by_move_body.rs:275:21: There should be at least a single deref for an upvar local initialization, found []

[TeamDman]

Code

This compiler error appeared when I tried to wrap my function in an async block so I could use inner returns without returning from the parent fn; I want to call .wrap_err from eyre crate on whatever is returning so I can attach some information.

I had previously attempted to use the unstable try_blocks feature, but I think my return Err and bail! usage in the body was returning from the fn instead of the try block.

removing the wrapping async closure fixes the rustc-ice compiler error.

AAFC-Cloud/Cloud-Terrastodon@fc55eb8

diff --git a/rust/crates/command/src/command.rs b/rust/crates/command/src/command.rs
index 10f645d..9c52993 100644
--- a/rust/crates/command/src/command.rs
+++ b/rust/crates/command/src/command.rs
@@ -550,7 +550,7 @@ impl CommandBuilder {
     #[async_recursion]
     #[track_caller]
     pub async fn run_raw(&self) -> Result<CommandOutput> {
-        let result: eyre::Result<CommandOutput> = (async ||{
+        // let result: eyre::Result<CommandOutput> = (async ||{
             // Check cache
             match self.get_cached_output().await {
                 Ok(None) => {}
@@ -685,10 +685,10 @@ impl CommandBuilder {
 
             // Return success
             Ok(output)
-        })().await;
-        result
-            .wrap_err(format!("Invoking command `{}`", self.summarize()))
-            .wrap_err(format!("Called from {}", std::panic::Location::caller()))
+        // })().await;
+        // result
+        //     .wrap_err(format!("Invoking command `{}`", self.summarize()))
+        //     .wrap_err(format!("Called from {}", std::panic::Location::caller()))
     }
 
     pub async fn run<T>(&self) -> Result<T>

here is the permalink to the relevant file at the commit where the compiler error manifests

https://github.com/AAFC-Cloud/Cloud-Terrastodon/blob/73709d3861d008195bb14824e1fc1bb0f03c1940/rust/crates/command/src/command.rs#L553

cd cloud_terrastodon/rust
cargo build

rustc-ice-2025-03-14T14_54_32-34820.txt

Meta

rustc --version --verbose:

rustc 1.87.0-nightly (f8a913b13 2025-02-23)
binary: rustc
commit-hash: f8a913b1381e90379c7ca63ac2b88b9518936628
commit-date: 2025-02-23
host: x86_64-pc-windows-msvc
release: 1.87.0-nightly
LLVM version: 20.1.0

