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Allow non-Copy unit constructors in array repeat exprs - #165621

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Jules-Bertholet:unit-constructor-repeat
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Allow non-Copy unit constructors in array repeat exprs#165621
Jules-Bertholet wants to merge 2 commits into
rust-lang:mainfrom
Jules-Bertholet:unit-constructor-repeat

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@Jules-Bertholet

@Jules-Bertholet Jules-Bertholet commented Nov 7, 2026

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Fixes #80890, fixes #139642

Depends on #165614

@rustbot label A-array

@rustbot rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. A-array Area: `[T; N]` labels Nov 7, 2026
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rust-log-analyzer commented Nov 7, 2026

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The job test-aarch64-gnu-llvm-22-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot) 
---- [ui] tests/ui/limits/huge-enum.rs#no-debuginfo stdout ----

error in revision `no-debuginfo`: Error: expected failure status (Some(1)) but received status Some(101).
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/limits/huge-enum.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--cfg" "no_debuginfo" "--check-cfg" "cfg(test,FALSE,no_debuginfo,full_debuginfo)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/limits/huge-enum.no-debuginfo" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2015" "-Cdebuginfo=0"
stdout: none
--- stderr -------------------------------

thread 'rustc' (91806) panicked at compiler/rustc_const_eval/src/const_eval/valtrees.rs:329:74:
called `Result::unwrap()` on an `Err` value: SizeOverflow(std::option::Option<[u32; 576460752303423487_usize]>)
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed::unwrap_failed_inner
   3: core::result::unwrap_failed::<&rustc_middle::ty::layout::LayoutError>
   4: rustc_const_eval::const_eval::valtrees::valtree_to_const_value
   5: <rustc_const_eval::provide::{closure#1} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_middle::ty::consts::valtree::Value)>>::call_once
      [... omitted 2 frames ...]
   6: <rustc_const_eval::interpret::eval_context::InterpCx<rustc_const_eval::const_eval::dummy_machine::DummyMachine>>::eval_mir_constant
   7: <rustc_mir_transform::known_panics_lint::ConstPropagator>::eval_constant
   8: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_const_operand
   9: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_assign
  10: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_statement
  11: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_basic_block_data
  12: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_body
  13: <rustc_mir_transform::known_panics_lint::KnownPanicsLint as rustc_mir_transform::pass_manager::MirLint>::run_lint
  14: rustc_mir_transform::pass_manager::run_passes_inner
  15: rustc_mir_transform::run_analysis_to_runtime_passes
  16: rustc_mir_transform::mir_drops_elaborated_and_const_checked
      [... omitted 2 frames ...]
  17: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}
  18: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_span::def_id::LocalDefId, [rustc_span::def_id::LocalDefId], <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}>
  19: <rustc_session::session::Session>::time::<(), rustc_interface::passes::run_required_analyses::{closure#2}>
  20: rustc_interface::passes::analysis
      [... omitted 2 frames ...]
  21: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  22: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}>
  23: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>
  24: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
  25: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: rustc 1.102.0-nightly (d170e707b 2026-11-07) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=0

query stack during panic:
#0 [valtree_to_const_val] converting type-level constant value to MIR constant value
#1 [mir_drops_elaborated_and_const_checked] elaborating drops for `main`
#2 [analysis] running analysis passes on crate `huge_enum`
---
---- [ui] tests/ui/limits/huge-enum.rs#full-debuginfo stdout ----

error in revision `full-debuginfo`: Error: expected failure status (Some(1)) but received status Some(101).
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/limits/huge-enum.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--cfg" "full_debuginfo" "--check-cfg" "cfg(test,FALSE,no_debuginfo,full_debuginfo)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/limits/huge-enum.full-debuginfo" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2015" "-Cdebuginfo=2"
stdout: none
--- stderr -------------------------------

