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Make likely and unlikely const, gated by feature const_unlikely #73778

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merged 4 commits into from
Jul 1, 2020

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nbdd0121
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This PR also contains a fix to allow #[allow_internal_unstable] to work properly with #[rustc_const_unstable].

cc @RalfJung @nagisa

r? @oli-obk

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 26, 2020
@Mark-Simulacrum Mark-Simulacrum added S-waiting-on-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). T-lang Relevant to the language team, which will review and decide on the PR/issue. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. S-waiting-on-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). labels Jun 26, 2020
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The job x86_64-gnu-llvm-8 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.
##[section]Starting: Linux x86_64-gnu-llvm-8
##[section]Starting: Initialize job
Agent name: 'Azure Pipelines 6'
Agent machine name: 'fv-az578'
Current agent version: '2.171.1'
##[group]Operating System
16.04.6
LTS
LTS
##[endgroup]
##[group]Virtual Environment
Environment: ubuntu-16.04
Version: 20200621.1
Included Software: https://github.com/actions/virtual-environments/blob/ubuntu16/20200621.1/images/linux/Ubuntu1604-README.md
##[endgroup]
Agent running as: 'vsts'
Prepare build directory.
Set build variables.
Download all required tasks.
Download all required tasks.
Downloading task: Bash (3.171.1)
Checking job knob settings.
   Knob: AgentToolsDirectory = /opt/hostedtoolcache Source: ${AGENT_TOOLSDIRECTORY} 
   Knob: AgentPerflog = /home/vsts/perflog Source: ${VSTS_AGENT_PERFLOG} 
Start tracking orphan processes.
##[section]Finishing: Initialize job
##[section]Starting: Configure Job Name
==============================================================================
---
========================== Starting Command Output ===========================
[command]/bin/bash --noprofile --norc /home/vsts/work/_temp/8e8da4f1-de2a-42b1-8834-1547c9f9f676.sh

##[section]Finishing: Disable git automatic line ending conversion
##[section]Starting: Checkout rust-lang/rust@refs/pull/73778/merge to s
Task         : Get sources
Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
Version      : 1.0.0
Author       : Microsoft
---
##[command]git remote add origin https://github.com/rust-lang/rust
##[command]git config gc.auto 0
##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
##[command]git config --get-all http.proxy
##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/73778/merge:refs/remotes/pull/73778/merge
---
 ---> 31fea614d2f3
Step 5/8 : ENV RUST_CONFIGURE_ARGS       --build=x86_64-unknown-linux-gnu       --llvm-root=/usr/lib/llvm-8       --enable-llvm-link-shared       --set rust.thin-lto-import-instr-limit=10
 ---> Using cache
 ---> 4195cadf126d
Step 6/8 : ENV SCRIPT python2.7 ../x.py test --exclude src/tools/tidy &&            python2.7 ../x.py test src/test/mir-opt --pass=build                                   --target=armv5te-unknown-linux-gnueabi &&            python2.7 ../x.py test src/tools/tidy
 ---> 4e90f6b48f05
Step 7/8 : ENV NO_DEBUG_ASSERTIONS=1
 ---> Using cache
 ---> dfa0a356d899
---
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model  : 85
model name : Intel(R) Xeon(R) Platinum 8272CL CPU @ 2.60GHz
microcode : 0xffffffff
cpu MHz  : 2593.907
cache size : 36608 KB
physical id : 0
---
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model  : 85
model name : Intel(R) Xeon(R) Platinum 8272CL CPU @ 2.60GHz
microcode : 0xffffffff
cpu MHz  : 2593.907
cache size : 36608 KB
physical id : 0
---
Set({"src/librustc_parse_format"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_passes"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_plugin_impl"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_privacy"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_query_system"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_save_analysis"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_serialize"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_session"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_span"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
---
Set({"src/librustc_parse_format"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_passes"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_plugin_impl"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_privacy"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_query_system"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_save_analysis"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_serialize"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_session"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_span"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
---
   Compiling rustc_parse_format v0.0.0 (/checkout/src/librustc_parse_format)
   Compiling tracing v0.1.15
   Compiling rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
   Compiling rustc_hir v0.0.0 (/checkout/src/librustc_hir)
   Compiling rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
   Compiling chalk-engine v0.14.0
   Compiling rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
   Compiling rustc_parse v0.0.0 (/checkout/src/librustc_parse)
   Compiling rustc_ast_lowering v0.0.0 (/checkout/src/librustc_ast_lowering)
---
   Compiling rustc_parse_format v0.0.0 (/checkout/src/librustc_parse_format)
   Compiling tracing v0.1.15
   Compiling rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
   Compiling rustc_hir v0.0.0 (/checkout/src/librustc_hir)
   Compiling rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
   Compiling chalk-engine v0.14.0
   Compiling rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
   Compiling chalk-solve v0.14.0
   Compiling rustc_parse v0.0.0 (/checkout/src/librustc_parse)
---
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---
failures:

