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parser: don't use unreachable!() in fn unexpected. #66361

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merged 1 commit into from
Nov 14, 2019
Merged

parser: don't use unreachable!() in fn unexpected. #66361

merged 1 commit into from
Nov 14, 2019

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Centril
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@Centril Centril commented Nov 13, 2019

Fixes #66357

r? @estebank

@Centril Centril added beta-nominated Nominated for backporting to the compiler in the beta channel. stable-nominated Nominated for backporting to the compiler in the stable channel. labels Nov 13, 2019
@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Nov 13, 2019
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@bors r+ rollup

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bors commented Nov 13, 2019

📌 Commit dcd91d5 has been approved by pnkfelix

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 13, 2019
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Centril commented Nov 13, 2019

r? @pnkfelix

@rust-highfive rust-highfive assigned pnkfelix and unassigned estebank Nov 13, 2019
JohnTitor added a commit to JohnTitor/rust that referenced this pull request Nov 14, 2019
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Rollup merge of rust-lang#66361 - Centril:66357, r=pnkfelix
8d05997 
parser: don't use `unreachable!()` in `fn unexpected`.

Fixes rust-lang#66357

r? @estebank
@JohnTitor JohnTitor mentioned this pull request Nov 14, 2019
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bors added a commit that referenced this pull request Nov 14, 2019
@bors
Auto merge of #66403 - JohnTitor:rollup-7obuivl, r=JohnTitor
a2491ee 
Rollup of 9 pull requests

Successful merges:

 - #66253 (Improve errors after re rebalance coherence)
 - #66264 (fix an ICE in macro's diagnostic message)
 - #66349 (expand source_util macros with def-site context)
 - #66351 (Tweak non-char/numeric in range pattern diagnostic)
 - #66360 (Fix link to Exten in Vec::set_len)
 - #66361 (parser: don't use `unreachable!()` in `fn unexpected`.)
 - #66363 (Improve error message in make_tests)
 - #66369 (compiletest: Obtain timestamps for common inputs only once)
 - #66372 (Fix broken links in Ipv4Addr::is_benchmarking docs)

Failed merges:

r? @ghost
@bors bors merged commit dcd91d5 into rust-lang:master Nov 14, 2019
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bors commented Nov 14, 2019

☔ The latest upstream changes (presumably #66403) made this pull request unmergeable. Please resolve the merge conflicts.

@bors bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Nov 14, 2019
@Centril Centril deleted the 66357 branch November 14, 2019 11:23
@pnkfelix pnkfelix added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Nov 14, 2019
nikomatsakis
nikomatsakis reviewed Nov 14, 2019
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src/librustc_parse/parser/mod.rs
Ok(_) => unreachable!(),
// We can get `Ok(true)` from `recover_closing_delimiter`
// which is called in `expected_one_of_not_found`.
Ok(_) => FatalError.raise(),
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Remind me -- this is used in the parser as a form of panic? I remember seeing some pretty bad output that resulted from using FatalError.raise() on occasion (I think rustc just failed with no output at all) -- can we not use some other method here?

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Anyway, if this is the "current error handling mechanism" seems fine. I'm just asking for my own edification.

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@estebank estebank Nov 14, 2019 •
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It says "stop the world". The reason we aggressively removed their usages was to enable recovery and plow ahead to type checking even in the face of malformed code. It is a valid strategy to stop the world when a condition that could only have been caused by prior malformed code is met, as at that point continuing with our recovery is a liability, and we will have had errors emitted beforehand.

We might want to have a delay_span_bug as a guardrail, but this should be fine.

@Centril Centril mentioned this pull request Nov 16, 2019
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beta-accepted (last week, sorry for delay!)

@pnkfelix pnkfelix added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Nov 21, 2019
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stable-accepted

@pnkfelix pnkfelix added the stable-accepted Accepted for backporting to the compiler in the stable channel. label Nov 21, 2019
@Mark-Simulacrum Mark-Simulacrum mentioned this pull request Dec 5, 2019
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@Mark-Simulacrum Mark-Simulacrum removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Dec 5, 2019
bors added a commit that referenced this pull request Dec 7, 2019
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Auto merge of #67063 - Mark-Simulacrum:beta-backports, r=Mark-Simulacrum
3f7f341 
[beta] backports

This pull request backports the following pull requests, which have all been beta-accepted by the
compiler team.

 * Handle non_exhaustive in borrow checking #66722
 * Do not ICE on trait aliases with missing obligations #66392
 * Do not ICE in `if` without `else` in `async fn` #66391
 * Fix ICE when trying to suggest `Type<>` instead of `Type()` #66390
 * Do not ICE on recovery from unmet associated type bound obligation #66388
 * find_deprecation: deprecation attr may be ill-formed meta. #66381
 * parser: don't use `unreachable!()` in `fn unexpected`. #66361
 * Undo an assert causing an ICE until we fix the underlying problem #66250
 * Do not ICE with a precision flag in formatting str and no format arguments #66093
 * Fix two OOM issues related to `ConstProp` #66394
bors added a commit that referenced this pull request Dec 8, 2019
@bors
Auto merge of #67063 - Mark-Simulacrum:beta-backports, r=Mark-Simulacrum
b509d9b 
[beta] backports

This pull request backports the following pull requests, which have all been beta-accepted by the
compiler team.

 * Handle non_exhaustive in borrow checking #66722
 * Do not ICE on trait aliases with missing obligations #66392
 * Do not ICE in `if` without `else` in `async fn` #66391
 * Fix ICE when trying to suggest `Type<>` instead of `Type()` #66390
 * Do not ICE on recovery from unmet associated type bound obligation #66388
 * find_deprecation: deprecation attr may be ill-formed meta. #66381
 * parser: don't use `unreachable!()` in `fn unexpected`. #66361
 * Undo an assert causing an ICE until we fix the underlying problem #66250
 * Do not ICE with a precision flag in formatting str and no format arguments #66093
 * Fix two OOM issues related to `ConstProp` #66394
@Mark-Simulacrum Mark-Simulacrum removed stable-accepted Accepted for backporting to the compiler in the stable channel. stable-nominated Nominated for backporting to the compiler in the stable channel. labels Dec 14, 2019
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Internal Compiler Error @ parser.rs:446:22
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