Test sources require filesystems with case-sensitiveness #6734
Description
I ran
$ git clone git@github.com:rust-lang/rustfmt.gitwarning: the following paths have collided (e.g. case-sensitive paths on a case-insensitive filesystem) and only one from the same colliding group is in the working tree: 'tests/source/reorder_modules/ABCD/mod.rs' 'tests/source/reorder_modules/abcd/mod.rs' 'tests/source/reorder_modules/ZYXW/mod.rs' 'tests/source/reorder_modules/zyxw/mod.rs' 'tests/target/reorder_modules/ABCD/mod.rs' 'tests/target/reorder_modules/abcd/mod.rs' 'tests/target/reorder_modules/ZYXW/mod.rs' 'tests/target/reorder_modules/zyxw/mod.rs' I guess this is fine, if we require that the test sources be only run under a case-sensitive filesystem? 🤷