Rollup of 5 pull requests

[Centril]

Successful merges:

• apfloat: improve doc comments #63416 (apfloat: improve doc comments)
• Add long error explanation for E0495 #64404 (Add long error explanation for E0495)
• syntax: cleanup param, method, and misc parsing #64910 (syntax: cleanup param, method, and misc parsing)
• Remove unneeded fn main blocks from docs #64912 (Remove unneeded fn main blocks from docs)
• Update cargo. #64952 (Update cargo.)

Failed merges:

r? @ghost

[Centril]

@bors r+ p=5 rollup=never

[bors]

📌 Commit 98344d7 has been approved by Centril

[bors]

⌛ Testing commit 98344d7 with merge 8d0ebb2...

[bors]

💔 Test failed - checks-azure

[rust-highfive]

The job x86_64-gnu-nopt 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.

2019-10-01T16:19:41.9786459Z 25 
2019-10-01T16:19:41.9786487Z 
2019-10-01T16:19:41.9786549Z 
2019-10-01T16:19:41.9786605Z The actual stderr differed from the expected stderr.
2019-10-01T16:19:41.9786948Z Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/in-band-lifetimes/mismatched_trait_impl.nll/mismatched_trait_impl.nll.stderr
2019-10-01T16:19:41.9787230Z To update references, rerun the tests and pass the `--bless` flag
2019-10-01T16:19:41.9787528Z To only update this specific test, also pass `--test-args in-band-lifetimes/mismatched_trait_impl.rs`
2019-10-01T16:19:41.9787669Z error: 1 errors occurred comparing output.
2019-10-01T16:19:41.9787730Z status: exit code: 1
2019-10-01T16:19:41.9787730Z status: exit code: 1
2019-10-01T16:19:41.9788530Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/in-band-lifetimes/mismatched_trait_impl.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/in-band-lifetimes/mismatched_trait_impl.nll" "-Zborrowck=mir" "-Crpath" "-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/in-band-lifetimes/mismatched_trait_impl.nll/auxiliary" "-A" "unused"
2019-10-01T16:19:41.9789000Z ------------------------------------------
2019-10-01T16:19:41.9789044Z 
2019-10-01T16:19:41.9789265Z ------------------------------------------
2019-10-01T16:19:41.9790042Z stderr:
2019-10-01T16:19:41.9790042Z stderr:
2019-10-01T16:19:41.9790402Z ------------------------------------------
2019-10-01T16:19:41.9790763Z error[E0495]: cannot infer an appropriate lifetime for lifetime parameter 'a in generic type due to conflicting requirements
2019-10-01T16:19:41.9791219Z    |
2019-10-01T16:19:41.9791219Z    |
2019-10-01T16:19:41.9791660Z LL |     fn foo(&self, x: &u32, y: &'a u32) -> &'a u32 { //~ ERROR cannot infer
2019-10-01T16:19:41.9791875Z    |
2019-10-01T16:19:41.9791875Z    |
2019-10-01T16:19:41.9791983Z note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the method body at 9:5...
2019-10-01T16:19:41.9792429Z    |
2019-10-01T16:19:41.9792429Z    |
2019-10-01T16:19:41.9792720Z LL | /     fn foo(&self, x: &u32, y: &'a u32) -> &'a u32 { //~ ERROR cannot infer
2019-10-01T16:19:41.9792837Z LL | |         x //~ ERROR lifetime mismatch
2019-10-01T16:19:41.9793155Z    | |_____^
2019-10-01T16:19:41.9793155Z    | |_____^
2019-10-01T16:19:41.9793608Z note: ...but the lifetime must also be valid for the lifetime 'a as defined on the method body at 9:32...
2019-10-01T16:19:41.9793937Z    |
2019-10-01T16:19:41.9793937Z    |
2019-10-01T16:19:41.9794164Z LL |     fn foo(&self, x: &u32, y: &'a u32) -> &'a u32 { //~ ERROR cannot infer
2019-10-01T16:19:41.9794336Z    = note: ...so that the method type is compatible with trait:
2019-10-01T16:19:41.9794336Z    = note: ...so that the method type is compatible with trait:
2019-10-01T16:19:41.9794555Z            expected fn(&i32, &'a u32, &u32) -> &'a u32
2019-10-01T16:19:41.9794792Z               found fn(&i32, &u32, &u32) -> &u32
2019-10-01T16:19:41.9795073Z error: aborting due to previous error
2019-10-01T16:19:41.9795111Z 
2019-10-01T16:19:41.9795330Z For more information about this error, try `rustc --explain E0495`.
2019-10-01T16:19:41.9795403Z 
---
2019-10-01T16:19:41.9830995Z thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:537:22
2019-10-01T16:19:41.9831166Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
2019-10-01T16:19:41.9847030Z 
2019-10-01T16:19:41.9847133Z 
2019-10-01T16:19:41.9850124Z 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" "/checkout/obj/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--host-rustcflags" "-Crpath -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -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" "--llvm-version" "9.0.0-rust-1.40.0-dev\n" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always" "--compare-mode" "nll"
2019-10-01T16:19:41.9851102Z 
2019-10-01T16:19:41.9851142Z 
2019-10-01T16:19:41.9855092Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
2019-10-01T16:19:41.9855207Z Build completed unsuccessfully in 1:51:47
2019-10-01T16:19:41.9855207Z Build completed unsuccessfully in 1:51:47
2019-10-01T16:19:41.9907008Z == clock drift check ==
2019-10-01T16:19:41.9926360Z   local time: Tue Oct  1 16:19:41 UTC 2019
2019-10-01T16:19:42.0637918Z   network time: Tue, 01 Oct 2019 16:19:42 GMT
2019-10-01T16:19:42.0638058Z == end clock drift check ==
2019-10-01T16:19:42.9266946Z ##[error]Bash exited with code '1'.
2019-10-01T16:19:42.9303548Z ##[section]Starting: Upload CPU usage statistics
2019-10-01T16:19:42.9309838Z ==============================================================================
2019-10-01T16:19:42.9309977Z Task         : Bash
2019-10-01T16:19:42.9310073Z Description  : Run a Bash script on macOS, Linux, or Windows

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