Using include! with filename ending in '>' causes failed assertion in libspan

[LunarLambda]

Code

Requirement:
Create an empty file called '>', i.e. using touch '>'

include!(">");

Meta

rustc --version --verbose:

rustc 1.43.1 (8d69840ab 2020-05-04)
binary: rustc
commit-hash: 8d69840ab92ea7f4d323420088dd8c9775f180cd
commit-date: 2020-05-04
host: x86_64-unknown-linux-gnu
release: 1.43.1
LLVM version: 9.0

Error output

thread 'rustc' panicked at 'assertion failed: !p.to_string_lossy().ends_with('>')', src/librustc_span/lib.rs:125:9

error: internal compiler error: unexpected panic

Backtrace

stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1063
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1426
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:204
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:224
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:474
  12: std::panicking::begin_panic
  13: <rustc_span::FileName as core::convert::From<std::path::PathBuf>>::from
  14: rustc_span::source_map::SourceMap::load_file
  15: rustc_parse::try_file_to_source_file
  16: rustc_parse::new_sub_parser_from_file
  17: rustc_builtin_macros::source_util::expand_include
  18: <F as rustc_expand::base::TTMacroExpander>::expand
  19: rustc_expand::expand::MacroExpander::fully_expand_fragment
  20: rustc_expand::expand::MacroExpander::expand_crate
  21: rustc_session::utils::<impl rustc_session::session::Session>::time
  22: rustc_interface::passes::configure_and_expand_inner
  23: rustc_interface::passes::configure_and_expand::{{closure}}
  24: rustc_data_structures::box_region::PinnedGenerator<I,A,R>::new
  25: rustc_interface::passes::configure_and_expand
  26: rustc_interface::queries::Queries::expansion
  27: rustc_interface::interface::run_compiler_in_existing_thread_pool
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[eddyb]

Hmm, we should only disallow <...> (since that's what we use for non-real "files") although I guess </> or even just <foo> might be a valid path itself?

Internally we can tell apart between the two, I'm guessing this is to avoid tools seeing something with < or > in it and misinterpreting it as not a real file? But in that case we'd want a real error not an assert.

cc @ehuss

[Dylan-DPC-zz]

Marked as p-medium based on the discussion on the prioritization thread

[Enselic]

PR with fix: #115304