Debug #48116.#48127

kennytm · 2018-02-10T21:08:09Z

When the invalid condition is hit, write out the relevant variables too
In compile-fail/parse-fail tests, check for ICE first, so the invalid error patterns won't mask our ICE output.

eddyb · 2018-02-10T21:13:01Z

bors · 2018-02-10T21:13:02Z

📌 Commit 9f015ee has been approved by eddyb

bors · 2018-02-10T22:42:01Z

☔ The latest upstream changes (presumably #48113) made this pull request unmergeable. Please resolve the merge conflicts.

estebank · 2018-02-10T23:10:28Z

@kennytm Needs rebase.

kennytm · 2018-02-11T06:22:57Z

Okay okay

kennytm · 2018-02-11T06:26:34Z

@bors r=eddyb

bors · 2018-02-11T06:26:35Z

📌 Commit 3337d51 has been approved by eddyb

bors · 2018-02-11T08:21:34Z

⌛ Testing commit 3337d51 with merge 790e7b2fcfdefa3b583b45d05b20c7de9862d5c4...

bors · 2018-02-11T10:16:10Z

💔 Test failed - status-travis

kennytm · 2018-02-11T10:36:48Z

Perfect, hit #48116 😂

I think we could take a look at the result before retrying.

x = "::extern"
span = Span { lo: BytePos(525), hi: BytePos(531), ctxt: #0 }
global = false,
names = [],

subclass =

SingleImport { 
    target: extern#0, 
    source: extern#0, 
    result: PerNS { 
        value_ns: Cell { value: Err(Determined) }, 
        type_ns: Cell { value: Err(Determined) }, 
        macro_ns: None 
    }, 
    type_ns_only: false 
}

