fix drop scope for `super let` bindings within `if let` #145342

dianne · 2025-08-13T08:40:59Z

Fixes #145328 by making non-lifetime-extended super let reuse the logic used to compute drop scopes for non-lifetime-extended temporaries.

Also fixes #145374, which regressed due to #143376 introducing if let-like scopes for match arms with guards.

Tracking issue for super let: #139076

This is a regression fix / breaking change for macros stably exposing super let, including pin! and format_args!.
Nominating to be discussed alongside #145328: @rustbot label +I-lang-nominated +I-libs-api-nominated

They now use the enclosing temporary scope as their scope, regardless of which `ScopeData` was used to mark it.

rustbot · 2025-08-13T08:41:03Z

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compiler-errors · 2025-08-13T14:58:23Z

@dianne does this need crater?

traviscross · 2025-08-13T15:38:36Z

@bors2 try

fix drop scope for `super let` bindings within `if let`

rust-bors · 2025-08-13T17:53:47Z

☀️ Try build successful (CI)
Build commit: a498031 (a4980311fb7bb9e7893708e6bd3fbbfb2819fd3d, parent: 350d0ef0ec0493e6d21cfb265cb8211a0e74d766)

compiler-errors · 2025-08-13T17:54:38Z

@craterbot check

craterbot · 2025-08-13T17:54:59Z

👌 Experiment pr-145342 created and queued.
🤖 Automatically detected try build a498031
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theemathas · 2025-08-14T03:10:58Z

How does #145374 relate to this? The code there doesn't use super let anywhere.

dianne · 2025-08-14T03:13:50Z

Format arguments, e.g. as used by write!, are also implemented in terms of super let. This is visible when printing the HIR of that test case:

f.write_fmt({
        super let args =
            (&pointee.behind_pointer(),
                &ItemIdentifier::path(&ItemIdentifier::nserror()));
        super let args =
            [format_argument::new_display(args.0),
                    format_argument::new_display(args.1)];
        format_arguments::new_v1(&["", ", "], &args)
    })

The interaction between that, old editions not treating block tail expressions as temporary drop scopes, my guard scoping PR, and the existing super let scoping bug is what caused that particular regression.

theemathas · 2025-08-15T06:01:27Z

This code causes this PR to ICE in the dropping_copy_types lint:

