Fixes #64919. Suggest fix based on operator precendence.

[sam09]

Fixes #64919

[rust-highfive]

r? @cramertj

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[sam09]

r? @varkor

[rust-highfive]

The job x86_64-gnu-llvm-6.0 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.

2019-09-30T23:11:49.3295548Z ##[command]git remote add origin https://github.com/rust-lang/rust
2019-09-30T23:11:49.3468197Z ##[command]git config gc.auto 0
2019-09-30T23:11:49.3549657Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2019-09-30T23:11:49.3605905Z ##[command]git config --get-all http.proxy
2019-09-30T23:11:49.3747692Z ##[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/64933/merge:refs/remotes/pull/64933/merge
---
2019-09-30T23:19:10.7286040Z    Compiling serde_json v1.0.40
2019-09-30T23:19:12.5286269Z    Compiling tidy v0.1.0 (/checkout/src/tools/tidy)
2019-09-30T23:19:23.9643600Z     Finished release [optimized] target(s) in 1m 31s
2019-09-30T23:19:23.9724490Z tidy check
2019-09-30T23:19:24.8434594Z tidy error: /checkout/src/librustc_typeck/check/mod.rs:4348: line longer than 100 chars
2019-09-30T23:19:24.8434792Z tidy error: /checkout/src/librustc_typeck/check/mod.rs:4349: line longer than 100 chars
2019-09-30T23:19:26.0789513Z some tidy checks failed
2019-09-30T23:19:26.0790510Z 
2019-09-30T23:19:26.0790510Z 
2019-09-30T23:19:26.0791693Z command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor"
2019-09-30T23:19:26.0797371Z 
2019-09-30T23:19:26.0797427Z 
2019-09-30T23:19:26.0808541Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
2019-09-30T23:19:26.0808866Z Build completed unsuccessfully in 0:01:34
2019-09-30T23:19:26.0808866Z Build completed unsuccessfully in 0:01:34
2019-09-30T23:19:26.0865271Z == clock drift check ==
2019-09-30T23:19:26.0880568Z   local time: Mon Sep 30 23:19:26 UTC 2019
2019-09-30T23:19:26.1726195Z   network time: Mon, 30 Sep 2019 23:19:26 GMT
2019-09-30T23:19:26.1729297Z == end clock drift check ==
2019-09-30T23:19:28.0404474Z ##[error]Bash exited with code '1'.
2019-09-30T23:19:28.0440935Z ##[section]Starting: Checkout
2019-09-30T23:19:28.0443110Z ==============================================================================
2019-09-30T23:19:28.0443182Z Task         : Get sources
2019-09-30T23:19:28.0443382Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.

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)

[estebank]

@bors r+

[bors]

📌 Commit 9e4eb46 has been approved by estebank