::eval::eval_expression
             at /var/home/tobias/src/slint/internal/interpreter/eval.rs:322:30
  12: slint_interpreter::dynamic_item_tree::make_binding_eval_closure::{{closure}}
             at /var/home/tobias/src/slint/internal/interpreter/dynamic_item_tree.rs:1274:9
  13: <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call
             at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/alloc/src/boxed.rs:2032:9
  14: <i_slint_core::rtti::MaybeAnimatedPropertyInfoWrapper<Item,i_slint_core::properties::Property<T>> as i_slint_core::rtti::PropertyInfo<Item,Value>>::set_binding::set_binding_impl::{{closure}}
             at /var/home/tobias/src/slint/internal/core/rtti.rs:210:25
  15: <F as i_slint_core::properties::Binding<T>>::evaluate
             at /var/home/tobias/src/slint/internal/core/properties.rs:710:9
  16: i_slint_core::properties::Property<T>::set_binding::{{closure}}
             at /var/home/tobias/src/slint/internal/core/properties.rs:903:28
  17: <F as i_slint_core::properties::BindingCallable>::evaluate
             at /var/home/tobias/src/slint/internal/core/properties.rs:294:9
  18: i_slint_core::properties::alloc_binding_holder::evaluate::{{closure}}
             at /var/home/tobias/src/slint/internal/core/properties.rs:397:13
  19: i_slint_core::properties::CURRENT_BINDING::<impl i_slint_core::properties::CURRENT_BINDING>::set
             at /var/home/tobias/.cargo/registry/src/index.crates.io-6f17d22bba15001f/scoped-tls-hkt-0.1.4/src/lib.rs:265:25
  20: i_slint_core::properties::alloc_binding_holder::evaluate
             at /var/home/tobias/src/slint/internal/core/properties.rs:396:9
  21: i_slint_core::properties::PropertyHandle::update::{{closure}}
             at /var/home/tobias/src/slint/internal/core/properties.rs:593:29
  22: i_slint_core::properties::PropertyHandle::access
             at /var/home/tobias/src/slint/internal/core/properties.rs:498:13
  23: i_slint_core::properties::PropertyHandle::update
             at /var/home/tobias/src/slint/internal/core/properties.rs:588:22
  24: i_slint_core::properties::Property<T>::get
             at /var/home/tobias/src/slint/internal/core/properties.rs:794:18
  25: i_slint_core::items::Rectangle::background
             at /var/home/tobias/src/slint/internal/core/items.rs:251:33
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
[Info  - 12:41:36 PM] Connection to server got closed. Server will restart.
true
The Slint Language Server crashed. This is a bug.
Please open an issue on https://github.com/slint-ui/slint/issues

[hunger]

RUST_BACKTRACE=full cargo run -p slint-viewer -- /tmp/demo/test.slint gives this backtrace:

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.25s
     Running `/var/home/tobias/src/slint/target/debug/slint-viewer /tmp/demo/test.slint`
thread 'main' panicked at internal/compiler/namedreference.rs:48:34:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0:     0x55c02fd005b5 - std::backtrace_rs::backtrace::libunwind::trace::h7884d067d1055777
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x55c02fd005b5 - std::backtrace_rs::backtrace::trace_unsynchronized::h6bc4d647cdcfd833
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x55c02fd005b5 - std::sys_common::backtrace::_print_fmt::hde15b23869dacdeb
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x55c02fd005b5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h9a7c8ebfe0e5a9ea
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x55c02fd30bbb - core::fmt::rt::Argument::fmt::h12ee69ff17c60b9e
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/fmt/rt.rs:142:9
   5:     0x55c02fd30bbb - core::fmt::write::hafeb62294a20d279
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/fmt/mod.rs:1153:17
   6:     0x55c02fcfbedf - std::io::Write::write_fmt::h83162bfc67f19d63
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/io/mod.rs:1843:15
   7:     0x55c02fd0038e - std::sys_common::backtrace::_print::hd55ca7a5e2e3de7e
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x55c02fd0038e - std::sys_common::backtrace::print::he94870e87e3768e8
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x55c02fd019c9 - std::panicking::default_hook::{{closure}}::hd193b85d1d659c30
  10:     0x55c02fd01733 - std::panicking::default_hook::h6de7d4d748c8b263
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/panicking.rs:292:9
  11:     0x55c02fd01e84 - std::panicking::rust_panic_with_hook::ha4c10d4e371025d4
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/panicking.rs:789:13
  12:     0x55c02fd01d2d - std::panicking::begin_panic_handler::{{closure}}::h8d8b80cfb6d2af9a
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/panicking.rs:650:13
  13:     0x55c02fd00a79 - std::sys_common::backtrace::__rust_end_short_backtrace::hedf50fb5defff019
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/sys_common/backtrace.rs:171:18
  14:     0x55c02fd01a97 - rust_begin_unwind
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/std/src/panicking.rs:646:5
  15:     0x55c02fd2def6 - core::panicking::panic_fmt::hde3e2c796a3a5416
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/panicking.rs:72:14
  16:     0x55c02fd2df9f - core::panicking::panic::h150613825d1ad83d
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/panicking.rs:141:5
  17:     0x55c02fd2dc79 - core::option::unwrap_failed::h83da879f26f94880
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/option.rs:1984:5
  18:     0x55c02f11adc4 - core::option::Option<T>::unwrap::h8bb67adddf6d6d2e
                               at /rustc/c9f8f3438a8134a413aa5d4903e0196e44e37bbc/library/core/src/option.rs:932:21
  19:     0x55c02f11adc4 - i_slint_compiler::namedreference::NamedReference::element::he93ab89019114672
                               at /var/home/tobias/src/slint/internal/compiler/namedreference.rs:48:9
fish: Job 1, 'RUST_BACKTRACE=full cargo run -…' terminated by signal SIGABRT (Abort)

[ogoffart]

Duplicate of #1461
The issue is fairly hard to solve and will need some refactoring of the compiler to solve it.
Marking as duplicated, but thanks anyway for reporting.

[ogoffart]

Actually, re-opening because the panic could get fixed and replaced by an error just like we did for the original testcase of #1461