pub fn foo() {
    drop(format_args!("a"));
}

Error output

thread 'rustc' panicked at /Users/timch/rust/compiler/rustc_errors/src/diagnostic.rs:960:9:
assertion `left == right` failed: Span must not be empty and have no suggestion
  left: Some(SubstitutionPart { span: src/lib.rs:2:27: 2:27 (#4), snippet: "" })
 right: None
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:697:5
   1: core::panicking::panic_fmt
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panicking.rs:75:14
   2: core::panicking::assert_failed_inner
   3: assert_failed<core::option::Option<&rustc_errors::SubstitutionPart>, core::option::Option<&rustc_errors::SubstitutionPart>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panicking.rs:403:5
   4: multipart_suggestion_with_style<(), rustc_error_messages::SubdiagMessage>
             at /Users/timch/rust/compiler/rustc_errors/src/diagnostic.rs:960:9
   5: add_to_diag<()>
             at /Users/timch/rust/compiler/rustc_lint/src/lints.rs:691:10
   6: subdiagnostic<(), rustc_lint::lints::UseLetUnderscoreIgnoreSuggestion>
             at /Users/timch/rust/compiler/rustc_errors/src/diagnostic.rs:1251:23
   7: decorate_lint
             at /Users/timch/rust/compiler/rustc_lint/src/lints.rs:719:10
   8: {closure#0}<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>
             at /Users/timch/rust/compiler/rustc_lint/src/context.rs:524:23
   9: call_once<rustc_lint::context::LintContext::emit_span_lint::{closure_env#0}<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>, (&mut rustc_errors::diagnostic::Diag<()>)>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/ops/function.rs:253:5
  10: call_once<(&mut rustc_errors::diagnostic::Diag<()>), dyn core::ops::function::FnOnce<(&mut rustc_errors::diagnostic::Diag<()>), Output=()>, alloc::alloc::Global>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/alloc/src/boxed.rs:1971:9
  11: lint_level_impl
             at /Users/timch/rust/compiler/rustc_middle/src/lint.rs:427:13
  12: lint_level<rustc_lint::context::LintContext::emit_span_lint::{closure_env#0}<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>>
             at /Users/timch/rust/compiler/rustc_middle/src/lint.rs:433:5
  13: node_span_lint<rustc_span::span_encoding::Span, rustc_lint::context::LintContext::emit_span_lint::{closure_env#0}<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context.rs:3177:9
  14: opt_span_lint<rustc_span::span_encoding::Span, rustc_lint::context::LintContext::emit_span_lint::{closure_env#0}<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>>
             at /Users/timch/rust/compiler/rustc_lint/src/context.rs:637:33
  15: emit_span_lint<rustc_lint::context::LateContext, rustc_span::span_encoding::Span, rustc_lint::lints::DropCopyDiag>
             at /Users/timch/rust/compiler/rustc_lint/src/context.rs:523:14
  16: check_expr
             at /Users/timch/rust/compiler/rustc_lint/src/drop_forget_useless.rs:184:24
  17: check_expr
             at /Users/timch/rust/compiler/rustc_lint/src/passes.rs:79:23
  18: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:33:14
  19: with_lint_attrs<rustc_lint::BuiltinCombinedModuleLateLintPass, rustc_lint::late::{impl#1}::visit_expr::{closure#0}::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:59:9
  20: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:165:18
  21: maybe_grow<(), rustc_lint::late::{impl#1}::visit_expr::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/stacker-0.1.21/src/lib.rs:57:9
  22: ensure_sufficient_stack<(), rustc_lint::late::{impl#1}::visit_expr::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/stack.rs:21:5
  23: visit_expr<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:164:9
  24: visit_stmt<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:179:9
  25: walk_block<rustc_lint::late::LateContextAndPass<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_hir/src/intravisit.rs:694:5
  26: visit_block<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:240:9
  27: walk_expr<rustc_lint::late::LateContextAndPass<rustc_lint::BuiltinCombinedModuleLateLintPass>>
  28: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:167:17
  29: with_lint_attrs<rustc_lint::BuiltinCombinedModuleLateLintPass, rustc_lint::late::{impl#1}::visit_expr::{closure#0}::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:59:9
  30: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:165:18
  31: maybe_grow<(), rustc_lint::late::{impl#1}::visit_expr::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/stacker-0.1.21/src/lib.rs:57:9
  32: ensure_sufficient_stack<(), rustc_lint::late::{impl#1}::visit_expr::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/stack.rs:21:5
  33: visit_expr<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:164:9
  34: visit_body<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:120:9
  35: visit_nested_body<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:103:14
  36: visit_fn<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:196:9
  37: walk_item<rustc_lint::late::LateContextAndPass<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_hir/src/intravisit.rs:558:32
  38: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:132:17
  39: with_param_env<rustc_lint::BuiltinCombinedModuleLateLintPass, rustc_lint::late::{impl#1}::visit_item::{closure#0}::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:71:9
  40: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:130:16
  41: with_lint_attrs<rustc_lint::BuiltinCombinedModuleLateLintPass, rustc_lint::late::{impl#1}::visit_item::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:59:9
  42: visit_item<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:129:14
  43: visit_nested_item<rustc_lint::late::LateContextAndPass<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_hir/src/intravisit.rs:249:29
  44: walk_mod<rustc_lint::late::LateContextAndPass<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_hir/src/intravisit.rs:650:5
  45: process_mod<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:77:9
  46: {closure#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:399:12
  47: with_lint_attrs<rustc_lint::BuiltinCombinedModuleLateLintPass, rustc_lint::late::late_lint_mod_inner::{closure_env#0}<rustc_lint::BuiltinCombinedModuleLateLintPass>>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:59:9
  48: late_lint_mod_inner<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:393:8
  49: late_lint_mod<rustc_lint::BuiltinCombinedModuleLateLintPass>
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:367:13
  50: lint_mod
             at /Users/timch/rust/compiler/rustc_lint/src/lib.rs:151:5
  51: {closure#0}
             at /Users/timch/rust/compiler/rustc_query_impl/src/plumbing.rs:294:9
