Suggest only Span without source changes when source code is unavailable by xizheyin · Pull Request #144585 · rust-lang/rust

xizheyin · 2025-07-28T14:09:07Z

UI tests hide std library sources so diagnostics match what users may see when std sources are unavailable.
In those cases, suggestions whose spans point into std macros cannot be rendered as source patches.

Before this change, if all substitutions for a suggestion were filtered out because the source could not be loaded, the suggestion was dropped entirely. This meant useful help messages could disappear in UI test output, while it will appear in user's terminal.

This adds a -Zshow-suggestions-with-unavailable-source flag and enables it for UI tests. When the annotate-snippet emitter cannot render a suggestion as a patch, but the original suggestion points to unavailable source, it now emits a span-only help instead:

help: consider using `drop` function
  --> $SRC_DIR/core/src/macros/mod.rs:LL:COL

cc #139316 (comment)

rustbot · 2025-07-28T14:09:12Z

jieyouxu is currently at their maximum review capacity.
They may take a while to respond.

rustbot · 2025-07-28T14:09:16Z

Some changes occurred in src/tools/compiletest

cc @jieyouxu

xizheyin · 2025-07-28T14:10:39Z

Looks like jieyou is busy

r? compiler

jieyouxu · 2025-07-28T14:25:41Z

This feels very sus. How does this handle stable vs beta vs nightly vs in-tree std sources?

I feel like there's a reason why ui tests don't get to access std sources, which is to prevent different diagnostics depending on availability of std sources, and which std sources?

xizheyin · 2025-07-28T14:40:42Z

How does this handle stable vs beta vs nightly vs in-tree std sources?

Is it possible to normalize the content of the source code and just let us know that the source code is displayed in stderr?

I'm curious what kind of impact different versions (stable/nightly/beta/in-tree) would have, I don't know enough about CI. Any examples of this?

xizheyin · 2025-07-28T14:57:43Z

Path remapped is introduced in #105500 may cc @oli-obk
Indeed it's not that simple, some of the existing test surprisingly shows something like

note: required by a bound in `Option`
  --> $SRC_DIR/core/src/option.rs:LL:COL

, just without the source code...

xizheyin · 2025-07-30T19:31:13Z

For further explanation, I moved the comments here.

When fixing the problems listed in #142403, we found that the bug could not be reproduced in ui test. After investigation, I found that span suggestion and span note are not realized in the same way, so I submitted this pr to make std visible in ui tests.

In daily use, the source of std should be visible, and execution will fall to the else branch, so these will not be displayed.

This new test is a bug recorded in #142403, only for verifying this code change, I will fix it in later pr.

xizheyin · 2025-08-07T12:05:06Z

r? @estebank

xizheyin

I set it as a new zflag, enabled only during UI tests: if the source code isn't available, then print "span".

The results were as expected; the blessed UI test exposed some existing diagnostic bugs in the compiler, printing the contents of external macros(in std library). However, I think this might need to be fixed in a future PR.

@rustbot ready

View changes since this review

xizheyin · 2026-05-25T09:03:47Z

+    show_suggestions_with_unavailable_source: bool = (false, parse_bool, [UNTRACKED],
+        "show span-only suggestions when the source code is unavailable"),


I added a option show_suggestions_with_unavailable_source.

xizheyin · 2026-05-25T09:04:55Z

+help: check for equality instead of pattern matching
+  --> $SRC_DIR/alloc/src/macros.rs:LL:COL


diagnostic bug?

I'm assuming we end up with a span into the vec![] expansion instead of its callsite.

estebank · 2026-10-08T16:40:43Z

Apologies for the delay on reviewing this. r=me after rebase.

The code changes look good, every single suggestion being shown has a wrong span (because of macros, as usual). We should fix those suggestions in separate PRs, eventually.

rustbot · 2026-10-09T10:49:07Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

estebank · 2026-10-09T15:39:51Z

@bors r+

rust-bors · 2026-10-09T15:39:57Z

📌 Commit 3940850 has been approved by estebank

It is now in the queue for this repository.