Details

[01:51:01] failures:
[01:51:01] 
[01:51:01] ---- [compile-fail] compile-fail/rfc-2126-extern-in-paths/single-segment.rs stdout ----
[01:51:01] 	
[01:51:01] error: compiler encountered internal error
[01:51:01] status: exit code: 101
[01:51:01] command: "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/stage2/bin/rustc" "/Users/travis/build/rust-lang/rust/src/test/compile-fail/rfc-2126-extern-in-paths/single-segment.rs" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail" "--target=x86_64-apple-darwin" "--error-format" "json" "-C" "prefer-dynamic" "-o" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/rfc-2126-extern-in-paths/single-segment.stage2-x86_64-apple-darwin" "-Crpath" "-O" "-Zmiri" "-Zunstable-options" "-Lnative=/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/native/rust-test-helpers" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/rfc-2126-extern-in-paths/single-segment.stage2-x86_64-apple-darwin.aux" "-A" "unused"
[01:51:01] stdout:
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] stderr:
[01:51:01] ------------------------------------------
[01:51:01] {"message":"unresolved import `extern::*`","code":{"code":"E0432","explanation":"\nAn import was unresolved.\n\nErroneous code example:\n\n```compile_fail,E0432\nuse something::Foo; // error: unresolved import `something::Foo`.\n```\n\nPaths in `use` statements are relative to the crate root. To import items\nrelative to the current and parent modules, use the `self::` and `super::`\nprefixes, respectively. Also verify that you didn't misspell the import\nname and that the import exists in the module from where you tried to\nimport it. Example:\n\n```\nuse self::something::Foo; // ok!\n\nmod something {\n    pub struct Foo;\n}\n# fn main() {}\n```\n\nOr, if you tried to use a module from an external crate, you may have missed\nthe `extern crate` declaration (which is usually placed in the crate root):\n\n```\nextern crate core; // Required to use the `core` crate\n\nuse core::any;\n# fn main() {}\n```\n"},"level":"error","spans":[{"file_name":"/Users/travis/build/rust-lang/rust/src/test/compile-fail/rfc-2126-extern-in-paths/single-segment.rs","byte_start":620,"byte_end":629,"line_start":17,"line_end":17,"column_start":5,"column_end":14,"is_primary":true,"text":[{"text":"use extern::*; //~ ERROR unresolved import `extern::*`","highlight_start":5,"highlight_end":14}],"label":"cannot glob-import all possible crates","suggested_replacement":null,"expansion":null}],"children":[],"rendered":"error[E0432]: unresolved import `extern::*`\n  --> /Users/travis/build/rust-lang/rust/src/test/compile-fail/rfc-2126-extern-in-paths/single-segment.rs:17:5\n   |\n17 | use extern::*; //~ ERROR unresolved import `extern::*`\n   |     ^^^^^^^^^ cannot glob-import all possible crates\n\n"}
[01:51:01] thread 'rustc' panicked at 'librustc_resolve/resolve_imports.rs:1040: invalid name `::extern` at Span { lo: BytePos(525), hi: BytePos(531), ctxt: #0 }; global = false, names = [], subclass = SingleImport { target: extern#0, source: extern#0, result: PerNS { value_ns: Cell { value: Err(Determined) }, type_ns: Cell { value: Err(Determined) }, macro_ns: None }, type_ns_only: false }', librustc/session/mod.rs:1180:26
[01:51:01] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:51:01] 
[01:51:01] error: internal compiler error: unexpected panic
[01:51:01] 
[01:51:01] note: the compiler unexpectedly panicked. this is a bug.
[01:51:01] 
[01:51:01] note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
[01:51:01] 
[01:51:01] note: rustc 1.25.0-dev running on x86_64-apple-darwin
[01:51:01] 
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] thread '[compile-fail] compile-fail/rfc-2126-extern-in-paths/single-segment.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:2883:9
[01:51:01] 
[01:51:01] ---- [compile-fail] compile-fail/use-keyword.rs stdout ----
[01:51:01] 	
[01:51:01] error: compiler encountered internal error
[01:51:01] status: exit code: 101
[01:51:01] command: "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/stage2/bin/rustc" "/Users/travis/build/rust-lang/rust/src/test/compile-fail/use-keyword.rs" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail" "--target=x86_64-apple-darwin" "--error-format" "json" "-C" "prefer-dynamic" "-o" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/use-keyword.stage2-x86_64-apple-darwin" "-Crpath" "-O" "-Zmiri" "-Zunstable-options" "-Lnative=/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/native/rust-test-helpers" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/use-keyword.stage2-x86_64-apple-darwin.aux" "-A" "unused"