      [... omitted 33 frames ...]
  52: query_ensure<rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalModDefId, rustc_middle::query::erase::Erased<[u8; 0]>>>
             at /Users/timch/rust/compiler/rustc_middle/src/query/plumbing.rs:198:9
  53: lint_mod
             at /Users/timch/rust/compiler/rustc_middle/src/query/plumbing.rs:233:9
  54: {closure#0}
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:474:70
  55: {closure#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_middle/src/hir/map.rs:476:13
  56: {closure#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:181:30
  57: call_once<(), rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure#1}::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panic/unwind_safe.rs:272:9
  58: do_call<core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure#1}::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:589:40
  59: catch_unwind<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure#1}::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:552:19
  60: catch_unwind<core::panic::unwind_safe::AssertUnwindSafe<rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure#1}::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panic.rs:359:14
  61: run<(), rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure#1}::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:23:9
  62: {closure#1}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:181:23
  63: for_each<rustc_hir::hir_id::OwnerId, rustc_data_structures::sync::parallel::par_for_each_in::{closure#0}::{closure_env#1}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/slice/iter/macros.rs:277:21
  64: {closure#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:180:27
  65: parallel_guard<(), rustc_data_structures::sync::parallel::par_for_each_in::{closure_env#0}<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:39:15
  66: par_for_each_in<&rustc_hir::hir_id::OwnerId, &[rustc_hir::hir_id::OwnerId], rustc_middle::hir::map::{impl#3}::par_hir_for_each_module::{closure_env#0}<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:175:5
  67: par_hir_for_each_module<rustc_lint::late::check_crate::{closure#1}::{closure#0}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_middle/src/hir/map.rs:475:9
  68: {closure#0}
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:474:21
  69: run<(), rustc_lint::late::check_crate::{closure#1}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/profiling.rs:844:9
  70: time<(), rustc_lint::late::check_crate::{closure#1}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_session/src/utils.rs:16:50
  71: {closure#1}
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:472:22
  72: call_once<(), rustc_lint::late::check_crate::{closure_env#1}>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panic/unwind_safe.rs:272:9
  73: do_call<core::panic::unwind_safe::AssertUnwindSafe<rustc_lint::late::check_crate::{closure_env#1}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:589:40
  74: catch_unwind<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_lint::late::check_crate::{closure_env#1}>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:552:19
  75: catch_unwind<core::panic::unwind_safe::AssertUnwindSafe<rustc_lint::late::check_crate::{closure_env#1}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panic.rs:359:14
  76: run<(), rustc_lint::late::check_crate::{closure_env#1}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:23:9
  77: {closure#0}<rustc_lint::late::check_crate::{closure_env#0}, rustc_lint::late::check_crate::{closure_env#1}, (), ()>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:53:23
  78: parallel_guard<(core::option::Option<()>, core::option::Option<()>), rustc_data_structures::sync::parallel::serial_join::{closure_env#0}<rustc_lint::late::check_crate::{closure_env#0}, rustc_lint::late::check_crate::{closure_env#1}, (), ()>>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:39:15
  79: serial_join<rustc_lint::late::check_crate::{closure_env#0}, rustc_lint::late::check_crate::{closure_env#1}, (), ()>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:51:18
  80: join<rustc_lint::late::check_crate::{closure_env#0}, rustc_lint::late::check_crate::{closure_env#1}, (), ()>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:132:9
  81: check_crate
             at /Users/timch/rust/compiler/rustc_lint/src/late.rs:464:5
  82: {closure#0}
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1165:29
  83: run<(), rustc_interface::passes::analysis::{closure#0}::{closure#2}::{closure#0}::{closure#2}::{closure#1}::{closure#0}::{closure#2}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/profiling.rs:844:9
  84: time<(), rustc_interface::passes::analysis::{closure#0}::{closure#2}::{closure#0}::{closure#2}::{closure#1}::{closure#0}::{closure#2}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_session/src/utils.rs:16:50
  85: {closure#2}
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1164:30
  86: call_once<(), rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure#0}::{closure_env#2}>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panic/unwind_safe.rs:272:9
  87: do_call<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure#0}::{closure_env#2}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:589:40
  88: catch_unwind<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure#0}::{closure_env#2}>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:552:19
  89: catch_unwind<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure#0}::{closure_env#2}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panic.rs:359:14
  90: run<(), rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure#0}::{closure_env#2}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:23:9
  91: {closure#0}
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:88:29
  92: parallel_guard<(), rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:39:15
  93: {closure#0}
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1152:17
  94: call_once<(), rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure_env#0}>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panic/unwind_safe.rs:272:9
  95: do_call<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure_env#0}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:589:40
  96: catch_unwind<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure_env#0}>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:552:19
  97: catch_unwind<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure_env#0}>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panic.rs:359:14
  98: run<(), rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:23:9
  99: {closure#1}
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:87:27
