ICE with rustdoc JSON backend and duplicated exports

[sunshowers]

Hi there --

Looks like the rustdoc json output seems to have an issue with duplicated exports. I hit this issue with https://docs.rs/ansi_term/0.12.1/ansi_term/index.html, which exports both Color and Colour as the same type.

Code

Minimized example:

mod inner {
    pub struct Public;
}
pub use inner::Public as NewName1;
pub use inner::Public as NewName2;

Reproduces with the following command:

RUSTDOCFLAGS='--output-format json' cargo +nightly doc

Meta

rustc --version --verbose:

rustc 1.57.0-nightly (5b210643e 2021-10-11)
binary: rustc
commit-hash: 5b210643ebf2485aafdf2494de8cf41941a64e95
commit-date: 2021-10-11
host: x86_64-unknown-linux-gnu
release: 1.57.0-nightly
LLVM version: 13.0.0

Error output

thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Item { id: Id("0:4"), crate_id: 0, name: Some("NewName1"), span: Some(Span { filename: "src/lib.rs", begin: (2, 4), end: (2, 22) }), visibility: Public, docs: None, links: {}, attrs: [], deprecation: None, inner: Struct(Struct { struct_type: Unit, generics: Generics { params: [], where_predicates: [] }, fields_stripped: false, fields: [], impls: [Id("a:2:2989-0:4"), Id("a:2:3001-0:4"), Id("a:2:3030-0:4"), Id("a:2:8303-0:4"), Id("a:2:8304-0:4"), Id("b:2:2922-0:4"), Id("b:2:2918-0:4"), Id("b:2:2933-0:4"), Id("b:2:2928-0:4"), Id("b:2:2594-0:4"), Id("b:2:2597-0:4"), Id("b:2:3652-0:4")] }) }`,
 right: `Item { id: Id("0:4"), crate_id: 0, name: Some("NewName2"), span: Some(Span { filename: "src/lib.rs", begin: (2, 4), end: (2, 22) }), visibility: Public, docs: None, links: {}, attrs: [], deprecation: None, inner: Struct(Struct { struct_type: Unit, generics: Generics { params: [], where_predicates: [] }, fields_stripped: false, fields: [], impls: [Id("a:2:2989-0:4"), Id("a:2:3001-0:4"), Id("a:2:3030-0:4"), Id("a:2:8303-0:4"), Id("a:2:8304-0:4"), Id("b:2:2922-0:4"), Id("b:2:2918-0:4"), Id("b:2:2933-0:4"), Id("b:2:2928-0:4"), Id("b:2:2594-0:4"), Id("b:2:2597-0:4"), Id("b:2:3652-0:4")] }) }`', src/librustdoc/json/mod.rs:195:17

Backtrace

   0: rust_begin_unwind
             at /rustc/5b210643ebf2485aafdf2494de8cf41941a64e95/library/std/src/panicking.rs:517:5
   1: core::panicking::panic_fmt
             at /rustc/5b210643ebf2485aafdf2494de8cf41941a64e95/library/core/src/panicking.rs:100:14
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed
   4: <rustdoc::json::JsonRenderer as rustdoc::formats::renderer::FormatRenderer>::item
   5: <rustdoc::json::JsonRenderer as rustdoc::formats::renderer::FormatRenderer>::item
   6: rustdoc::formats::renderer::run_format
   7: rustc_session::utils::<impl rustc_session::session::Session>::time
   8: rustc_interface::passes::QueryContext::enter
   9: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  10: rustc_span::with_source_map
  11: rustc_interface::interface::create_compiler_and_run
  12: rustdoc::main_options
  13: scoped_tls::ScopedKey<T>::set

I spent a little time looking at this, and it looks like changing mod inner to pub mod inner also fails with jsondocck:

thread 'main' panicked at 'Name collision: import_id is duplicated', src/tools/jsondocck/src/main.rs:274:21
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

so it's likely that the handling of duplicate public re-exports is also broken.

[sunshowers]

This might be related to #89097 though it seems different at first glance.

[jyn514]

Duplicate of #83720.