-Z location-detail: provide option to disable all location details

[hudson-ayers]

As reported here, when I first implemented the -Z location-detail flag there was a bug, where passing an empty list was not correctly supported, and instead rejected by the compiler. This PR fixes that such that passing an empty list results in no location details being tracked, as originally specified in rust-lang/rfcs#2091 .

This PR also adds a test case to verify that this option continues to work as intended.

[rust-highfive]

r? @GuillaumeGomez

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[GuillaumeGomez]

I'm not the right reviewer for this change.

r? @davidtwco

[Aaron1011]

Personally, I think it might be more intuitive to have an explicit none or no option (which would be incompatible with all other options).

[davidtwco]

I agree with @Aaron1011, I'd prefer to see this with a none or no option than accepting an empty list. As far as I can gather from skimming the parse functions, we don't have any other options that accept an empty list, but we do have some that accept none/no.

[hudson-ayers]

Updated to support none instead of an empty list

[klensy]

Should be fixed also there (but i don't see where it used)

rust/compiler/rustc_session/src/options.rs

Lines 397 to 398 in c9b3183

	pub const parse_location_detail: &str =
	"comma separated list of location details to track: `file`, `line`, or `column`";

and there

rust/compiler/rustc_session/src/options.rs

Lines 1349 to 1351 in c9b3183

	location_detail: LocationDetail = (LocationDetail::all(), parse_location_detail, [TRACKED],
	"comma separated list of location details to be tracked when using caller_location \
	valid options are `file`, `line`, and `column` (default: all)"),

Should all (or added as valid one) option be reworded? As if all passed as argument, it isn't accepted.

[hudson-ayers]

Should be fixed also there (but i don't see where it used)

rust/compiler/rustc_session/src/options.rs

Lines 397 to 398 in c9b3183

	pub const parse_location_detail: &str =
	"comma separated list of location details to track: `file`, `line`, or `column`";

Fixed. And I agree it is confusing to see where this constant is used -- the key is that the options!() macro has an implicit requirement that you pass as $parse a name which is both the name of the function that parses the option in the parse module and also the name of the options descriptor string in the desc module. So this is used here: https://github.com/rust-lang/rust/blob/6e89c4cfb1c76a56ee70d19af6ce1070d4bd7cec/compiler/rustc_session/src/options.rs#L1364

and there

rust/compiler/rustc_session/src/options.rs

Lines 1349 to 1351 in c9b3183

	location_detail: LocationDetail = (LocationDetail::all(), parse_location_detail, [TRACKED],
	"comma separated list of location details to be tracked when using caller_location \
	valid options are `file`, `line`, and `column` (default: all)"),

Should all (or added as valid one) option be reworded? As if all passed as argument, it isn't accepted.

I removed any mention of all and specified that the default is file,line,column.

[davidtwco]

@bors r+

[bors]

📌 Commit 6dea21a has been approved by davidtwco

It is now in the queue for this repository.