 100: parallel_guard<(), rustc_interface::passes::analysis::{closure#0}::{closure_env#1}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/sync/parallel.rs:39:15
 101: {closure#0}
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1148:9
 102: run<(), rustc_interface::passes::analysis::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_data_structures/src/profiling.rs:844:9
 103: time<(), rustc_interface::passes::analysis::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_session/src/utils.rs:16:50
 104: analysis
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1147:10
 105: {closure#0}
             at /Users/timch/rust/compiler/rustc_query_impl/src/plumbing.rs:294:9
      [... omitted 33 frames ...]
 106: query_ensure<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>>
             at /Users/timch/rust/compiler/rustc_middle/src/query/plumbing.rs:198:9
 107: analysis
             at /Users/timch/rust/compiler/rustc_middle/src/query/plumbing.rs:233:9
 108: {closure#2}
             at /Users/timch/rust/compiler/rustc_driver_impl/src/lib.rs:370:29
 109: {closure#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1006:27
 110: {closure#1}<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context.rs:1546:37
 111: {closure#0}<rustc_middle::ty::context::{impl#21}::enter::{closure_env#1}<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context/tls.rs:60:9
 112: try_with<core::cell::Cell<*const ()>, rustc_middle::ty::context::tls::enter_context::{closure_env#0}<rustc_middle::ty::context::{impl#21}::enter::{closure_env#1}<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/thread/local.rs:315:12
 113: with<core::cell::Cell<*const ()>, rustc_middle::ty::context::tls::enter_context::{closure_env#0}<rustc_middle::ty::context::{impl#21}::enter::{closure_env#1}<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/thread/local.rs:279:20
 114: enter_context<rustc_middle::ty::context::{impl#21}::enter::{closure_env#1}<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>, core::option::Option<rustc_interface::queries::Linker>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context/tls.rs:57:9
 115: enter<rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, core::option::Option<rustc_interface::queries::Linker>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context.rs:1546:9
 116: create_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure_env#0}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>>
             at /Users/timch/rust/compiler/rustc_middle/src/ty/context.rs:1751:13
 117: {closure#2}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:973:9
 118: call_once<rustc_interface::passes::create_and_enter_global_ctxt::{closure_env#2}<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>, (&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy, alloc::alloc::Global>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2})>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/ops/function.rs:253:5
 119: call_once<(&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy, alloc::alloc::Global>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}), dyn core::ops::function::FnOnce<(&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy, alloc::alloc::Global>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}), Output=core::option::Option<rustc_interface::queries::Linker>>, alloc::alloc::Global>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/alloc/src/boxed.rs:1971:9
 120: create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure_env#2}>
             at /Users/timch/rust/compiler/rustc_interface/src/passes.rs:1014:5
 121: {closure#0}
             at /Users/timch/rust/compiler/rustc_driver_impl/src/lib.rs:343:22
 122: {closure#0}<(), rustc_driver_impl::run_compiler::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_interface/src/interface.rs:525:80
 123: call_once<(), rustc_interface::interface::run_compiler::{closure#1}::{closure_env#0}<(), rustc_driver_impl::run_compiler::{closure_env#0}>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/core/src/panic/unwind_safe.rs:272:9
 124: do_call<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler::{closure#1}::{closure_env#0}<(), rustc_driver_impl::run_compiler::{closure_env#0}>>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:589:40
 125: catch_unwind<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler::{closure#1}::{closure_env#0}<(), rustc_driver_impl::run_compiler::{closure_env#0}>>>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panicking.rs:552:19
 126: catch_unwind<core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler::{closure#1}::{closure_env#0}<(), rustc_driver_impl::run_compiler::{closure_env#0}>>, ()>
             at /rustc/788da80fcfcef3f34c90def5baa32813e39a1a41/library/std/src/panic.rs:359:14
 127: {closure#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>
             at /Users/timch/rust/compiler/rustc_interface/src/interface.rs:525:23
 128: {closure#0}<rustc_interface::interface::run_compiler::{closure_env#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>, ()>
             at /Users/timch/rust/compiler/rustc_interface/src/util.rs:199:17
 129: {closure#0}<rustc_interface::util::run_in_thread_pool_with_globals::{closure_env#0}<rustc_interface::interface::run_compiler::{closure_env#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>, ()>, ()>
             at /Users/timch/rust/compiler/rustc_interface/src/util.rs:153:24
 130: set<rustc_span::SessionGlobals, rustc_interface::util::run_in_thread_with_globals::{closure#0}::{closure#0}::{closure_env#0}<rustc_interface::util::run_in_thread_pool_with_globals::{closure_env#0}<rustc_interface::interface::run_compiler::{closure_env#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>, ()>, ()>, ()>
             at /Users/timch/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/scoped-tls-1.0.1/src/lib.rs:137:9
 131: create_session_globals_then<(), rustc_interface::util::run_in_thread_with_globals::{closure#0}::{closure#0}::{closure_env#0}<rustc_interface::util::run_in_thread_pool_with_globals::{closure_env#0}<rustc_interface::interface::run_compiler::{closure_env#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>, ()>, ()>>
             at /Users/timch/rust/compiler/rustc_span/src/lib.rs:146:21
 132: {closure#0}<rustc_interface::util::run_in_thread_pool_with_globals::{closure_env#0}<rustc_interface::interface::run_compiler::{closure_env#1}<(), rustc_driver_impl::run_compiler::{closure_env#0}>, ()>, ()>
             at /Users/timch/rust/compiler/rustc_interface/src/util.rs:149:17
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: please attach the file at `/Users/timch/foo/rustc-ice-2025-08-15T06_05_34-7312.txt` to your bug report