[01:51:01] stdout:
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] stderr:
[01:51:01] ------------------------------------------
[01:51:01] {"message":"`self` imports are only allowed within a { } list","code":{"code":"E0429","explanation":"\nThe `self` keyword cannot appear alone as the last segment in a `use`\ndeclaration.\n\nErroneous code example:\n\n```compile_fail,E0429\nuse std::fmt::self; // error: `self` imports are only allowed within a { } list\n```\n\nTo use a namespace itself in addition to some of its members, `self` may appear\nas part of a brace-enclosed list of imports:\n\n```\nuse std::fmt::{self, Debug};\n```\n\nIf you only want to import the namespace, do so directly:\n\n```\nuse std::fmt;\n```\n"},"level":"error","spans":[{"file_name":"/Users/travis/build/rust-lang/rust/src/test/compile-fail/use-keyword.rs","byte_start":634,"byte_end":643,"line_start":16,"line_end":16,"column_start":13,"column_end":22,"is_primary":true,"text":[{"text":"        use self as A;","highlight_start":13,"highlight_end":22}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[],"rendered":"error[E0429]: `self` imports are only allowed within a { } list\n  --> /Users/travis/build/rust-lang/rust/src/test/compile-fail/use-keyword.rs:16:13\n   |\n16 |         use self as A;\n   |             ^^^^^^^^^\n\n"}
[01:51:01] thread 'rustc' panicked at 'librustc_resolve/resolve_imports.rs:1040: invalid name `::super` at Span { lo: BytePos(726), hi: BytePos(736), ctxt: #0 }; global = false, names = [], subclass = SingleImport { target: B#0, source: super#0, result: PerNS { value_ns: Cell { value: Err(Determined) }, type_ns: Cell { value: Err(Determined) }, macro_ns: None }, type_ns_only: false }', librustc/session/mod.rs:1180:26
[01:51:01] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:51:01] 
[01:51:01] error: internal compiler error: unexpected panic
[01:51:01] 
[01:51:01] note: the compiler unexpectedly panicked. this is a bug.
[01:51:01] 
[01:51:01] note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
[01:51:01] 
[01:51:01] note: rustc 1.25.0-dev running on x86_64-apple-darwin
[01:51:01] 
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] thread '[compile-fail] compile-fail/use-keyword.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:2883:9
[01:51:01] 
[01:51:01] ---- [compile-fail] compile-fail/use-mod-2.rs stdout ----
[01:51:01] 	
[01:51:01] error: compiler encountered internal error
[01:51:01] status: exit code: 101
[01:51:01] command: "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/stage2/bin/rustc" "/Users/travis/build/rust-lang/rust/src/test/compile-fail/use-mod-2.rs" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail" "--target=x86_64-apple-darwin" "--error-format" "json" "-C" "prefer-dynamic" "-o" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/use-mod-2.stage2-x86_64-apple-darwin" "-Crpath" "-O" "-Zmiri" "-Zunstable-options" "-Lnative=/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/native/rust-test-helpers" "-L" "/Users/travis/build/rust-lang/rust/build/x86_64-apple-darwin/test/compile-fail/use-mod-2.stage2-x86_64-apple-darwin.aux" "-A" "unused"
[01:51:01] stdout:
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] stderr:
[01:51:01] ------------------------------------------
[01:51:01] thread 'rustc' panicked at 'librustc_resolve/resolve_imports.rs:1040: invalid name `::self` at Span { lo: BytePos(492), hi: BytePos(496), ctxt: #0 }; global = false, names = [], subclass = SingleImport { target: self#0, source: self#0, result: PerNS { value_ns: Cell { value: Err(Undetermined) }, type_ns: Cell { value: Err(Determined) }, macro_ns: None }, type_ns_only: true }', librustc/session/mod.rs:1180:26
[01:51:01] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:51:01] 
[01:51:01] error: internal compiler error: unexpected panic
[01:51:01] 
[01:51:01] note: the compiler unexpectedly panicked. this is a bug.
[01:51:01] 
[01:51:01] note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
[01:51:01] 
[01:51:01] note: rustc 1.25.0-dev running on x86_64-apple-darwin
[01:51:01] 
[01:51:01] 
[01:51:01] ------------------------------------------
[01:51:01] 
[01:51:01] thread '[compile-fail] compile-fail/use-mod-2.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:2883:9
[01:51:01] 
[01:51:01] 
[01:51:01] failures:
[01:51:01]     [compile-fail] compile-fail/rfc-2126-extern-in-paths/single-segment.rs
[01:51:01]     [compile-fail] compile-fail/use-keyword.rs
[01:51:01]     [compile-fail] compile-fail/use-mod-2.rs