thread 'rustc' (91805) panicked at compiler/rustc_const_eval/src/const_eval/valtrees.rs:329:74:
called `Result::unwrap()` on an `Err` value: SizeOverflow(std::option::Option<[u32; 576460752303423487_usize]>)
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed::unwrap_failed_inner
   3: core::result::unwrap_failed::<&rustc_middle::ty::layout::LayoutError>
   4: rustc_const_eval::const_eval::valtrees::valtree_to_const_value
   5: <rustc_const_eval::provide::{closure#1} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_middle::ty::consts::valtree::Value)>>::call_once
      [... omitted 2 frames ...]
   6: <rustc_const_eval::interpret::eval_context::InterpCx<rustc_const_eval::const_eval::dummy_machine::DummyMachine>>::eval_mir_constant
   7: <rustc_mir_transform::known_panics_lint::ConstPropagator>::eval_constant
   8: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_const_operand
   9: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_assign
  10: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_statement
  11: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_basic_block_data
  12: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_body
  13: <rustc_mir_transform::known_panics_lint::KnownPanicsLint as rustc_mir_transform::pass_manager::MirLint>::run_lint
  14: rustc_mir_transform::pass_manager::run_passes_inner
  15: rustc_mir_transform::run_analysis_to_runtime_passes
  16: rustc_mir_transform::mir_drops_elaborated_and_const_checked
      [... omitted 2 frames ...]
  17: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}
  18: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_span::def_id::LocalDefId, [rustc_span::def_id::LocalDefId], <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}>
  19: <rustc_session::session::Session>::time::<(), rustc_interface::passes::run_required_analyses::{closure#2}>
  20: rustc_interface::passes::analysis
      [... omitted 2 frames ...]
  21: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  22: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}>
  23: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>
  24: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
  25: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: rustc 1.102.0-nightly (d170e707b 2026-11-07) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=2

query stack during panic:
#0 [valtree_to_const_val] converting type-level constant value to MIR constant value
#1 [mir_drops_elaborated_and_const_checked] elaborating drops for `main`
#2 [analysis] running analysis passes on crate `huge_enum`
---
---- [ui] tests/ui/limits/huge-struct.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit status: 101
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/limits/huge-struct.rs" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/limits/huge-struct" "-Znext-solver=coherence" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2015"
stdout: none
--- stderr -------------------------------

thread 'rustc' (91854) panicked at compiler/rustc_const_eval/src/const_eval/valtrees.rs:329:74:
called `Result::unwrap()` on an `Err` value: SizeOverflow(S32<S32<S1k<S1M<S1M<u32>>>>>)
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed::unwrap_failed_inner
   3: core::result::unwrap_failed::<&rustc_middle::ty::layout::LayoutError>
   4: rustc_const_eval::const_eval::valtrees::valtree_to_const_value
   5: <rustc_const_eval::provide::{closure#1} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_middle::ty::consts::valtree::Value)>>::call_once
      [... omitted 2 frames ...]
   6: <rustc_const_eval::interpret::eval_context::InterpCx<rustc_const_eval::const_eval::dummy_machine::DummyMachine>>::eval_mir_constant
   7: <rustc_mir_transform::known_panics_lint::ConstPropagator>::eval_constant
   8: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_const_operand
   9: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_assign
  10: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_statement
  11: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_basic_block_data
  12: <rustc_mir_transform::known_panics_lint::ConstPropagator as rustc_middle::mir::visit::Visitor>::visit_body
  13: <rustc_mir_transform::known_panics_lint::KnownPanicsLint as rustc_mir_transform::pass_manager::MirLint>::run_lint
  14: rustc_mir_transform::pass_manager::run_passes_inner
  15: rustc_mir_transform::run_analysis_to_runtime_passes
  16: rustc_mir_transform::mir_drops_elaborated_and_const_checked
      [... omitted 2 frames ...]
  17: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}
  18: rustc_data_structures::sync::parallel::par_for_each_in::<rustc_span::def_id::LocalDefId, [rustc_span::def_id::LocalDefId], <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners<rustc_interface::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}>
  19: <rustc_session::session::Session>::time::<(), rustc_interface::passes::run_required_analyses::{closure#2}>
  20: rustc_interface::passes::analysis
      [... omitted 2 frames ...]
  21: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  22: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>::{closure#2}>
  23: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::compiler_entrypoint::{closure#0}::{closure#1}>
  24: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
  25: rustc_span::create_session_globals_then::<(), rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::compiler_entrypoint::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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

note: rustc 1.102.0-nightly (d170e707b 2026-11-07) running on aarch64-unknown-linux-gnu

note: compiler flags: -Z simulate-remapped-rust-src-base=/rustc/FAKE_PREFIX -Z translate-remapped-path-to-local-path=no -Z ignore-directory-in-diagnostics-source-blocks=/cargo -Z ignore-directory-in-diagnostics-source-blocks=/checkout/vendor -C codegen-units=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z write-long-types-to-disk=no -C strip=debuginfo -C prefer-dynamic -Z next-solver=coherence -C rpath -C debuginfo=0

query stack during panic:
#0 [valtree_to_const_val] converting type-level constant value to MIR constant value
#1 [mir_drops_elaborated_and_const_checked] elaborating drops for `main`
#2 [analysis] running analysis passes on crate `huge_struct`

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A-array Area: `[T; N]` S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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Successfully merging this pull request may close these issues.

Array repeat exprs dont permit non-copy adt ctors as elements Constants in array repeat expression feature doesn't work with unit structs

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@Jules-Bertholet @rust-log-analyzer @rustbot