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

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

query stack during panic:
#0 [lint_mod] linting top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `foo` (lib)

Caused by:
  process didn't exit successfully: `/Users/timch/.rustup/toolchains/stage1/bin/rustc --crate-name foo --edition=2024 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=72 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 -C split-debuginfo=unpacked --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=8c501619d3290ba0 -C extra-filename=-24fb7592114348d8 --out-dir /Users/timch/foo/target/debug/deps -C incremental=/Users/timch/foo/target/debug/incremental -L dependency=/Users/timch/foo/target/debug/deps` (exit status: 101)

dianne · 2025-08-15T06:31:46Z

Thanks for testing this! That's also a separate bug; it ICEs with debug asserts on before my commits. Here's what it looks like on stable/nightly with debug asserts off:

help: use `let _ = ...` to ignore the expression or result
  |
2 -     drop(format_args!("a"));
2 +     drop(let _ = );
  |

Edit: To make sure there's no interaction, I've recompiled this PR with debug asserts off and am getting the drop(let _ = ); suggestion instead of ICE. I'm not sure if there's a way to test non-regression there in CI though; rebasing onto a fix for that bug would work, but that should probably be kept out of a hypothetical backport.

craterbot · 2025-08-16T05:02:39Z

🎉 Experiment pr-145342 is completed!
📊 3 regressed and 6 fixed (681861 total)
📰 Open the summary report.

