[nll] improve the "fully elaborated type" case in region errors #52648

davidtwco · 2018-07-23T14:38:20Z

davidtwco · 2018-07-23T14:39:16Z

This currently uses the slightly-yucky string manipulation approach that we spoke about briefly in Zulip @nikomatsakis. If this isn't the way we want to do it then I'm happy to change it.

csmoe · 2018-07-23T15:02:46Z

src/test/ui/issue-52533.nll.stderr

+LL |     foo(|a, b| b)
+   |          -  -  ^ closure was supposed to return data with lifetime `'1` but it is returning data with lifetime `'2`
+   |          |  |
+   |          |  has type `&'1u32`


maybe missing whitespace between region and type(u32)?

Oops! Thanks, never spotted these when looking through the changed tests, pushed a fix for that.

nikomatsakis

So the string manipulation doesn't feel great but we do have to decide what would be a better way...

nikomatsakis · 2018-07-24T20:09:59Z

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs

+        match (category, outlived_fr_is_local, fr_is_local) {
+            (ConstraintCategory::Return, true, _) => {
+                diag.span_label(*span, format!(
+                    "closure was supposed to return data with lifetime `{}` but it is returning \


probably here we don't want to say closure necessarily?

Fixed this to match the rest of the PR that detects "function" or "closure" based on the mir_def_id.

nikomatsakis · 2018-07-24T20:12:28Z

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs

+    ///  |          |  has type `&'1 u32`
+    ///  |          has type `&'2 u32`
+    /// ```
+    fn give_name_if_we_cannot_match_hir_ty(


huh, this is pretty grody

Addressed this with most recent commit.

nikomatsakis · 2018-07-26T11:47:00Z

src/librustc/util/ppaux.rs

@@ -32,6 +32,10 @@ use syntax::ast::CRATE_NODE_ID;
 use syntax::symbol::{Symbol, InternedString};
 use hir;

+thread_local! {


comment please =)

Updated most recent commit to address this.

nikomatsakis · 2018-07-26T11:47:35Z

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs

 use rustc_errors::DiagnosticBuilder;
 use syntax::ast::Name;
 use syntax::symbol::keywords;
 use syntax_pos::symbol::InternedString;

+fn with_highlight_region<R>(r: RegionVid, counter: usize, op: impl FnOnce() -> R) -> R {


I'd probably put this code into ppaux and encapsulate the HIGHLIGHT_REGION variable itself

Updated most recent commit to address this.

nikomatsakis · 2018-07-26T11:48:15Z

src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr

   |                                                |
-   |                                                has type `&'1 std::cell::Cell<&'2 &'3 u32>`
+   |                                                has type `&'_ std::cell::Cell<&'1 &'_ u32>`


as an aside, it might be nice to not print '_ in this case but just &

Updated most recent commit to address this.

nikomatsakis · 2018-07-26T11:48:37Z

src/test/ui/error-codes/E0621-does-not-trigger-for-closures.nll.stderr

@@ -11,7 +11,7 @@ LL |     invoke(&x, |a, b| if a > b { a } else { b }); //~ ERROR E0495
   |                ----------^^^^^-----------------
   |                |   |     |
   |                |   |     free region requires that `'1` must outlive `'2`
-   |                |   has type `&'1 i32`
+   |                |   lifetime `'1` appears in this argument


so wait why this diff?

oh because we don't find the '1 at all?

Updated most recent commit to address this.

nikomatsakis · 2018-07-26T12:41:50Z

src/librustc/util/ppaux.rs

+            return if *self == region {
+                write!(f, "'{:?}", counter)
+            } else {
+                write!(f, "")


well, I know I sort of asked for this, but I think in a way I liked '_ better -- in particular, I'd like to see a test that shows what happens when you elaborate a struct type like TyCtxt -- I'd like to see TyCtxt<'_, '1, '_>, in particular. =)

I think instead I would modify the TyRef code to look for either "'_" or "" and just skip printing in that case.

Fixed this in recent commit.

nikomatsakis · 2018-07-26T13:46:59Z

src/test/ui/issue-52533-1.nll.stderr

+   |            -  -  ^ closure was supposed to return data with lifetime `'1` but it is returning data with lifetime `'2`
+   |            |  |
+   |            |  has type `&Foo<'_, '1, u32>`
+   |            has type `&Foo<'_, '2, u32>`


this is so beautiful

rust-highfive · 2018-07-26T13:57:15Z

The job x86_64-gnu-llvm-5.0 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.


