Rollup of 19 pull requests

[Centril]

Successful merges:

• Redo the docs for Vec::set_len #56425 (Redo the docs for Vec::set_len)
• Issue #56905 #56906 (Issue Add a map in the TypeckTables to get all Upvars given the a closure ID #56905)
• Don't call FieldPlacement::count when count is too large #57042 (Don't call FieldPlacement::count when count is too large)
• Change std::error::Error trait documentation to talk about source instead of cause #57192 (Change std::error::Error trait documentation to talk about source instead of cause)
• Fixed the link to the ? operator #57296 (Fixed the link to the ? operator)
• Optimise floating point is_finite (2x) and is_infinite (1.6x). #57353 (Optimise floating point is_finite (2x) and is_infinite (1.6x).)
• Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for ccache #57368 (Use CMAKE_{C,CXX}_COMPILER_LAUNCHER for ccache)
• Rustdoc: update Source Serif Pro and replace Heuristica italic #57400 (Rustdoc: update Source Serif Pro and replace Heuristica italic)
• Improve the wording #57412 (Improve the wording)
• rustdoc: use text-based doctest parsing if a macro is wrapping main #57417 (rustdoc: use text-based doctest parsing if a macro is wrapping main)
• Add link destination for read-ownership #57433 (Add link destination for read-ownership)
• Remove CrateNum::Invalid. #57434 (Remove CrateNum::Invalid.)
• Supporting backtrace for x86_64-fortanix-unknown-sgx. #57441 (Supporting backtrace for x86_64-fortanix-unknown-sgx.)
• actually take a slice in this example #57450 (actually take a slice in this example)
• Some cleanups for core::fmt #57454 (Some cleanups for core::fmt)
• Reference tracking issue for inherent associated types in diagnostic #57459 (Reference tracking issue for inherent associated types in diagnostic)
• docs: Fix some 'second-edition' links #57463 (docs: Fix some 'second-edition' links)
• Remove outdated comment #57466 (Remove outdated comment)
• use structured suggestion when casting a reference #57493 (use structured suggestion when casting a reference)

Failed merges:

r? @ghost

[Centril]

@bors r+ p=19

[bors]

📌 Commit 7c590fe6699fa546f08ae8ed6d689403db11fd42 has been approved by Centril

[bors]

⌛ Testing commit 7c590fe6699fa546f08ae8ed6d689403db11fd42 with merge 8d7aa49d2fc058a000d668024fe4fd65f81552fe...

[bors]

💔 Test failed - checks-travis

[rust-highfive]

The job x86_64-gnu-full-bootstrap of your PR failed on Travis (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.

[00:05:10] [RUSTC-TIMING] rustc_errors test:false 13.172
[00:06:14] [RUSTC-TIMING] syntax test:false 64.202
[00:06:14]    Compiling syntax_ext v0.0.0 (/checkout/src/libsyntax_ext)
[00:06:45] [RUSTC-TIMING] syntax_ext test:false 31.194
No output has been received in the last 30m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received
The build has been terminated

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 @TimNN. (Feature Requests)

[Centril]

Can't see any reason in any of the included PRs why this should time out, so...

@bors retry

[bors]

⌛ Testing commit 7c590fe6699fa546f08ae8ed6d689403db11fd42 with merge 35f174f84f5f4fdb413c1cad5d4266593575647f...