⚠️ If you notice any spurious failure please add them to the denylist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

theemathas · 2025-08-16T05:08:36Z

The crater run is clean. No relevant regressions or fixes.

theemathas · 2025-08-16T07:46:22Z

Summary of everything so far

I am naming each of the regressions: A, B, C, D, so it's easier to refer to them in the future. For each of them, I give a link to a reproducer of the bug, and I describe when the regression occurred, the prerequisites for code to be affected by the bug, the likelihood (in my opinion) of real user code being affected, and the impact of the bug on such code.

Regression A: pin!() has incorrect/unexpected drop order inside if-let. #145328 (comment)
- When: Regressed from 1.87.0 to 1.88.0, presumably in Implement pin!() using super let #139114
- Prerequisites: Use pin!(HasDrop) in an if let condition, and use the entire if let expression as a subexpression of something else.
- Likelihood: Unlikely to affect real code, since it requires a rather specific and strange set of conditions.
- Impact: Silent miscompile. I think it probably can also cause a compile error.
Regression B: fix drop scope for super let bindings within if let #145342 (comment)
- When: Regressed from 1.88.0 to 1.89.0, presumably in Allow storing format_args!() in a variable #140748
- Prerequisites: In an if let condition, use a write!()-like macro to format two or more values, one of which has a destructor and references a temporary.
- Likelihood: I'm not sure. It requires some specific conditions, but those conditions are not so rare.
- Impact: Compile error. I do not know whether this can cause a silent miscompile or not.
Regression C (Not fixed by this PR): Regression: format_args!() no longer lifetime-extends some temporaries. #145422
- When: Regressed from 1.88.0 to 1.89.0, presumably in Allow storing format_args!() in a variable #140748
- Prerequisites: Use format_args!() to format a value that has a destructor. Then, store the result into a variable. (The conditions are more specific than this, but I'm not sure what exactly they are.)
- Likelihood: Very unlikely to affect real code, since there's no reason to store a format_args!() into a variable in versions 1.88.0 or earlier. Such variables became potentially usable only since version 1.89.0.
- Impact: Compile error. I do not know whether this can cause a silent miscompile or not.
Regression D: Regression when dropping temporary value in match in older editions #145374
- When: Regressed from 1.89.0 to nightly, in add a scope for if let guard temporaries and bindings #143376
- Prerequisites: Inside a match arm that has an if guard, use a write!-like macro to format two or more values, one of which has a destructor and references a temporary. This macro call is the last expression in a block. Only affects edition 2021 or earlier. (Edit: see fix drop scope for super let bindings within if let #145342 (comment) for corrections)
- Likelihood: Already affected real code.
- Impact: Compile error. I do not know whether this can cause a silent miscompile or not.

Additionally, there's:

Non-regression bug: pin!() has incorrect/unexpected drop order inside if-let. #145328 (comment)
- When: Affects code since version 1.88.0, due to let-chains stabilizing in Stabilize let chains in the 2024 edition #132833
- Prerequisites: In a let-chain, use pin!(HasDrop) in the second link or later of the chain, and have a temporary with a destructor earlier in the chain.
- Likelihood: I'm not sure. It requires some specific conditions, but those conditions are not so rare.
- Impact: Silent miscompile. I think it probably can also cause a compile error.

dianne · 2025-08-16T08:07:54Z

With regard to regression D, I imagine it affects edition 2024 as well for match arms where the arm body isn't wrapped in a block expression. It's caused by #143376 extending the surface area of the bug underlying regressions A/B to all match arms with guards where the super let-based macro isn't wrapped in a more deeply nested temporary destruction scope (e.g. a block tail expression in edition 2024). I'm sure you can also get a silent miscompile out of it if you're relying on things like temporary drop order for tuple constructor expressions and constructing a tuple with a write! call in it, but that feels unlikely in real code.

rfcbot · 2025-08-19T15:06:36Z

🔔 This is now entering its final comment period, as per the review above. 🔔

Amanieu · 2025-08-19T15:13:12Z

We discussed this in the @rust-lang/libs-api meeting and we're happy to defer to lang for this issue.

apiraino · 2025-08-21T14:27:28Z

Stable backport declined as per compiler team on Zulip.