---- [ui] ui/consts/const-eval/dont_promote_unstable_const_fn.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/const-eval/dont_promote_unstable_const_fn.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/const-eval/dont_promote_unstable_const_fn" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/const-eval/dont_promote_unstable_const_fn/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/const-typeid-of.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/const-typeid-of.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/const-typeid-of" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/const-typeid-of/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`const_type_id` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/min_const_fn/min_const_fn_libstd_stability.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_fn_libstd_stability" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_fn_libstd_stability/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/miri_unleashed/abi-mismatch.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/miri_unleashed/abi-mismatch.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/miri_unleashed/abi-mismatch" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Z" "unleash-the-miri-inside-of-you" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/miri_unleashed/abi-mismatch/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`const_transmute` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -Z unleash-the-miri-inside-of-you -C prefer-dynamic -C rpath -C debuginfo=0
warning: skipping const checks
   |
help: skipping check that does not even have a feature gate
  --> /checkout/src/test/ui/consts/miri_unleashed/abi-mismatch.rs:10:5
  --> /checkout/src/test/ui/consts/miri_unleashed/abi-mismatch.rs:10:5
   |
LL |     my_fn();

warning: 1 warning emitted



------------------------------------------


---- [ui] ui/consts/miri_unleashed/ptr_arith.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/miri_unleashed/ptr_arith.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/miri_unleashed/ptr_arith" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Zunleash-the-miri-inside-of-you" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/miri_unleashed/ptr_arith/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`const_transmute` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -Z unleash-the-miri-inside-of-you -C prefer-dynamic -C rpath -C debuginfo=0
warning: skipping const checks
   |
help: skipping check that does not even have a feature gate
  --> /checkout/src/test/ui/consts/miri_unleashed/ptr_arith.rs:9:14
  --> /checkout/src/test/ui/consts/miri_unleashed/ptr_arith.rs:9:14
   |
LL |     let _v = x == x;

warning: 1 warning emitted



------------------------------------------


---- [ui] ui/feature-gates/feature-gate-const_transmute.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/feature-gates/feature-gate-const_transmute.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gates/feature-gate-const_transmute" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/feature-gates/feature-gate-const_transmute/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`const_transmute` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (ad5cb0b3a 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------


---
thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:344:22
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-8/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "8.0.0" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --exclude src/tools/tidy
Build completed unsuccessfully in 0:54:40
Build completed unsuccessfully in 0:54:40
== clock drift check ==
  local time: Fri Jun 26 21:39:47 UTC 2020
  network time: Fri, 26 Jun 2020 21:39:47 GMT
== end clock drift check ==

##[error]Bash exited with code '1'.
##[section]Finishing: Run build
##[section]Starting: Checkout rust-lang/rust@refs/pull/73778/merge to s
Task         : Get sources
Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
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Author       : Microsoft
Author       : Microsoft
Help         : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
==============================================================================
Cleaning any cached credential from repository: rust-lang/rust (GitHub)
##[section]Finishing: Checkout rust-lang/rust@refs/pull/73778/merge to s
Cleaning up task key
Start cleaning up orphan processes.
Terminate orphan process: pid (3816) (python)
##[section]Finishing: Finalize Job

