ICE having include! in code from stdin when calling rustc

[andjo403]

to reproduce the fault this can be used:
echo 'include!("auxiliary/empty.rs"); pub fn main(){}' | rustc -

will result in this ICE:

thread 'rustc' panicked at 'cannot resolve relative path in non-file source ', src/libsyntax/ext/source_util.rs:189:22 note: Run with RUST_BACKTRACE=1 environment variable to display a backtrace. error: internal compiler error: unexpected panic note: the compiler unexpectedly panicked. this is a bug. note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports note: rustc 1.36.0 (a53f9df 2019-07-03) running on x86_64-unknown-linux-gnu

the question is what is the path that shall be used when the code is from stdin maybe some temp file name in the currrent working dir.

[mystor]

This ICE also occurs when using include_bytes! and include_str!, which makes sense as they use the same mechanism under the hood (include, include_str, include_bytes). The mechanism is also used by #[doc(include="x")], meaning it also ICEs.

$ echo 'include_str!("x");' | rustc -
thread 'rustc' panicked at 'cannot resolve relative path in non-file source `<anon>`'
$ echo 'include_bytes!("x");' | rustc -
thread 'rustc' panicked at 'cannot resolve relative path in non-file source `<anon>`'
$ echo '#![feature(external_doc)] #![doc(include="x")]' | rustc -
thread 'rustc' panicked at 'cannot resolve relative path in non-file source `<anon>`'

[mystor]

While poking at this I also noticed that mod foo; items are silently ignored, and filed #65601.