force-warns panics with unknown lint name

[ehuss]

Using the --force-warns option with an unknown lint name causes an ICE.

rustc +nightly --force-warns=abc -Zunstable-options foo.rs

I expected to see this happen: Issue a E0602 error.

Meta

rustc --version --verbose:

rustc 1.55.0-nightly (885399992 2021-07-06)
binary: rustc
commit-hash: 885399992c4c1dde37b506b8507a7d69415646b9
commit-date: 2021-07-06
host: x86_64-apple-darwin
release: 1.55.0-nightly
LLVM version: 12.0.1

Backtrace

thread 'rustc' panicked at 'compiler/rustc_lint/src/levels.rs:117:37: A valid lint failed to produce a lint ids', compiler/rustc_middle/src/util/bug.rs:35:26
stack backtrace:
   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_middle::util::bug::opt_span_bug_fmt::{{closure}}
   3: rustc_middle::ty::context::tls::with_opt::{{closure}}
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_lint::levels::LintLevelsBuilder::process_command_line::{{closure}}
   8: rustc_lint::levels::LintLevelsBuilder::new
   9: rustc_lint::context::EarlyContext::new
  10: rustc_lint::early::check_ast_crate
  11: rustc_interface::passes::pre_expansion_lint
  12: rustc_interface::passes::configure_and_expand
  13: rustc_interface::queries::Queries::expansion
  14: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  15: rustc_span::with_source_map
  16: rustc_interface::interface::create_compiler_and_run
  17: scoped_tls::ScopedKey<T>::set

cc @rylev

[inquisitivecrystal]

@rustbot claim

I'm going to take a look at this. I'm also going to see if I can fix the problem you mentioned at #86009 (comment) while I'm at it.

[ehuss]

Just FYI, the cap-lints issue has been fixed by #86572.

[inquisitivecrystal]

Good to know!