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The job x86_64-gnu-llvm-8 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.
##[section]Starting: Linux x86_64-gnu-llvm-8
##[section]Starting: Initialize job
Agent name: 'Azure Pipelines 4'
Agent machine name: 'fv-az578'
Current agent version: '2.171.1'
##[group]Operating System
16.04.6
LTS
LTS
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##[group]Virtual Environment
Environment: ubuntu-16.04
Version: 20200621.1
Included Software: https://github.com/actions/virtual-environments/blob/ubuntu16/20200621.1/images/linux/Ubuntu1604-README.md
##[endgroup]
Agent running as: 'vsts'
Prepare build directory.
Set build variables.
Download all required tasks.
Download all required tasks.
Downloading task: Bash (3.171.1)
Checking job knob settings.
   Knob: AgentToolsDirectory = /opt/hostedtoolcache Source: ${AGENT_TOOLSDIRECTORY} 
   Knob: AgentPerflog = /home/vsts/perflog Source: ${VSTS_AGENT_PERFLOG} 
Start tracking orphan processes.
##[section]Finishing: Initialize job
##[section]Starting: Configure Job Name
==============================================================================
---
========================== Starting Command Output ===========================
[command]/bin/bash --noprofile --norc /home/vsts/work/_temp/27b4dd29-c138-4ea6-910e-c102cfb847b8.sh

##[section]Finishing: Disable git automatic line ending conversion
##[section]Starting: Checkout rust-lang/rust@refs/pull/73778/merge to s
Task         : Get sources
Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
Version      : 1.0.0
Author       : Microsoft
---
##[command]git remote add origin https://github.com/rust-lang/rust
##[command]git config gc.auto 0
##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
##[command]git config --get-all http.proxy
##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/73778/merge:refs/remotes/pull/73778/merge
---
 ---> 31fea614d2f3
Step 5/8 : ENV RUST_CONFIGURE_ARGS       --build=x86_64-unknown-linux-gnu       --llvm-root=/usr/lib/llvm-8       --enable-llvm-link-shared       --set rust.thin-lto-import-instr-limit=10
 ---> Using cache
 ---> 4195cadf126d
Step 6/8 : ENV SCRIPT python2.7 ../x.py test --exclude src/tools/tidy &&            python2.7 ../x.py test src/test/mir-opt --pass=build                                   --target=armv5te-unknown-linux-gnueabi &&            python2.7 ../x.py test src/tools/tidy
 ---> 4e90f6b48f05
Step 7/8 : ENV NO_DEBUG_ASSERTIONS=1
 ---> Using cache
 ---> dfa0a356d899
---
Set({"src/librustc_parse_format"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_passes"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_plugin_impl"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_privacy"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_query_system"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_save_analysis"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_serialize"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_session"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_span"}) not skipped for "bootstrap::test::CrateLibrustc" -- not in ["src/tools/tidy"]
---
Set({"src/librustc_parse_format"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_passes"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_plugin_impl"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_privacy"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_query_system"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_save_analysis"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_serialize"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_session"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
Set({"src/librustc_span"}) not skipped for "bootstrap::doc::Rustc" -- not in ["src/tools/tidy"]
---
   Compiling rustc_parse_format v0.0.0 (/checkout/src/librustc_parse_format)
   Compiling tracing v0.1.15
   Compiling rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
   Compiling rustc_hir v0.0.0 (/checkout/src/librustc_hir)
   Compiling rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
   Compiling chalk-engine v0.14.0
   Compiling rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
   Compiling rustc_parse v0.0.0 (/checkout/src/librustc_parse)
   Compiling rustc_ast_lowering v0.0.0 (/checkout/src/librustc_ast_lowering)
---
   Compiling rustc_parse_format v0.0.0 (/checkout/src/librustc_parse_format)
   Compiling tracing v0.1.15
   Compiling rustc_ast_pretty v0.0.0 (/checkout/src/librustc_ast_pretty)
   Compiling rustc_hir v0.0.0 (/checkout/src/librustc_hir)
   Compiling rustc_query_system v0.0.0 (/checkout/src/librustc_query_system)
   Compiling chalk-engine v0.14.0
   Compiling rustc_hir_pretty v0.0.0 (/checkout/src/librustc_hir_pretty)
   Compiling chalk-solve v0.14.0
   Compiling rustc_parse v0.0.0 (/checkout/src/librustc_parse)
---
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---
failures:

---- [ui] ui/consts/min_const_fn/min_const_fn_libstd_stability.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_fn_libstd_stability" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_fn_libstd_stability/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (5fcddcfed 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (5fcddcfed 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------



---- [ui] ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.rs stdout ----

error: Error: expected failure status (Some(1)) but received status Some(101).
status: exit code: 101
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
thread 'rustc' panicked at '`foo` was not listed in `declare_features`', src/librustc_feature/active.rs:95:1

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.
note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: ***/blob/master/CONTRIBUTING.md#bug-reports
note: rustc 1.46.0-nightly (5fcddcfed 2020-06-26) running on x86_64-unknown-linux-gnu


note: compiler flags: -Z threads=1 -Z ui-testing -Z deduplicate-diagnostics=no -Z unstable-options -C prefer-dynamic -C rpath -C debuginfo=0

------------------------------------------


---
+   --> $DIR/feature-gate.rs:12:26
3    |
- LL | fn main() {}
-    | ^^^^^^^^^^^^
+ LL | const fn get_assoc_const<S: ?const T>() -> i32 { <S as T>::CONST }
+    |
+    |
+    = note: see issue #57563 <***/issues/57563> for more information
+    = help: add `#![feature(const_fn)]` to the crate attributes to enable
7 error: aborting due to previous error
8 

+ For more information about this error, try `rustc --explain E0723`.
+ For more information about this error, try `rustc --explain E0723`.
9 


The actual stderr differed from the expected stderr.
Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.gated/feature-gate.gated.stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.rs`

error in revision `gated`: 1 errors occurred comparing output.
status: exit code: 1
command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--cfg" "gated" "--error-format" "json" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.gated" "-A" "unused" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.gated/auxiliary"
------------------------------------------

------------------------------------------
stderr:
stderr:
------------------------------------------
error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable
  --> /checkout/src/test/ui/rfc-2632-const-trait-impl/const-trait-bound-opt-out/feature-gate.rs:12:26
   |
LL | const fn get_assoc_const<S: ?const T>() -> i32 { <S as T>::CONST }
   |
   |
   = note: see issue #57563 <***/issues/57563> for more information
   = help: add `#![feature(const_fn)]` to the crate attributes to enable
error: aborting due to previous error

For more information about this error, try `rustc --explain E0723`.

---
thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:344:22
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-8/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "8.0.0" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --exclude src/tools/tidy
Build completed unsuccessfully in 1:09:38
Build completed unsuccessfully in 1:09:38
== clock drift check ==
  local time: Fri Jun 26 23:49:42 UTC 2020
  network time: Fri, 26 Jun 2020 23:49:42 GMT
== end clock drift check ==

##[error]Bash exited with code '1'.
##[section]Finishing: Run build
##[section]Starting: Checkout rust-lang/rust@refs/pull/73778/merge to s
Task         : Get sources
Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.
Version      : 1.0.0
Author       : Microsoft
Author       : Microsoft
Help         : [More Information](https://go.microsoft.com/fwlink/?LinkId=798199)
==============================================================================
Cleaning any cached credential from repository: rust-lang/rust (GitHub)
##[section]Finishing: Checkout rust-lang/rust@refs/pull/73778/merge to s
Cleaning up task key
Start cleaning up orphan processes.
Terminate orphan process: pid (3988) (python)
##[section]Finishing: Finalize Job

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@oli-obk
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oli-obk commented Jun 27, 2020

lgtm. I'll add it to the const eval skill tree.