[00:03:51] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:03:51] tidy error: /checkout/src/test/ui/issue-52533-1.rs:15: line longer than 100 chars
[00:03:52] some tidy checks failed
[00:03:52] 
[00:03:52] 
[00:03:52] 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" "--quiet"
[00:03:52] 
[00:03:52] 
[00:03:52] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:03:52] Build completed unsuccessfully in 0:00:52
[00:03:52] Build completed unsuccessfully in 0:00:52
[00:03:52] make: *** [tidy] Error 1
[00:03:52] Makefile:79: recipe for target 'tidy' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:2647392c
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
---
travis_time:end:01968cb4:start=1532612962366536213,finish=1532612962374473488,duration=7937275
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:1e554640
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:07a4938d
travis_time:start:07a4938d
$ 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:01320810
$ dmesg | grep -i kill

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)

davidtwco · 2018-07-26T13:59:31Z

Oops! Fixed that.

nikomatsakis · 2018-07-26T14:44:35Z

@bors r+

bors · 2018-07-26T14:44:35Z

📌 Commit 3efc77b464330a0462f0f7036f77a8eff77d1363 has been approved by nikomatsakis

rust-highfive · 2018-07-26T14:45:50Z

The job x86_64-gnu-llvm-5.0 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.

[00:43:12] ....................................................................................................
[00:43:14] ....................................................................................................
[00:43:17] ....................................................................................................
[00:43:20] ....................................................................................................
[00:43:23] ...................................................................F................................
[00:43:30] ......................................................i.............................................
[00:43:33] ...............................................i....................................................
[00:43:36] ....................................................................................................
[00:43:40] ....................................................................................................
---
[00:43:46] 1 error[E0308]: mismatched types
[00:43:46] -   --> $DIR/issue-52533-1.rs:18:18
[00:43:46] +   --> $DIR/issue-52533-1.rs:19:18
[00:43:46] 3    |
[00:43:46] 4 LL |     gimme(|x, y| y)
[00:43:46] 5    |                  ^ lifetime mismatch
[00:43:46] 6    |
[00:43:46] 6    |
[00:43:46] 7    = note: expected type `&Foo<'_, '_, u32>`
[00:43:46] 8               found type `&Foo<'_, '_, u32>`
[00:43:46] - note: the anonymous lifetime #4 defined on the body at 18:11...
[00:43:46] -   --> $DIR/issue-52533-1.rs:18:11
[00:43:46] + note: the anonymous lifetime #4 defined on the body at 19:11...
[00:43:46] +   --> $DIR/issue-52533-1.rs:19:11
[00:43:46] 11    |
[00:43:46] 12 LL |     gimme(|x, y| y)
[00:43:46] 
[00:43:46] 
[00:43:46] - note: ...does not necessarily outlive the anonymous lifeus lifetime #3 defined on the body at 19:11","code":null,"level":"note","spans":[{"file_name":"/checkout/src/test/ui/issue-52533-1.rs","byte_start":719,"byte_end":727,"line_start":19,"line_end":19,"column_start":11,"column_end":19,"is_primary":true,"text":[{"text":"    gimme(|x, y| y)","highlight_start":11,"highlight_end":19}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":null}],"rendered":"error[E0308]: mismatched types\n  --> /checkout/src/test/ui/issue-52533-1.rs:19:18\n   |\nLL |     gimme(|x, y| y)\n   |                  ^ lifetime mismatch\n   |\n   = note: expected type `&Foo<'_, '_, u32>`\n              found type `&Foo<'_, '_, u32>`\nnote: the anonymous lifetime #4 defined on the body at 19:11...\n  --> /checkout/src/test/ui/issue-52533-1.rs:19:11\n   |\nLL |     gimme(|x, y| y)\n   |           ^^^^^^^^\nnote: ...does not necessarily outlive the anonymous lifetime #3 defined on the body at 19:11\n  --> /checkout/src/test/ui/issue-52533-1.rs:19:11\n   |\nLL |     gimme(|x, y| y)\n   |           ^^^^^^^^\n\n"}
[00:43:46] {"message":"aborting due to previous error","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to previous error\n\n"}
[00:43:46] {"message":"For more information about this error, try `rustc --explain E0308`.","code":null,"level":"","spans":[],"children":[],"rendered":"For more information about this error, try `rustc --explain E0308`.\n"}
[00:43:46] ------------------------------------------
[00:43:46] 
[00:43:46] thread '[ui] ui/issue-52533-1.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:3141:9
[00:43:46] note: Run with `RUST_BACKTRACE=1` for a backtrace.
---
[00:43:46] 
[00:43:46] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:498:22
[00:43:46] 
[00:43:46] 
[00:43:46] 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-5.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options " "--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" "5.0.0\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
travis_time:end:1c5ad088:start=1532613719537317861,finish=1532616346212522631,duration=2626675204770

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:21232900

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)

davidtwco · 2018-07-26T14:51:48Z

Oops again! Fixed that.

nikomatsakis · 2018-07-26T16:17:48Z

@bors r+ p=1

bors · 2018-07-26T16:17:49Z

📌 Commit 301e4da54648f9fdeff0865048e2c6ade258a58b has been approved by nikomatsakis

Mark-Simulacrum · 2018-07-26T16:17:49Z

@bors r=nikomatsakis p=1 NLL critical

bors · 2018-07-26T16:17:50Z

💡 This pull request was already approved, no need to approve it again.

