dioxus hello world example causes compiler panic on windows

[anderslanglands]

As title. Happens with both stable and nightly

Code

main.rs:

use dioxus::prelude::*;

fn main() {
    dioxus::desktop::launch(App);
}

fn App(cx: Scope) -> Element {
    cx.render(rsx! {
        div { "Hello, world!"}
    })
}

Cargo.toml:

[package]
name = "hello-dioxus"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
dioxus = { version = "0.1.4", features = ["desktop"] }

Meta

rustc --version --verbose:

rustc 1.57.0 (f1edd0429 2021-11-29)
binary: rustc
commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
commit-date: 2021-11-29
host: x86_64-pc-windows-msvc
release: 1.57.0
LLVM version: 13.0.0

rustc +nightly --version --verbose:

rustc 1.59.0-nightly (8f3238f89 2022-01-02)
binary: rustc
commit-hash: 8f3238f898163f09726c3d2b2cc9bafb09da26f3
commit-date: 2022-01-02
host: x86_64-pc-windows-msvc
release: 1.59.0-nightly
LLVM version: 13.0.0

Error output

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', /rustc/8f3238f898163f09726c3d2b2cc9bafb09da26f3\compiler\rustc_middle\src\ty\sty.rs:1036:9
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.59.0-nightly (8f3238f89 2022-01-02) running on x86_64-pc-windows-msvc

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

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

query stack during panic:
#0 [is_sized_raw] computing whether `[nodes::VNode<'_>]` is `Sized`
#1 [layout_of] computing layout of `&[nodes::VNode<'_>]`
end of query stack
error: could not compile `dioxus-core`
warning: build failed, waiting for other jobs to finish...
error: build failed

Backtrace

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', /rustc/8f3238f898163f09726c3d2b2cc9bafb09da26f3\compiler\rustc_middle\src\ty\sty.rs:1036:9
stack backtrace:
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 1.59.0-nightly (8f3238f89 2022-01-02) running on x86_64-pc-windows-msvc

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

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

query stack during panic:
#0 [is_sized_raw] computing whether `[nodes::VNode<'_>]` is `Sized`
#1 [layout_of] computing layout of `&[nodes::VNode<'_>]`
#2 [layout_of] computing layout of `nodes::VFragment<'_>`
#3 [layout_of] computing layout of `nodes::VNode<'_>`
#4 [layout_of] computing layout of `core::option::Option<nodes::VNode<'_>>`
end of query stack
error: could not compile `dioxus-core`
warning: build failed, waiting for other jobs to finish...
error: build failed

[Patrick-Poitras]

Can confirm bug is replicable with example above.

thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', /rustc/efec545293b9263be9edfb283a7aa66350b3acbf\compiler\rustc_middle\src\ty\sty.rs:1038:9
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.59.0-nightly (efec54529 2021-12-04) running on x86_64-pc-windows-msvc


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

query stack during panic:
#0 [is_sized_raw] computing whether `[nodes::VNode<'_>]` is `Sized`
#1 [layout_of] computing layout of `&[nodes::VNode<'_>]`
end of query stack
error: could not compile `dioxus-core`

[cbeust]

Confirmed on Windows 10 for me as well (cargo build is enough to produce the error).

[cbeust]

Including the error for completeness.

☻~/rust/dioxus $ cargo build
   Compiling dioxus-html v0.1.2 (...)
thread 'rustc' panicked at 'assertion failed: !value.has_escaping_bound_vars()', /rustc/f1edd0429582dd29cccacaf50fd134b05593bd9c\compiler\rustc_middle\src\ty\sty.rs:974:9
note: run with `RUST_BACKTRACE=1` environment variable to display a 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 1.57.0 (f1edd0429 2021-11-29) running on x86_64-pc-windows-msvc

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

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

query stack during panic:
#0 [is_sized_raw] computing whether `[nodes::VNode<'_>]` is `Sized`
#1 [layout_of] computing layout of `&[nodes::VNode<'_>]`
end of query stack
error: could not compile `dioxus-core`
warning: build failed, waiting for other jobs to finish...
error: build failed

[Patrick-Poitras]

Seems like they managed to get a patch out that fixes the issue.

With that information, I think this may be related to #89189.

[Patrick-Poitras]

I have spent the last 2 hours whittling down the entire codebase that they had, in order to have a minimal example. It's fairly weird.

use std::mem;
use std::marker::PhantomData;

struct LazyStack { }

impl Drop for LazyStack {
    fn drop(&mut self) {
        let g: *mut dyn FnMut(Option<NodeFactory<'_>>) -> Option<VNode<'_>> =
            unsafe {make_fat_ptr()};

        let clos = (unsafe { &mut *g });
        clos(None);
    }
}

unsafe fn make_fat_ptr<T: ?Sized>() -> *mut T {
    mem::MaybeUninit::<*mut T>::uninit().assume_init()
}

enum VNode<'src> {
    Fragment(&'src [VNode<'src>]),
}

struct NodeFactory<'a> {
    x : &'a PhantomData<u32>,
}

I'm not 100%, but I figure that mem::MaybeUninit::<*mut T>::uninit().assume_init() isn't supposed to be like that. Either way, this reproduces the issue.

[Patrick-Poitras]

Can someone on Windows try this as well (build as lib), because I've tried to add this to glacier, but it seems to compile there, and it seems to also compile on Rust Playground. I'm a bit at a loss.

[cbeust]

@Patrick-Poitras Can you be more specific? What do you want me (us) to try?

[anderslanglands]

@Patrick-Poitras yep your example panics for me on Windows.

[Patrick-Poitras]

@cbeust I'd like someone to try the minimal example that I've pasted above, since it doesn't compile on my machine (Windows), but it seems from the other issues thread (on dioxus) that it's a Windows-specific problem. When I've run it on linux machines, it seems to compile there.

Edit: @anderslanglands, thanks! I'll try to get a discussion going on Zulip as to what could cause this.