could not find markdown in source in cargo doc from comments in proc macro

[ids1024]

Invoking this proc macro and running cargo doc rusults in a crash the the error could not find markdown in source:

#[proc_macro]
pub fn foo(_: TokenStream) -> TokenStream {
    "/// https://foobar.com\npub struct Foo;".parse().unwrap()
}

If this code were written directly rather than generated by a proc macro, this would produce warning: this URL is not a hyperlink. But I guess when it goes through a proc macro it can't generate correct span information for the warning and crashes.

I originally noticed this with the schemafy::schemafy! macro.

Meta

rustc --version --verbose:

rustc 1.60.0-nightly (89b9f7b28 2022-01-10)

Backtrace

thread 'rustc' panicked at 'could not find markdown in source', src/librustdoc/passes/mod.rs:181:48
stack backtrace:
   0: rust_begin_unwind
             at /rustc/89b9f7b284aacc5f8613438b80e4dd7bdd10549e/library/std/src/panicking.rs:498:5
   1: core::panicking::panic_fmt
             at /rustc/89b9f7b284aacc5f8613438b80e4dd7bdd10549e/library/core/src/panicking.rs:110:14
   2: core::panicking::panic_display
             at /rustc/89b9f7b284aacc5f8613438b80e4dd7bdd10549e/library/core/src/panicking.rs:65:5
   3: core::panicking::panic_str
             at /rustc/89b9f7b284aacc5f8613438b80e4dd7bdd10549e/library/core/src/panicking.rs:56:5
   4: core::option::expect_failed
             at /rustc/89b9f7b284aacc5f8613438b80e4dd7bdd10549e/library/core/src/option.rs:1817:5
   5: rustdoc::passes::source_span_for_markdown_range
   6: <rustdoc::passes::bare_urls::BareUrlsLinter as rustdoc::visit::DocVisitor>::visit_item
   7: <rustdoc::passes::bare_urls::BareUrlsLinter as rustdoc::visit::DocVisitor>::visit_inner_recur
   8: <rustdoc::passes::bare_urls::BareUrlsLinter as rustdoc::visit::DocVisitor>::visit_item
   9: rustdoc::passes::bare_urls::check_bare_urls
  10: <rustc_session::session::Session>::time::<rustdoc::clean::types::Crate, rustdoc::core::run_global_ctxt::{closure#8}>
  11: rustdoc::core::run_global_ctxt
  12: <rustc_session::session::Session>::time::<(rustdoc::clean::types::Crate, rustdoc::config::RenderOptions, rustdoc::formats::cache::Cache), rustdoc::main_options::{closure#0}::{closure#0}::{closure#1}::{closure#0}>
  13: <rustc_interface::passes::QueryContext>::enter::<rustdoc::main_options::{closure#0}::{closure#0}::{closure#1}, core::result::Result<(), rustc_errors::ErrorReported>>
  14: <rustc_interface::interface::Compiler>::enter::<rustdoc::main_options::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
  15: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorReported>, rustdoc::main_options::{closure#0}>::{closure#1}>
  16: rustc_interface::interface::create_compiler_and_run::<core::result::Result<(), rustc_errors::ErrorReported>, rustdoc::main_options::{closure#0}>
  17: rustdoc::main_options
  18: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals<rustdoc::main_args::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

error: Unrecognized option: 'crate-version'

error: could not document `proc-macro-bug`

Caused by:
  process didn't exit successfully: `rustdoc --edition=2021 --crate-type lib --crate-name proc_macro_bug src/lib.rs -o /home/ian/src/proc-macro-bug/target/doc --error-format=json --json=diagnostic-rendered-ansi,future-incompat -C metadata=f8594ed8329b26d0 -L dependency=/home/ian/src/proc-macro-bug/target/debug/deps --extern macros=/home/ian/src/proc-macro-bug/target/debug/deps/libmacros-4807c026ed1d48b2.so --crate-version 0.1.0` (exit status: 1)

[toksdotdev]

Were you able to resolve this? Also ran into a similar issue when using the schemafy proc maco.

[ids1024]

I couldn't seem to work around it by adding an #[allow], so I've just edited the schema file.

[GuillaumeGomez]

I have a fix for this issue in #94478.