Skip to content

Remove incorrect assert #79976

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
bors merged 1 commit into from
Dec 13, 2020
Merged

Remove incorrect assert #79976

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion src/librustdoc/passes/collect_intra_doc_links.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -436,8 +436,8 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
// Try looking for methods and associated items.
let mut split = path_str.rsplitn(2, "::");
// NB: `split`'s first element is always defined, even if the delimiter was not present.
// NB: `item_str` could be empty when resolving in the root namespace (e.g. `::std`).
Copy link
Contributor

@Eric-Arellano Eric-Arellano Dec 12, 2020

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Oh wait, I'm confused. Note that rsplit returns a reverse iterator. In this example, I think the first element would be std, right? It would not be empty.

Copy link
Member Author

@jyn514 jyn514 Dec 12, 2020

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Here's the debug output from the assertion failure on hyper:

TRACE rustdoc::passes::collect_intra_doc_links considering link '::client'
DEBUG rustdoc::passes::collect_intra_doc_links resolving ::client as a macro in the module DefId(0:248 ~ hyper[8787]::body)
DEBUG rustdoc::passes::collect_intra_doc_links ::client resolved to Err(()) in namespace TypeNS
DEBUG rustdoc::passes::collect_intra_doc_links  resolved to Err(()) in namespace TypeNS
DEBUG rustdoc::passes::collect_intra_doc_links ::client resolved to Err(()) in namespace ValueNS
DEBUG rustdoc::passes::collect_intra_doc_links  resolved to Err(()) in namespace TypeNS
DEBUG rustdoc::passes::collect_intra_doc_links looking for enum variant ::client
DEBUG rustdoc::passes::collect_intra_doc_links  resolved to Err(()) in namespace TypeNS
thread 'rustc' panicked at 'assertion failed: !item_str.is_empty()', src/librustdoc/passes/collect_intra_doc_links.rs:439:9

So I think what's going wrong is that resolve_variant calls resolve recursively, and on the second call the string is empty (and only has one item in the iterator). This could probably be improved but it would require a redesign of the algorithm.

Copy link
Member Author

@jyn514 jyn514 Dec 12, 2020 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yup, this is the backtrace:

   0: std::panicking::begin_panic
             at /home/joshua/rustc/library/std/src/panicking.rs:519:12
   1: rustdoc::passes::collect_intra_doc_links::LinkCollector::resolve
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:439:9
   2: rustdoc::passes::collect_intra_doc_links::LinkCollector::check_full_res
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:637:17
   3: rustdoc::passes::collect_intra_doc_links::resolution_failure::{{closure}}
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1680:33
   4: rustdoc::passes::collect_intra_doc_links::report_diagnostic::{{closure}}
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1597:9
   5: core::ops::function::FnOnce::call_once{{vtable.shim}}
             at /home/joshua/rustc/library/core/src/ops/function.rs:227:5
   6: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
             at /home/joshua/rustc/library/alloc/src/boxed.rs:1328:9
   7: rustc_middle::lint::struct_lint_level::struct_lint_level_impl
             at /home/joshua/rustc/compiler/rustc_middle/src/lint.rs:362:9
   8: rustc_middle::lint::struct_lint_level
             at /home/joshua/rustc/compiler/rustc_middle/src/lint.rs:364:5
   9: rustc_middle::ty::context::TyCtxt::struct_span_lint_hir
             at /home/joshua/rustc/compiler/rustc_middle/src/ty/context.rs:2562:9
  10: rustdoc::passes::collect_intra_doc_links::report_diagnostic
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1567:5
  11: rustdoc::passes::collect_intra_doc_links::resolution_failure
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1617:5
  12: rustdoc::passes::collect_intra_doc_links::LinkCollector::resolve_with_disambiguator
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1299:21
  13: rustdoc::passes::collect_intra_doc_links::LinkCollector::resolve_link
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:1082:39
  14: <rustdoc::passes::collect_intra_doc_links::LinkCollector as rustdoc::fold::DocFolder>::fold_item
             at /home/joshua/rustc/src/librustdoc/passes/collect_intra_doc_links.rs:909:28

Notice this is in diagnostics, not the main resole code.

let item_str = split.next().unwrap();
assert!(!item_str.is_empty());
let item_name = Symbol::intern(item_str);
let path_root = split
.next()
Expand Down