Rollup of 9 pull requests

[Manishearth]

• Successful merges: Auto-toolstate management follow-up. #48405, Remove E0245; improve E0404 #48446, Support parentheses in patterns under feature gate #48500, Fix find_width_of_character_at_span bounds check #48522, rustc: Tweak funclet cleanups of ffi functions #48572, Stabilize LocalKey::try_with #48585, Add regression test for #48551 #48610, Fix link to rustc guide in README.md #48626, Add AArch64 features to whitelist #48570
• Failed merges:

[rust-highfive]

r? @petrochenkov

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[Manishearth]

@bors r+ p=10

[bors]

📌 Commit bad6ac7 has been approved by Manishearth

[Manishearth]

I am not closing the tree or supervising this; thought I'd land a rollup overnight. If it fails it fails (feel free to fix it up, maintainers can push to this PR, or close it in favor of another).

I'm trying to do more, smaller, less riskier, rollups, over large ones.

[bors]

⌛ Testing commit bad6ac74cd00bf591c0e1376c7e3410961bb04f6 with merge b95f4f8a10d527e014995961983fddfc01f00900...

[bors]

💔 Test failed - status-travis

[kennytm]

@bors retry

3 hour timeout in asmjs.

1 hr 24 min spent on testing run-pass.

make-prepare                	  77.56
pytest/bootstrap            	   0.00
stage0-std                  	  86.93
stage0-test                 	  16.88
stage0-rustc                	1303.26
llvm                        	 374.77
stage0-trans-llvm           	 222.65
llvm-emscripten             	 178.92
stage0-trans-emscripten     	 101.89
stage1-std                  	 106.24
stage1-test                 	  24.38
stage1-rustc                	1925.45
stage1-trans-llvm           	 251.70
stage1-trans-emscripten     	 141.57
stage2-std                  	  79.94
stage2-test                 	  17.86
stage0-compiletest          	  65.40
test/ui                     	 286.97
test/run-pass               	5015.79
test/compile-fail           	 136.52
test/parse-fail             	   5.29

[kennytm]

@bors r+

Added the remaining two marked rollups #48432, #48570.

[bors]

📌 Commit ac933a7 has been approved by kennytm

[bors]

⌛ Testing commit ac933a7170c6758052558fe45667cfc32c602ff5 with merge fec78e6a7f0b80d07085c78d3143fb4ba991229e...

[bors]

💔 Test failed - status-travis

[Manishearth]

@bors r+

[bors]

📌 Commit 2b3c815 has been approved by Manishearth

[bors]

⌛ Testing commit 2b3c815 with merge 26233b3943edf4b1c83afc455bbe478beb4e1149...

[bors]

💔 Test failed - status-appveyor

[Manishearth]

@bors retry

[bors]

⌛ Testing commit 2b3c815 with merge beca3761acd2ce1548351c26607c217f6eec75c6...

[Manishearth]

SHIT forgot about the branches