Error output

cargo build 2>&1 | set-clipboard

Backtrace

Compiling cloud_terrastodon_core_command v0.1.0 (C:\Users\redacted\source\repos\cloud-terrastodon\rust\crates\command)
error: internal compiler error: compiler\rustc_mir_transform\src\coroutine\by_move_body.rs:275:21: There should be at least a single deref for an upvar local initialization, found []
System.Management.Automation.RemoteException
System.Management.Automation.RemoteException
thread 'rustc' panicked at compiler\rustc_mir_transform\src\coroutine\by_move_body.rs:275:21:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   3: <rustc_middle::ty::consts::Const>::to_value
   4: <rustc_middle::ty::consts::Const>::to_value
   5: rustc_middle::util::bug::bug_fmt
   6: <rustc_mir_transform::coroutine::by_move_body::MakeByMoveBody as rustc_middle::mir::visit::MutVisitor>::visit_place
   7: rustc_mir_transform::coroutine::by_move_body::coroutine_by_move_body_def_id
   8: <rustc_query_impl::plumbing::QueryCtxt as rustc_query_system::query::QueryContext>::depth_limit_error
   9: RINvNtNtCs9MBRoav2AsG_18rustc_query_system5query8plumbing17try_execute_queryINtCsk7G2C29L4pP_16rustc_query_impl13DynamicConfigINtNtB4_6caches10DefIdCacheINtNtNtCsiF0U1sNts3Z_12rustc_middle5query5erase6ErasedAhj8_EEKb0_KB3r_KB3r_ENtNtB1f_8plumbing9QueryCtxt
  10: <rustc_span::def_id::DefIndex as rustc_query_impl::profiling_support::SpecIntoSelfProfilingString>::spec_to_self_profile_string
  11: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  12: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  13: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  14: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  15: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  16: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  17: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  18: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  19: <std::io::buffered::bufwriter::BufWriter<std::io::stdio::Stdout>>::write_all_cold
  20: <rayon_core::registry::WorkerThread>::wait_until_cold
  21: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  22: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  23: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  24: core::slice::sort::unstable::heapsort::heapsort::<(alloc::string::String, core::option::Option<alloc::string::String>), <(alloc::string::String, core::option::Option<alloc::string::String>) as core::cmp::PartialOrd>::lt>
  25: <std::io::buffered::bufwriter::BufWriter<std::io::stdio::Stdout>>::write_all_cold
  26: <rayon_core::registry::WorkerThread>::wait_until_cold
  27: <rayon_core::registry::ThreadBuilder>::run
  28: core::slice::sort::unstable::heapsort::heapsort::<((rustc_lint_defs::Level, &str), usize), <((rustc_lint_defs::Level, &str), usize) as core::cmp::PartialOrd>::lt>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
System.Management.Automation.RemoteException
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
System.Management.Automation.RemoteException
note: please make sure that you have updated to the latest nightly
System.Management.Automation.RemoteException
note: please attach the file at `C:\Users\redacted\source\repos\cloud-terrastodon\rust\rustc-ice-2025-03-14T14_57_11-50832.txt` to your bug report
System.Management.Automation.RemoteException
note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C linker=rust-lld.exe -C incremental=[REDACTED] -Z share-generics=n -Z threads=0
System.Management.Automation.RemoteException
note: some of the compiler flags provided by cargo are hidden
System.Management.Automation.RemoteException
query stack during panic:
#0 [coroutine_by_move_body_def_id] looking up the coroutine by-move body for `command::<impl at crates\command\src\command.rs:288:1: 288:20>::run_raw::{closure#0}::{closure#0}::{closure#0}`
#1 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `cloud_terrastodon_core_command` (lib)
System.Management.Automation.RemoteException
Caused by:
  process didn't exit successfully: `C:\Users\redacted\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\bin\rustc.exe --crate-name cloud_terrastodon_core_command --edition=2021 crates\command\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --check-cfg cfg(docsrs,test) --check-cfg "cfg(feature, values())" -C metadata=7558873a441101e7 -C extra-filename=-906ad886c3cb402d --out-dir C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps -C linker=rust-lld.exe -C incremental=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\incremental -L dependency=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps --extern async_recursion=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\async_recursion-24df221e7790a2db.dll --extern bstr=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libbstr-82862611855a3537.rmeta --extern chrono=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libchrono-8ee824a437ee4af8.rmeta --extern cloud_terrastodon_core_config=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libcloud_terrastodon_core_config-45cda0b2a2da8de7.rmeta --extern cloud_terrastodon_core_pathing=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libcloud_terrastodon_core_pathing-8bbdaf14ed44524a.rmeta --extern eyre=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libeyre-eb83050ece3d9ca1.rmeta --extern humantime=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libhumantime-045845348c46c495.rmeta --extern serde=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libserde-54f8f08d0ba9b293.rmeta --extern serde_json=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libserde_json-eec54a34af6fe8ed.rmeta --extern tempfile=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libtempfile-cc63fcd40fb8f7fc.rmeta --extern tokio=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libtokio-5857200c6177bf15.rmeta --extern tracing=C:\Users\redacted\source\repos\cloud-terrastodon\rust\target\debug\deps\libtracing-c4553737279fd8ba.rmeta -Zshare-generics=n -Zthreads=0 -L native=C:\Users\redacted\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\windows_x86_64_msvc-0.52.6\lib -L native=C:\Users\redacted\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\windows_x86_64_msvc-0.48.5\lib` (exit code: 101)

---

I tried getting a smaller reproduction but was unsuccessful. The following code builds and runs without errors.

This compiles and runs properly

use eyre::Context;

#[tokio::main]
async fn main() -> eyre::Result<()> {
    println!("Hello, world!");
    let bruh = Bruh {
        name: "hehe".to_string(),
    };
    // Call once; if it recurses, you might see the ICE.
    bruh.bruh().await?;
    Ok(())
}

struct Bruh {
    pub name: String,
}

impl Bruh {
    #[async_recursion::async_recursion]
    #[track_caller]
    pub async fn bruh(&self) -> eyre::Result<i32> {
        let result: eyre::Result<i32> = (async || {
            println!("Level 1: {}", self.name);
            // Nest a second async closure:
            let inner = async || {
                println!("Level 2: {}", self.name);
                // Nest a third async closure:
                let inner_most = async || {
                    println!("Level 3: {}", self.name);
                    Ok(1)
                };
                inner_most().await
            };
            inner().await
        })()
        .await;
        result.wrap_err(format!("Called from {}", std::panic::Location::caller()))
    }
}

/*

[dependencies]
async-recursion = "1.1.1"
eyre = "0.6.12"
tokio = { version = "1.44.1", features = ["full"] }

*/

[cyrgani]

reduction:

enum Foo {
    A,
    B,
}

fn run_raw(f: &Foo) {
    async || match f {
        Foo::B if true => {
            run_raw(f);
        }
        _ => {}
    };
}

@rustbot label S-has-mcve F-async_closure