Merge #8767

8767: implement range formatting r=matklad a=euclio

Fixes #7580.

This PR implements the `textDocument/rangeFormatting` request using `rustfmt`'s `--file-lines` option.

Still needs some tests. What I want to know is how I should handle the instability of the `--file-lines` option. It's still unstable in rustfmt, so it's only available on nightly, and needs a special flag to enable. Is there a way for `rust-analyzer` to detect if it's using nightly rustfmt, or for users to opt-in?

Co-authored-by: Andy Russell <[email protected]>

1 files changed, 7 insertions, 0 deletions

diff --git a/docs/user/generated_config.adoc b/docs/user/generated_config.adoc
index c02bab7cc..f3da82feb 100644
--- a/docs/user/generated_config.adoc
+++ b/docs/user/generated_config.adoc
@@ -346,6 +346,13 @@ Additional arguments to `rustfmt`.
 Advanced option, fully override the command rust-analyzer uses for
 formatting.
 --
+[[rust-analyzer.rustfmt.enableRangeFormatting]]rust-analyzer.rustfmt.enableRangeFormatting (default: `false`)::
++
+--
+Enables the use of rustfmt's unstable range formatting command for the
+`textDocument/rangeFormatting` request. The rustfmt option is unstable and only
+available on a nightly build.
+--
 [[rust-analyzer.workspace.symbol.search.scope]]rust-analyzer.workspace.symbol.search.scope (default: `"workspace"`)::
 +
 --