Fix #58270, fix off-by-one error in error diagnostics.

[xldenis]

This fixes#58270 by checking if two diagnostics overlap completely when we're calculating the line offset for each message.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @matthewjasper (or someone else) soon.

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[xldenis]

r? @estebank

[rust-highfive]

The job x86_64-gnu-llvm-6.0 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.

travis_time:end:227a7cca:start=1555899487790897001,finish=1555899574766109539,duration=86975212538
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout
Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
$ export AWS_ACCESS_KEY_ID=AKIA46X5W6CZEJZ6XT55
---
[01:01:44] .................................................................................................... 1600/5549
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---
[01:04:06] 12 LL | let _ = if true {
[01:04:06] 13 LL | });
[01:04:06] - | ^
[01:04:06] - | |
[01:04:06] - | help: `}` may belong here
[01:04:06] + | ^ help: `}` may belong here
[01:04:06] 18 error: expected identifier, found `;`
[01:04:06] 19 --> $DIR/issue-60075.rs:6:11
[01:04:06] [01:04:06] [01:04:06] [01:04:06] The actual stderr differed from the expected stderr.
[01:04:06] Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/issue-60075/issue-60075.stderr
[01:04:06] To update references, rerun the tests and pass the `--bless` flag
[01:04:06] To only update this specific test, also pass `--test-args issue-60075.rs`
[01:04:06] error: 1 errors occurred comparing output.
[01:04:06] status: exit code: 1
[01:04:06] status: exit code: 1
[01:04:06] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/issue-60075.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/issue-60075/a" "-Crpath" "-O" "-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/issue-60075/auxiliary" "-A" "unused"
[01:04:06] ------------------------------------------
[01:04:06] [01:04:06] ------------------------------------------
[01:04:06] stderr:
[01:04:06] stderr:
[01:04:06] ------------------------------------------
[01:04:06] error: expected one of `.`, `;`, `?`, `else`, or an operator, found `}`
[01:04:06] --> /checkout/src/test/ui/issue-60075.rs:6:10
[01:04:06] |
[01:04:06] LL | });
[01:04:06] | ^ expected one of `.`, `;`, `?`, `else`, or an operator here
[01:04:06] [01:04:06] error: expected one of `async`, `const`, `extern`, `fn`, `type`, `unsafe`, or `}`, found `;`
[01:04:06] |
[01:04:06] |
[01:04:06] LL | fn qux() -> Option<usize> {
[01:04:06] LL | let _ = if true {
[01:04:06] LL | });
[01:04:06] LL | });
[01:04:06] | ^ help: `}` may belong here
[01:04:06] error: expected identifier, found `;`
[01:04:06] --> /checkout/src/test/ui/issue-60075.rs:6:11
[01:04:06] |
[01:04:06] LL | });
[01:04:06] LL | });
[01:04:06] | ^ expected identifier
[01:04:06] [01:04:06] error: missing `fn`, `type`, or `const` for trait-item declaration
[01:04:06] |
[01:04:06] LL | });
[01:04:06] | ____________^
[01:04:06] | ____________^
[01:04:06] LL | | //~^ ERROR expected one of `async`, `const`, `extern`, `fn`, `type`, `unsafe`, or `}`, found `;`
[01:04:06] LL | | //~^^ ERROR expected one of `.`, `;`, `?`, `else`, or an operator, found `}`
[01:04:06] LL | | //~^^^ ERROR 6:11: 6:12: expected identifier, found `;`
[01:04:06] LL | | //~^^^^ ERROR missing `fn`, `type`, or `const` for trait-item declaration
[01:04:06] LL | | Some(4)
[01:04:06] | |________^ missing `fn`, `type`, or `const`
[01:04:06] error: aborting due to 4 previous errors
[01:04:06] [01:04:06] [01:04:06] ------------------------------------------
---
[01:04:06] thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:517:22
[01:04:06] note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
[01:04:06] [01:04:06] [01:04:06] 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" "/usr/lib/llvm-6.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -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" "--quiet" "--llvm-version" "6.0.0\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[01:04:06] [01:04:06] [01:04:06] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:04:06] Build completed unsuccessfully in 0:04:12
[01:04:06] Build completed unsuccessfully in 0:04:12
[01:04:06] make: *** [check] Error 1
[01:04:06] Makefile:48: recipe for target 'check' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:000820d7
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Mon Apr 22 03:23:51 UTC 2019
---
travis_time:end:0466e6d8:start=1555903432284424674,finish=1555903432291287735,duration=6863061
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:1699aeb0
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:26fd3bd9
$ dmesg | grep -i kill

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[estebank]

The change looks good. You'll have to rebase información top of latest master and rerun bless, but other than that r=me.

[xldenis]

r=estebank I rebased an ran bless (it updated one test case).

[estebank]

@bors r+

[bors]

📌 Commit 4a073dd has been approved by estebank

[bors]

⌛ Testing commit 4a073dd with merge 9aea116...