We reviewed again the stable backport and our concerns still stand.

@rustbot label -stable-nominated

jieyouxu · 2025-08-23T10:12:26Z

@craterbot run mode=check-only crates=https://crater-reports.s3.amazonaws.com/pr-145342/retry-regressed-list.txt

craterbot · 2025-08-23T10:12:36Z

👌 Experiment pr-145342-1 created and queued.
🤖 Automatically detected try build a498031
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

dianne · 2025-08-23T13:02:02Z

Something to consider for the FCP: this PR does not make the identity in #145342 (comment) hold. See #145784 (comment) for how it fails to hold in non-extending expressions, due to super let extending the lifetimes of its initializer's temporaries, effectively ignoring block tail expressions' temporary drop scopes. If we want that identity, I think we'd need to rework non-extended super let to have more restrictive temporary lifetime extension rules. Alternatively, whatever identity is used for reasoning about super let may need to account for it having differing meanings in different contexts.

My personal judgment is that that issue is orthogonal to the bug this PR fixes: this PR fixes super let's bindings' lifetimes, whereas the identity fails to hold in non-extending expressions due to super let's initializer's temporaries' lifetimes. However, if the FCP is for super let behaving a particular way, then this PR alone doesn't achieve that.

dianne added 2 commits August 13, 2025 01:38

add a test with incorrect if let-super let drop order

bbf08d8

fix scope of super let bindings within if let

8fc3938

They now use the enclosing temporary scope as their scope, regardless of which `ScopeData` was used to mark it.

rustbot assigned jackh726 Aug 13, 2025

dianne force-pushed the if-let-super-let branch from f7b3d29 to 8fc3938 Compare August 13, 2025 08:41

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rust-bors bot added a commit that referenced this pull request Aug 13, 2025

Auto merge of #145342 - dianne:if-let-super-let, r=<try>

a498031

fix drop scope for `super let` bindings within `if let`

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 13, 2025

dianne mentioned this pull request Aug 14, 2025

Regression when dropping temporary value in match in older editions #145374

Open

rustbot added the stable-nominated Nominated for backporting to the compiler in the stable channel. label Aug 14, 2025

compiler-errors added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Aug 14, 2025

traviscross added T-lang Relevant to the language team I-lang-radar Items that are on lang's radar and will need eventual work or consideration. and removed T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Aug 14, 2025

theemathas mentioned this pull request Aug 15, 2025

Regression: format_args!() no longer lifetime-extends some temporaries. #145422

Open

theemathas mentioned this pull request Aug 15, 2025

dropping_copy_types lint gives wrong suggestion with format_args! #145427

Closed

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Aug 16, 2025

traviscross mentioned this pull request Aug 17, 2025

pin!() has incorrect/unexpected drop order inside if-let. #145328

Open

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Aug 19, 2025

Amanieu removed the I-libs-api-nominated Nominated for discussion during a libs-api team meeting. label Aug 19, 2025

traviscross removed I-lang-nominated Nominated for discussion during a lang team meeting. P-lang-drag-0 Lang team prioritization drag level 0.https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang. labels Aug 20, 2025

rustbot removed the stable-nominated Nominated for backporting to the compiler in the stable channel. label Aug 21, 2025

theemathas mentioned this pull request Aug 23, 2025

pin!() changed temporary lifetime extension behavior in version 1.88.0 #145784

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craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 23, 2025

fix drop scope for super let bindings within if let #145342

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fix drop scope for super let bindings within if let #145342

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fix drop scope for `super let` bindings within `if let` #145342

fix drop scope for `super let` bindings within `if let` #145342

dianne commented Aug 13, 2025 •

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dianne commented Aug 14, 2025 •

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apiraino commented Aug 21, 2025 •

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dianne commented Aug 23, 2025 •

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