WIP: smart pointer (try_)map

[Qelxiros]

Tracking issue: #144419

[rust-log-analyzer]

The job aarch64-gnu-llvm-19-1 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/privacy/suggest-box-new.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/privacy/suggest-box-new.rs" "-Zthreads=1" "-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" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/privacy/suggest-box-new" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::collections::HashMap`
##[error]  --> /checkout/tests/ui/privacy/suggest-box-new.rs:14:13
   |
---
   |
LL -     let _ = std::collections::HashMap();
LL +     let _ = std::collections::HashMap::with_hasher(_);
   |
LL -     let _ = std::collections::HashMap();
LL +     let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
   |
help: consider using the `Default` trait
   |
LL |     let _ = <std::collections::HashMap as std::default::Default>::default();
   |             +                          ++++++++++++++++++++++++++++++++++

error[E0423]: cannot initialize a tuple struct which contains private fields
##[error]  --> /checkout/tests/ui/privacy/suggest-box-new.rs:8:19
   |
LL |         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
   |                   ^^^
   |
note: constructor is not visible here due to private fields
  --> /rustc/FAKE_PREFIX/library/alloc/src/boxed.rs:234:14
   |
   = note: private field
   |
   = note: private field
help: you might have meant to use an associated function to build this type
   |
LL -         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
LL -             wtf: None,
LL -             x: (),
LL -         })),
LL +         wtf: Some(Box::new(_)),
   |
LL -         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
LL -             wtf: None,
LL -             x: (),
LL -         })),
LL +         wtf: Some(Box::new_uninit()),
   |
LL -         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
LL -             wtf: None,
LL -             x: (),
LL -         })),
LL +         wtf: Some(Box::new_zeroed()),
   |
LL -         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
LL -             wtf: None,
LL -             x: (),
LL -         })),
LL +         wtf: Some(Box::new_in(_, _)),
   |
   = and 13 other candidates
help: consider using the `Default` trait
   |
LL -         wtf: Some(Box(U { //~ ERROR cannot initialize a tuple struct which contains private fields
LL +         wtf: Some(<Box as std::default::Default>::default()),
   |

error: cannot construct `HashMap<_, _, _>` with struct literal syntax due to private fields
##[error]  --> /checkout/tests/ui/privacy/suggest-box-new.rs:16:13
   |
---
   |
LL -     let _ = std::collections::HashMap {};
LL +     let _ = std::collections::HashMap::with_hasher(_);
   |
LL -     let _ = std::collections::HashMap {};
LL +     let _ = std::collections::HashMap::with_capacity_and_hasher(_, _);
   |
help: consider using the `Default` trait
   |
LL -     let _ = std::collections::HashMap {};
LL +     let _ = <std::collections::HashMap as std::default::Default>::default();

[rustbot]

r? @thomcc

rustbot has assigned @thomcc.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[Qelxiros]

As far as I can tell, the ICE here is because of the function signature of Box::try_map. The return type is equivalent to ChangeOutputType<...> from the ACP, but that definition is in core, so I implemented it manually here. However, when I add the same type alias to alloc, the ICE persists. Is there a workaround here that remains in the spirit of the ACP? Is this a known compiler bug?