@rust-lang/lang This PR does two things:

  1. A trivial change making the likely and unlikely intrinsics unstably const fn. This means only unstable const fns can invoke these intrinsics. Since there's no way for a stable const fn to invoke an unstable const fn, that would be an invisible change. Additionally, even if we stabilized the constness of these intrinsics, they are only performance relevant, so we can destabilize them and take performance hits if we ever wanted to (I don't know why, these intrinsics are completely benign from a const eval perspective, they are nops).
  2. Allow stable const fn in the libstd to invoke unstable const fn iff the stable const fn has an allow_internal_unstable(the_const_feature_gate_of_the_unstable_const_fn) attribute. See https://github.com/rust-lang/rustc-dev-guide/blob/master/src/stability.md#allow_internal_unstable for documentation on the use of allow_internal_unstable on const fn.

The motivation for this change is to allow the checked_neg function to compile to assembly preferring the happy path.

rust/src/libcore/num/mod.rs

Lines 1867 to 1877 in 394e1b4

#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
#[allow(unused_attributes)]
#[allow_internal_unstable(const_if_match)]
pub const fn overflowing_neg(self) -> (Self, bool) {
if self == Self::MIN {
(Self::MIN, true)
} else {
(-self, false)
}
}

checked_neg is the only const-stable checked_* function, because it used to be implemented by math trickery instead of an if/else expression. We moved to an if/else expression allowing const_if_match via allow_internal_unstable, because we could always move back to the math trickery if there would be any problems. In order to keep it stable and using if/else, we need to allow the use of the unlikely intrinsic within this const-stable function. This is the first time we've permitted calling a const-unstable intrinsic from a const-stabale function, thus the request for your sign-off on the new capabilities of allow_internal_unstable.

Alternatively we can insta-stabilize the const-stability of the likely and unlikely intrinsics, but there is a general desire for such allow_internal_unstable capabilities.

@RalfJung
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Please remember to remove the intrinsic implementation from Miri once this one lands.

@nagisa
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nagisa commented Jun 27, 2020

The motivation for this change is to allow the checked_neg function to compile to assembly preferring the happy path.

Note, the linked issue is about checked_div, not neg.

@nbdd0121
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@oli-obk Note that this PR does not fix #69399, because

pub fn lib_feature_allowed(tcx: TyCtxt<'tcx>, def_id: DefId, feature_gate: Symbol) -> bool {
// All features require that the corresponding gate be enabled,
// even if the function has `#[allow_internal_unstable(the_gate)]`.
if !tcx.features().declared_lib_features.iter().any(|&(sym, _)| sym == feature_gate) {
return false;
}

which is copied from
fn feature_allowed(tcx: TyCtxt<'tcx>, def_id: DefId, feature_gate: Symbol) -> bool {
// All features require that the corresponding gate be enabled,
// even if the function has `#[allow_internal_unstable(the_gate)]`.
if !tcx.features().enabled(feature_gate) {
return false;
}

initially introduced in #68114.

This is different from the behaviour of #[allow_internal_unstable] behaviour when applied to macros today, which does not require the feature to be enabled on crate level. Is there a reason for the restriction @ecstatic-morse ?

@ecstatic-morse
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What's the question exactly? I'm not sure what you want to change.

@nbdd0121
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@ecstatic-morse #[allow_internal_unstable] requires the feature gate to be enabled on the crate when applied to functions. I just want to know the reason behind this restriction because you introduced it, and ideally have the restriction removed because this the restriction does not apply when #[allow_internal_unstable] is used on macro_rules!.

@ecstatic-morse
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I believe this was just the way it worked before, although this was broken for a while. Whats the problem with adding your library feature gate to libcore?