There's another pull request that is currently being tested, blocking this pull request: introduce universes to NLL type check #52488

bors · 2018-07-26T16:17:50Z

📌 Commit 301e4da54648f9fdeff0865048e2c6ade258a58b has been approved by nikomatsakis

kennytm · 2018-07-26T22:18:10Z

@bors r-

Merge conflict ↓

…gions.

davidtwco · 2018-07-27T11:15:46Z

Rebased!

Mark-Simulacrum · 2018-07-27T11:41:58Z

@bors r=nikomatsakis p=1

bors · 2018-07-27T11:41:59Z

📌 Commit 2e4224a has been approved by nikomatsakis

bors · 2018-07-27T13:01:56Z

⌛ Testing commit 2e4224a with merge b6cbc1e...

@nikomatsakis

[nll] improve the "fully elaborated type" case in region errors Fixes #52533. r? @nikomatsakis

bors · 2018-07-27T15:03:27Z

☀️ Test successful - status-appveyor, status-travis
Approved by: nikomatsakis
Pushing b6cbc1e to master...

rust-highfive assigned nikomatsakis Jul 23, 2018

davidtwco changed the title ~~[nll] improve the "fully elaborated type" case in region errors~~ WIP: [nll] improve the "fully elaborated type" case in region errors Jul 23, 2018

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 23, 2018

csmoe reviewed Jul 23, 2018

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nikomatsakis requested changes Jul 24, 2018

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davidtwco force-pushed the issue-52533 branch 3 times, most recently from 98e4cb2 to 70ed4e2 Compare July 26, 2018 10:30

nikomatsakis requested changes Jul 26, 2018

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davidtwco force-pushed the issue-52533 branch from 70ed4e2 to 92d1fd0 Compare July 26, 2018 12:38

nikomatsakis requested changes Jul 26, 2018

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davidtwco force-pushed the issue-52533 branch from 92d1fd0 to 1933f1d Compare July 26, 2018 13:43

nikomatsakis approved these changes Jul 26, 2018

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nikomatsakis changed the title ~~WIP: [nll] improve the "fully elaborated type" case in region errors~~ [nll] improve the "fully elaborated type" case in region errors Jul 26, 2018

davidtwco force-pushed the issue-52533 branch from 1933f1d to 3efc77b Compare July 26, 2018 13:59

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 Jul 26, 2018

davidtwco force-pushed the issue-52533 branch from 3efc77b to 301e4da Compare July 26, 2018 14:51

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 Jul 26, 2018

davidtwco added 8 commits July 27, 2018 11:18

Simplified closure handling to need no new cosntraint categories.

41ce2e9

Added fully elaborated type label for inferred arguments.

53dda8e

Improved fully elaborated type generation to replace '_#2r-style re…

d4be95f

…gions.

Update affected tests.

5282d7d

Fixed missing whitespace on some elaborated types.

055aaaf

Change label from closure to function where appropriate.

b377e7b

Improved mechanism for naming regions in non-annotated types.

f44807a

Region inference error messages no longer start with 'free region'

2e4224a

davidtwco force-pushed the issue-52533 branch from 301e4da to 2e4224a Compare July 27, 2018 11:15

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 Jul 27, 2018

bors added a commit that referenced this pull request Jul 27, 2018

Auto merge of #52648 - davidtwco:issue-52533, r=nikomatsakis

b6cbc1e

[nll] improve the "fully elaborated type" case in region errors Fixes #52533. r? @nikomatsakis

bors merged commit 2e4224a into rust-lang:master Jul 27, 2018

davidtwco deleted the issue-52533 branch July 27, 2018 15:09

davidtwco mentioned this pull request Jul 27, 2018

NLL: need to capture and present causes that led to region constraints #51188

Closed

pnkfelix mentioned this pull request Aug 1, 2018

NLL: need a (new) round of review of deltas between .stderr and .nll.stderr output #52663

Closed

pnkfelix mentioned this pull request Oct 9, 2018

error: internal compiler error: Accessing (*_310) with the kind Write(Move) shouldn't be possible #54597

Closed

[nll] improve the "fully elaborated type" case in region errors #52648

[nll] improve the "fully elaborated type" case in region errors #52648

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rust-highfive commented Jul 26, 2018

davidtwco commented Jul 26, 2018

nikomatsakis commented Jul 26, 2018

bors commented Jul 26, 2018

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bors commented Jul 26, 2018

Mark-Simulacrum commented Jul 26, 2018

bors commented Jul 26, 2018

bors commented Jul 26, 2018

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davidtwco commented Jul 27, 2018

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bors commented Jul 27, 2018

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bors commented Jul 27, 2018