compiler/rustc_borrowck/src/borrow_set.rs:250:17: found two uses for 2-phase borrow temporary

[iduanyingjie]

Code

trait Cut {
    fn floor(&mut self) -> (Option<TransDataType>, Bson)
    where
        Self: Serialize,
    {
        match serde_json::to_string(&self) {
            Ok(json) => match json.len() {
                len if len > MAX_VARCHAR_SIZE => {
                    (Some(TransDataType::Varchar(MAX_VARCHAR_SIZE)), self.cut())
                }
                len => (
                    Some(TransDataType::Varchar(varchar_size(len))),
                    Bson::String(json),
                ),
            },
            Err(e) => {
                tracing::error!(?e);
                (None, Bson::Null)
            }
        }
    }
    fn cut(&mut self) -> Bson;
}

impl Cut for Vec<Bson> {
    /// When the size of the JSON array string exceeds 65535, it needs to be trimmed so that the length is less than 65535;<br>
    /// Discard the largest element in the array, and then recursively repeat the judgment
    fn cut(&mut self) -> Bson {
        let remove_index = self
            .iter()
            .enumerate()
            .map(|(idx, value)| {
                (
                    idx,
                    serde_json::to_string(value)
                        .map(|s| s.len())
                        .unwrap_or(usize::MAX),
                )
            })
            .max_by(|a, b| a.1.cmp(&b.1))
            .map(|(idx, _)| idx);

        if let Some(remove_index) = remove_index {
            let remove_value = self.remove(remove_index);
            tracing::warn!(?remove_index, ?remove_value, "Cut the BSON array length");
        }

        match serde_json::to_string(&self) {
            Ok(json) if json.len() > MAX_VARCHAR_SIZE => become self.cut(),
            Ok(json) => Bson::String(json),
            Err(e) => {
                tracing::error!(?e);
                Bson::Null
            }
        }
    }
}

impl Cut for Document {
    /// When the size of the JSON object string exceeds 65535, it needs to be trimmed so that the length is less than 65535;<br>
    /// Discard the largest element in the array, and then recursively repeat the judgment
    fn cut(&mut self) -> Bson {
        let replace_key = self
            .iter()
            .map(|(key, value)| {
                (
                    key,
                    serde_json::to_string(value)
                        .map(|s| s.len())
                        .unwrap_or(usize::MAX),
                )
            })
            .max_by(|a, b| a.1.cmp(&b.1))
            .map(|(k, _)| k.to_string());

        if let Some(replace_key) = replace_key {
            tracing::warn!(
                "Replace the value of the largest field: {} in the BSON object as ...",
                replace_key
            );
            let _ = self.insert(replace_key, Bson::String("...".to_string()));
        }

        match serde_json::to_string(&self) {
            Ok(json) if json.len() > MAX_VARCHAR_SIZE => become self.cut(),
            Ok(json) => Bson::String(json),
            Err(e) => {
                tracing::error!(?e);
                Bson::Null
            }
        }
    }
}

Meta

rustc --version --verbose:

rustc 1.82.0-nightly (cefe1dcef 2024-07-22)
binary: rustc
commit-hash: cefe1dcef0e21f4d0c8ea856ad61c1936dfb7913
commit-date: 2024-07-22
host: x86_64-unknown-linux-gnu
release: 1.82.0-nightly
LLVM version: 18.1.7

Error output

internal compiler error: compiler/rustc_borrowck/src/borrow_set.rs:250:17: found two uses for 2-phase borrow temporary _179: bb204[0] and bb205[0]

Backtrace

warning: the feature `explicit_tail_calls` is incomplete and may not be safe to use and/or cause compiler crashes
 --> src/lib.rs:8:12
  |
8 | #![feature(explicit_tail_calls)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #112788 <https://github.com/rust-lang/rust/issues/112788> for more information
  = note: `#[warn(incomplete_features)]` on by default

error: internal compiler error: compiler/rustc_borrowck/src/borrow_set.rs:250:17: found two uses for 2-phase borrow temporary _234: bb210[0] and bb211[0]
   --> src/trans/bson.rs:142:58
    |
142 |             Ok(json) if json.len() > MAX_VARCHAR_SIZE => become self.cut(),
    |                                                          ^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at compiler/rustc_borrowck/src/borrow_set.rs:250:17:
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_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: <rustc_borrowck::borrow_set::BorrowSet>::build
   8: rustc_borrowck::do_mir_borrowck
      [... omitted 1 frame ...]
   9: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  10: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/home/iduanyingjie/Projects/rust/data-mongodb2redshift/rustc-ice-2024-07-23T13_38_17-80983.txt` to your bug report

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

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

query stack during panic:
#0 [mir_borrowck] borrow-checking `trans::bson::<impl at src/trans/bson.rs:118:1: 118:23>::cut`
#1 [analysis] running analysis passes on this crate
end of query stack
error: internal compiler error: compiler/rustc_borrowck/src/borrow_set.rs:250:17: found two uses for 2-phase borrow temporary _179: bb204[0] and bb205[0]
   --> src/trans/bson.rs:178:58
    |
178 |             Ok(json) if json.len() > MAX_VARCHAR_SIZE => become self.cut(),
    |                                                          ^^^^^^^^^^^^^^^^^

thread 'rustc' panicked at compiler/rustc_borrowck/src/borrow_set.rs:250:17:
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_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: <rustc_borrowck::borrow_set::BorrowSet>::build
   8: rustc_borrowck::do_mir_borrowck
      [... omitted 1 frame ...]
   9: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  10: rustc_interface::interface::run_compiler::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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: please make sure that you have updated to the latest nightly

note: please attach the file at `/home/iduanyingjie/Projects/rust/data-mongodb2redshift/rustc-ice-2024-07-23T13_38_17-80983.txt` to your bug report

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

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

query stack during panic:
#0 [mir_borrowck] borrow-checking `trans::bson::<impl at src/trans/bson.rs:152:1: 152:22>::cut`
#1 [analysis] running analysis passes on this crate
end of query stack
warning: `mongodb2redshift` (lib) generated 1 warning
error: could not compile `mongodb2redshift` (lib); 1 warning emitted

[theemathas]

Could you provide enough code that would be needed to compile and reproduce the issue?

@rustbot labels +S-needs-repro

[WaffleLapkin]

@iduanyingjie note that explicit_tail_calls is an incomplete feature and not ready yet for a real use. I'd recommend you do not use it until it is properly implemented.

still, it would be nice to see a reproducible example, as this is not an error I'd expect to see.

[cyrgani]

Reduced example:

#![feature(explicit_tail_calls)]
fn cut(x: &mut ()) {
    if let Some(_) = Some(Box::new(())) {
        become cut(x);
    }
}

[lqd]

The repro ICEs on beta even without a feature gate.

[WaffleLapkin]

@lqd the ICEs without a feature gate is more a general but that we continue complication even if the gate is not enabled, not necessarily specific to explicit tail calls

[WaffleLapkin]

Minimized a little bit more:

#![feature(explicit_tail_calls)]
fn f(x: &mut ()) {
    let _y = String::new();
    become f(x);
}