rustc overwrites input file when it has no extension

[comex]

% echo 'fn main() {}' > test
% rustc test
% ./test # input has been replaced with the output binary

Tested on OS X, af93684. Not that it makes sense to write Rust files with no extension, but if you do, rustc should not overwrite the input file by default.

[SiegeLord]

If/when #9826 gets implemented, it'll make sense to have an extension-less Rust file. I'm not sure where rustc --run would place the compilation output, however, so it might not hit this specific bug.

[pongad]

Will simply failing if the input file has no extension fix the issue? rustc --run can probably put the compilation output in a tmp file somewhere right?

[steveklabnik]

Triage: this still happens today.

[frewsxcv]

This still happens

coreyf@frewbook-pro /tmp> cat hi
fn main() {}
coreyf@frewbook-pro /tmp> file hi
hi: ASCII text
coreyf@frewbook-pro /tmp> rustc hi
coreyf@frewbook-pro /tmp> file hi
hi: Mach-O 64-bit executable x86_64