Stabilize is_partitioned

[TheWastl]

Closes #62544

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[rust-log-analyzer]

The job x86_64-gnu-llvm-9 of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[command]/usr/bin/git submodule foreach --recursive git config --local --name-only --get-regexp 'http\.https\:\/\/github\.com\/\.extraheader' && git config --local --unset-all 'http.https://github.com/.extraheader' || :
[command]/usr/bin/git config --local http.https://github.com/.extraheader AUTHORIZATION: basic ***
##[endgroup]
##[group]Fetching the repository
[command]/usr/bin/git -c protocol.version=2 fetch --no-tags --prune --progress --no-recurse-submodules --depth=2 origin +73d05dfcf8c2036697eacb0514a57f49bb3c1491:refs/remotes/pull/80085/merge
---
   Compiling libc v0.2.79
   Compiling std v0.0.0 (/checkout/library/std)
   Compiling compiler_builtins v0.1.36
   Compiling unwind v0.0.0 (/checkout/library/unwind)
error[E0541]: unknown meta item 'since'
     |
     |
1808 |     #[unstable(feature = "iter_is_partitioned", since = "1.49.0")]
     |                                                 ^^^^^^^^^^^^^^^^ expected one of `feature`, `reason`, `issue`, `soft`
error: aborting due to previous error

For more information about this error, try `rustc --explain E0541`.
error: could not compile `core`

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

[rust-log-analyzer]

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[command]/usr/bin/git submodule foreach --recursive git config --local --name-only --get-regexp 'http\.https\:\/\/github\.com\/\.extraheader' && git config --local --unset-all 'http.https://github.com/.extraheader' || :
[command]/usr/bin/git config --local http.https://github.com/.extraheader AUTHORIZATION: basic ***
##[endgroup]
##[group]Fetching the repository
[command]/usr/bin/git -c protocol.version=2 fetch --no-tags --prune --progress --no-recurse-submodules --depth=2 origin +ea3c925217c562b5bbfc5911172edc93a1bfbaed:refs/remotes/pull/80085/merge
---
    Checking rustc_ast_lowering v0.0.0 (/checkout/compiler/rustc_ast_lowering)
    Checking chalk-engine v0.36.0
    Checking rustc_middle v0.0.0 (/checkout/compiler/rustc_middle)
    Checking rustc_ast_passes v0.0.0 (/checkout/compiler/rustc_ast_passes)
error: the feature `iter_is_partitioned` has been stable since 1.49.0 and no longer requires an attribute to enable
  |
8 | #![feature(iter_is_partitioned)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  |
  = note: `-D stable-features` implied by `-D warnings`
error: aborting due to previous error

error: could not compile `rustc_ast_passes`


To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed
command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "check" "--target" "x86_64-unknown-linux-gnu" "-Zbinary-dep-depinfo" "-j" "16" "--release" "--color" "always" "--features" " llvm max_level_info" "--manifest-path" "/checkout/compiler/rustc/Cargo.toml" "-p" "rustc-main" "-p" "rustc_codegen_ssa" "-p" "rustc_incremental" "-p" "rustc_graphviz" "-p" "rustc_target" "-p" "rustc_errors" "-p" "rustc_lint_defs" "-p" "rustc_data_structures" "-p" "rustc_macros" "-p" "rustc_symbol_mangling" "-p" "rustc_fs_util" "-p" "rustc_middle" "-p" "rustc_type_ir" "-p" "rustc_arena" "-p" "rustc_feature" "-p" "rustc_query_system" "-p" "rustc_index" "-p" "rustc_apfloat" "-p" "rustc_hir" "-p" "rustc_attr" "-p" "rustc_ast_pretty" "-p" "rustc_lexer" "-p" "rustc_span" "-p" "rustc_ast" "-p" "rustc_serialize" "-p" "rustc_session" "-p" "rustc_driver" "-p" "rustc_save_analysis" "-p" "rustc_metadata" "-p" "rustc_expand" "-p" "rustc_ast_passes" "-p" "rustc_plugin_impl" "-p" "rustc_error_codes" "-p" "rustc_lint" "-p" "rustc_parse_format" "-p" "rustc_trait_selection" "-p" "rustc_infer" "-p" "rustc_interface" "-p" "rustc_ty_utils" "-p" "rustc_typeck" "-p" "rustc_passes" "-p" "rustc_ast_lowering" "-p" "rustc_codegen_llvm" "-p" "rustc_llvm" "-p" "rustc_builtin_macros" "-p" "rustc_resolve" "-p" "rustc_mir_build" "-p" "rustc_traits" "-p" "rustc_privacy" "-p" "rustc_mir" "-p" "coverage_test_macros" "-p" "rustc_hir_pretty" "-p" "rustc_parse" "--message-format" "json-render-diagnostics"
failed to run: /checkout/obj/build/bootstrap/debug/bootstrap check
Build completed unsuccessfully in 0:02:42
== clock drift check ==
  local time: Wed Dec 16 18:29:10 UTC 2020

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

[m-ou-se]

1.49 is already in beta and 1.50 is going to be in beta soon, so this should probably be 1.51.

[TheWastl]

Changed

[m-ou-se]

@rfcbot merge

[rfcbot]

Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @KodrAus
• @dtolnay
• @m-ou-se
• @sfackler
• @withoutboats

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

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[BurntSushi]

I've looked at the various linked issues but didn't see any motivating use cases for this routine. cc @cuviper

[cuviper]

My own motivation was just that someone asked for partitioning like C++ <algorithm>, and it was easy enough to emulate std::is_partitioned at the same time. I don't personally need it though.

[TheWastl]

I don't personally need it either. My motivation for this PR was also someone else. They were wondering why it was not stabilized, as there had been no activity on the tracking issue for almost 1.5 years. I've told the person to comment here.

[m-ou-se]

Thinking a bit more about this, I suppose that pretty much all use cases of this function are also covered by is_sorted_by_key .

[m-ou-se]

I've added the unresolved questions to the tracking issue. Cancelling the FCP for now, as we first need to discuss/resolve those.

@rfcbot cancel

[rfcbot]

@m-ou-se proposal cancelled.

[m-ou-se]

Let's continue the discussion on the tracking issue. Thanks!