Rollup of 6 pull requests

[RalfJung]

Successful merges:

• Don't type_of on trait assoc ty without default #72149 (Don't type_of on trait assoc ty without default)
• Make intra-link resolve links for both trait and impl items #72347 (Make intra-link resolve links for both trait and impl items)
• Improve documentation of slice::from_raw_parts #72350 (Improve documentation of slice::from_raw_parts)
• Show default values for debug-assertions & debug-assertions-std #72382 (Show default values for debug-assertions & debug-assertions-std)
• Fix anchor display when hovering impl #72421 (Fix anchor display when hovering impl)
• fix discriminant_value sign extension #72425 (fix discriminant_value sign extension)

Failed merges:

r? @ghost

[rust-highfive]

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-tools
##[section]Starting: Initialize job
Agent name: 'Azure Pipelines 2'
Agent machine name: 'fv-az578'
Current agent version: '2.168.2'
##[group]Operating System
16.04.6
LTS
LTS
##[endgroup]
##[group]Virtual Environment
Environment: ubuntu-16.04
Version: 20200512.2
Included Software: https://github.com/actions/virtual-environments/blob/ubuntu16/20200512.2/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 (3.163.2)
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/3ea6e7ac-8450-4748-944f-8e894ac4115b.sh

##[section]Finishing: Disable git automatic line ending conversion
##[section]Starting: Checkout rust-lang/rust@refs/pull/72432/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/72432/merge:refs/remotes/pull/72432/merge
fatal: couldn't find remote ref refs/pull/72432/merge
##[warning]Git fetch failed with exit code 128, back off 5.54 seconds before retry.
##[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/72432/merge:refs/remotes/pull/72432/merge
fatal: couldn't find remote ref refs/pull/72432/merge
##[warning]Git fetch failed with exit code 128, back off 8.508 seconds before retry.
##[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/72432/merge:refs/remotes/pull/72432/merge
fatal: couldn't find remote ref refs/pull/72432/merge
##[error]Git fetch failed with exit code: 128
##[section]Finishing: Checkout rust-lang/rust@refs/pull/72432/merge to s
##[section]Starting: Checkout rust-lang/rust@refs/pull/72432/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)
==============================================================================
##[section]Finishing: Checkout rust-lang/rust@refs/pull/72432/merge to s
Cleaning up task key
Start cleaning up orphan processes.
##[section]Finishing: Finalize Job
##[section]Finishing: Linux x86_64-gnu-tools

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