Suggest only Span without source changes when source code is unavailable UI tests hide std library sources so diagnostics match what users may see when std sources are unavailable. In those cases, suggestions whose spans point into std macros cannot be rendered as source patches. Before this change, if all substitutions for a suggestion were filtered out because the source could not be loaded, the suggestion was dropped entirely. This meant useful help messages could disappear in UI test output, while it will appear in user's terminal. This adds a `-Zshow-suggestions-with-unavailable-source` flag and enables it for UI tests. When the annotate-snippet emitter cannot render a suggestion as a patch, but the original suggestion points to unavailable source, it now emits a span-only help instead: ```text help: consider using `drop` function --> $SRC_DIR/core/src/macros/mod.rs:LL:COL ``` cc rust-lang#139316 (comment)

JonathanBrouwer · 2026-10-09T17:37:11Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #164048 (comment)

rust-bors · 2026-10-09T17:37:21Z

This pull request was unapproved.

This PR was contained in a rollup (#164048), which was unapproved.

View changes since this unapproval

xizheyin · 2026-10-09T19:17:24Z

                compiler.arg("-Zwrite-long-types-to-disk=no");
                // FIXME: use this for other modes too, for perf?
                compiler.arg("-Cstrip=debuginfo");
+                if self.config.suite != TestSuite::UiFullDeps {


I walked around the code, find in stage1 and ui-fulldeps it changes test_compiler to stage0

if suite == "ui-fulldeps" && test_compiler.stage == 1

I did a temp fix, supressing the flag in uifulldeps...but this is a bit strange—do you have any good ideas?@jieyouxu

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rustbot assigned jieyouxu Jul 28, 2025

rustbot assigned SparrowLii and unassigned jieyouxu Jul 28, 2025

xizheyin mentioned this pull request Jul 28, 2025

Do not suggest compatible variants inside macro #142611

Merged

fmease reviewed Jul 28, 2025

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Comment thread tests/ui/compiletest-self-test/show-std-source-without-flag.rs Outdated

xizheyin marked this pull request as draft July 28, 2025 15:49

rustbot 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 Jul 28, 2025

jieyouxu mentioned this pull request Jul 28, 2025

Diagnostics differ between regular execution and ui tests #131782

Open

xizheyin changed the title ~~Add compiletest directive show-std-source~~ Suggest only Span without source changes when source code is unavailable Jul 28, 2025

xizheyin force-pushed the show-std-source branch from fef27bc to 1eb0f64 Compare July 28, 2025 17:39

xizheyin commented Jul 28, 2025

View reviewed changes

Comment thread tests/ui/compiletest-self-test/help-show-std-source.stderr Outdated

xizheyin marked this pull request as ready for review July 28, 2025 17:44

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 28, 2025

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xizheyin marked this pull request as draft May 25, 2026 04:48

xizheyin force-pushed the show-std-source branch 2 times, most recently from 5b01eb6 to 5b0b080 Compare May 25, 2026 09:01

xizheyin commented May 25, 2026

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xizheyin marked this pull request as ready for review May 25, 2026 09:09

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estebank 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 Oct 8, 2026

xizheyin force-pushed the show-std-source branch from 5b0b080 to d4d1fbc Compare October 9, 2026 10:49

xizheyin force-pushed the show-std-source branch from d4d1fbc to 3940850 Compare October 9, 2026 10:55

rust-bors Bot 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 Oct 9, 2026

estebank mentioned this pull request Oct 9, 2026

Fix suggestions pointing into macro declaration exposed by #144585 #164044

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JonathanBrouwer mentioned this pull request Oct 9, 2026

Rollup of 10 pull requests #164048

Closed

rust-bors Bot 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 Oct 9, 2026

show span-only suggestions when source is unavailable in ui tests

57d9695

xizheyin force-pushed the show-std-source branch from 3940850 to 57d9695 Compare October 9, 2026 19:12

xizheyin commented Oct 9, 2026

View reviewed changes

jieyouxu self-assigned this Oct 10, 2026

		show_suggestions_with_unavailable_source: bool = (false, parse_bool, [UNTRACKED],
		"show span-only suggestions when the source code is unavailable"),

		help: check for equality instead of pattern matching
		--> $SRC_DIR/alloc/src/macros.rs:LL:COL

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