eddyb · 2018-02-11T10:57:35Z

Okay, looks like outer if names.is_empty() is broken and enters the else for some reason.

alexcrichton · 2018-02-11T16:04:08Z

What I'm curious about is what in the world is nondeterministic to cause this?

kennytm · 2018-02-11T17:01:12Z

Since we've got the reason of failure, I'm transforming this PR for debugging.

kennytm · 2018-02-11T18:15:19Z

@bors try

bors · 2018-02-11T18:15:29Z

⌛ Trying commit b292325 with merge 36d3769...

@alexcrichton

[WIP] Debug #48116. 1. When the invalid condition is hit, write out the relevant variables too 2. In compile-fail/parse-fail tests, check for ICE first, so the invalid error patterns won't mask our ICE output. r? @alexcrichton cc #48116, cc @eddyb

bors · 2018-02-11T19:38:17Z

💔 Test failed - status-travis

1. When the invalid condition is hit, write out the relevant variables too 2. In compile-fail/parse-fail tests, check for ICE first, so the invalid error patterns won't mask our ICE output.

kennytm · 2018-02-13T07:21:38Z

(Needs to test the magic power of the auto branch. The PR should fail immediately, so it shouldn't block the queue.)

@bors r+ p=52

bors · 2018-02-13T07:21:38Z

📌 Commit 4f95269 has been approved by kennytm

bors · 2018-02-13T09:49:16Z

⌛ Testing commit 4f95269 with merge 3ca6eed5832800d513ead5f11927ed1a4f7bf2ef...

bors · 2018-02-13T09:52:05Z

💔 Test failed - status-travis

kennytm · 2018-02-13T09:57:23Z

cancelbot is too aggressive, there should be some way to let cancelbot ignore manual restarts... 😐

@eddyb

Try to fix 48116 and 48192 The bug #48116 happens because of a misoptimization of the `import_path_to_string` function, where a `names` slice is empty but the `!names.is_empty()` branch is executed. https://github.com/rust-lang/rust/blob/4d2d3fc5dadf894a8ad709a5860a549f2c0b1032/src/librustc_resolve/resolve_imports.rs#L1015-L1042 Yesterday, @eddyb had locally reproduced the bug, and [came across the `position` function](https://mozilla.logbot.info/rust-infra/20180214#c14296834) where the `assume()` call is found to be suspicious. We have *not* concluded that this `assume()` causes #48116, but given [the reputation of `assume()`](#45501 (comment)), this seems higher relevant. Here we try to see if commenting it out can fix the errors. Later @alexcrichton has bisected and found a potential bug [in the LLVM side](#48116 (comment)). We are currently testing if reverting that LLVM commit is enough to stop the bug. If true, this PR can be reverted (keep the `assume()`) and we could backport the LLVM patch instead. (This PR also includes an earlier commit from #48127 for help debugging ICE happening in compile-fail/parse-fail tests.) The PR also reverts #48059, which seems to cause #48192. r? @alexcrichton cc @eddyb, @arthurprs (#47333)

kennytm added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 10, 2018

rust-highfive assigned alexcrichton Feb 10, 2018

kennytm mentioned this pull request Feb 10, 2018

Spurious (?) error in "compile-fail\rfc-2126-extern-in-paths\single-segment.rs" etc #48116

Closed

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 Feb 10, 2018

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 Feb 10, 2018

kennytm force-pushed the debug-48116 branch from 9f015ee to 3337d51 Compare February 11, 2018 06:26

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Feb 11, 2018

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Feb 11, 2018

kennytm 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-review Status: Awaiting review from the assignee but also interested parties. labels Feb 11, 2018

kennytm changed the title ~~Improve debuggability of #48116.~~ [WIP] Debug #48116. Feb 11, 2018

Improve debuggability of rust-lang#48116.

3878906

1. When the invalid condition is hit, write out the relevant variables too 2. In compile-fail/parse-fail tests, check for ICE first, so the invalid error patterns won't mask our ICE output.

kennytm force-pushed the debug-48116 branch 2 times, most recently from d2ca440 to 7c54f2a Compare February 13, 2018 07:12

kennytm added 2 commits February 13, 2018 15:17

Convert the CI to debug 48116 only.

d07378d

Add some necessary tracing commands.

4f95269

kennytm force-pushed the debug-48116 branch from 7c54f2a to 4f95269 Compare February 13, 2018 07:17

kennytm changed the title ~~[WIP] Debug #48116.~~ Debug #48116. Feb 13, 2018

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Feb 13, 2018

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Feb 13, 2018

kennytm 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-review Status: Awaiting review from the assignee but also interested parties. labels Feb 13, 2018

kennytm closed this Feb 14, 2018

kennytm deleted the debug-48116 branch February 14, 2018 15:19

kennytm mentioned this pull request Feb 14, 2018

Try to fix 48116 and 48192 #48209

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