@nbdd0121
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I believe this was just the way it worked before, although this was broken for a while. Whats the problem with adding your library feature gate to libcore?

It's not an issue for me, but it is blocking #69399. And it is just weird that the same attribute has different restrictions when applied to function/macro respectively.

@ecstatic-morse
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I don't think the current behavior is weird. Writing a macro definition is not the same as writing a function. I also don't care very much.

@nikomatsakis
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I'm nominating for the @rust-lang/lang meeting today but I don't see a problem with having these functions available in const fn, presuming that we have them. They clearly have no semantic effect. This is only to make them available on an unstable basis so I think no FCP ought to be required.

@scottmcm
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I agree that unstable things generally don't need a lang FCP, especially for intrinsics that are by nature internal and more about compiler/libs-impl concerns than about the conceptual language itself.

@nikomatsakis
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Discussed this PR and gave approval in @rust-lang/lang meeting today.

@oli-obk
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oli-obk commented Jun 30, 2020

@bors r+

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bors commented Jun 30, 2020

📌 Commit 8b43012 has been approved by oli-obk

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 30, 2020
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this pull request Jun 30, 2020
Make `likely` and `unlikely` const, gated by feature `const_unlikely`

This PR also contains a fix to allow `#[allow_internal_unstable]` to work properly with `#[rustc_const_unstable]`.

cc @RalfJung @nagisa

r? @oli-obk
Manishearth added a commit to Manishearth/rust that referenced this pull request Jul 1, 2020
Make `likely` and `unlikely` const, gated by feature `const_unlikely`

This PR also contains a fix to allow `#[allow_internal_unstable]` to work properly with `#[rustc_const_unstable]`.

cc @RalfJung @nagisa

r? @oli-obk
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this pull request Jul 1, 2020
Make `likely` and `unlikely` const, gated by feature `const_unlikely`

This PR also contains a fix to allow `#[allow_internal_unstable]` to work properly with `#[rustc_const_unstable]`.

cc @RalfJung @nagisa

r? @oli-obk
bors added a commit to rust-lang-ci/rust that referenced this pull request Jul 1, 2020
…arth

Rollup of 17 pull requests

Successful merges:

 - rust-lang#72071 (Added detailed error code explanation for issue E0687 in Rust compiler.)
 - rust-lang#72369 (Bring net/parser.rs up to modern up to date with modern rust patterns)
 - rust-lang#72445 (Stabilize `#[track_caller]`.)
 - rust-lang#73466 (impl From<char> for String)
 - rust-lang#73548 (remove rustdoc warnings)
 - rust-lang#73649 (Fix sentence structure)
 - rust-lang#73678 (Update Box::from_raw example to generalize better)
 - rust-lang#73705 (stop taking references in Relate)
 - rust-lang#73716 (Document the static keyword)
 - rust-lang#73752 (Remap Windows ERROR_INVALID_PARAMETER to ErrorKind::InvalidInput from Other)
 - rust-lang#73776 (Move terminator to new module)
 - rust-lang#73778 (Make `likely` and `unlikely` const, gated by feature `const_unlikely`)
 - rust-lang#73805 (Document the type keyword)
 - rust-lang#73806 (Use an 'approximate' universal upper bound when reporting region errors)
 - rust-lang#73828 (Fix wording for anonymous parameter name help)
 - rust-lang#73846 (Fix comma in debug_assert! docs)
 - rust-lang#73847 (Edit cursor.prev() method docs in lexer)

Failed merges:

r? @ghost
@bors bors merged commit ec41d01 into rust-lang:master Jul 1, 2020
bors added a commit to rust-lang/miri that referenced this pull request Jul 3, 2020
Remove likely and unlikely from intrinsics shim

They are now implemented in MIR interpreter by rust-lang/rust#73778
@nbdd0121 nbdd0121 deleted the const_likely branch September 4, 2021 02:54
@cuviper cuviper added this to the 1.46 milestone May 2, 2024
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