fix off-by-one error

3 files changed, 77 insertions, 6 deletions

diff --git a/src/tools/rust-analyzer/.github/workflows/ci.yaml b/src/tools/rust-analyzer/.github/workflows/ci.yaml
index ec33009239c..81b55712d7f 100644
--- a/src/tools/rust-analyzer/.github/workflows/ci.yaml
+++ b/src/tools/rust-analyzer/.github/workflows/ci.yaml
@@ -64,7 +64,11 @@ jobs:
         run: |
           rustup update --no-self-update ${{ env.RUST_CHANNEL }}
           rustup default ${{ env.RUST_CHANNEL }}
-          rustup component add --toolchain ${{ env.RUST_CHANNEL }} rustfmt rust-src
+          rustup component add --toolchain ${{ env.RUST_CHANNEL }} rust-src
+          # We always use a nightly rustfmt, regardless of channel, because we need
+          # --file-lines.
+          rustup toolchain add nightly --profile minimal
+          rustup component add --toolchain nightly rustfmt
       # https://github.com/actions-rust-lang/setup-rust-toolchain/blob/main/rust.json
       - name: Install Rust Problem Matcher
         if: matrix.os == 'ubuntu-latest'
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers/request.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers/request.rs
index ed028f1d37b..37e4a4940ba 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers/request.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/handlers/request.rs
@@ -2284,7 +2284,8 @@ fn run_rustfmt(
                 cmd.arg(
                     json!([{
                         "file": "stdin",
-                        "range": [start_line, end_line]
+                        // LineCol is 0-based, but rustfmt is 1-based.
+                        "range": [start_line + 1, end_line + 1]
                     }])
                     .to_string(),
                 );
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
index 2b3c0a47a22..7f95641746e 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
@@ -21,12 +21,14 @@ use lsp_types::{
     notification::DidOpenTextDocument,
     request::{
         CodeActionRequest, Completion, Formatting, GotoTypeDefinition, HoverRequest,
-        InlayHintRequest, InlayHintResolveRequest, WillRenameFiles, WorkspaceSymbolRequest,
+        InlayHintRequest, InlayHintResolveRequest, RangeFormatting, WillRenameFiles,
+        WorkspaceSymbolRequest,
     },
     CodeActionContext, CodeActionParams, CompletionParams, DidOpenTextDocumentParams,
-    DocumentFormattingParams, FileRename, FormattingOptions, GotoDefinitionParams, HoverParams,
-    InlayHint, InlayHintLabel, InlayHintParams, PartialResultParams, Position, Range,
-    RenameFilesParams, TextDocumentItem, TextDocumentPositionParams, WorkDoneProgressParams,
+    DocumentFormattingParams, DocumentRangeFormattingParams, FileRename, FormattingOptions,
+    GotoDefinitionParams, HoverParams, InlayHint, InlayHintLabel, InlayHintParams,
+    PartialResultParams, Position, Range, RenameFilesParams, TextDocumentItem,
+    TextDocumentPositionParams, WorkDoneProgressParams,
 };
 use rust_analyzer::lsp::ext::{OnEnter, Runnables, RunnablesParams};
 use serde_json::json;
@@ -661,6 +663,70 @@ fn main() {}
 }
 
 #[test]
+fn test_format_document_range() {
+    if skip_slow_tests() {
+        return;
+    }
+
+    let server = Project::with_fixture(
+        r#"
+//- /Cargo.toml
+[package]
+name = "foo"
+version = "0.0.0"
+
+//- /src/lib.rs
+fn main() {
+    let unit_offsets_cache = collect(dwarf.units  ())  ?;
+}
+"#,
+    )
+    .with_config(serde_json::json!({
+        "rustfmt": {
+            "overrideCommand": [ "rustfmt", "+nightly", ],
+            "rangeFormatting": { "enable": true }
+        },
+    }))
+    .server()
+    .wait_until_workspace_is_loaded();
+
+    server.request::<RangeFormatting>(
+        DocumentRangeFormattingParams {
+            range: Range {
+                end: Position { line: 1, character: 0 },
+                start: Position { line: 1, character: 0 },
+            },
+            text_document: server.doc_id("src/lib.rs"),
+            options: FormattingOptions {
+                tab_size: 4,
+                insert_spaces: false,
+                insert_final_newline: None,
+                trim_final_newlines: None,
+                trim_trailing_whitespace: None,
+                properties: HashMap::new(),
+            },
+            work_done_progress_params: WorkDoneProgressParams::default(),
+        },
+        json!([
+            {
+                "newText": "",
+                "range": {
+                    "start": { "character": 48, "line": 1 },
+                    "end": { "character": 50, "line": 1 },
+                },
+            },
+            {
+                "newText": "",
+                "range": {
+                    "start": { "character": 53, "line": 1 },
+                    "end": { "character": 55, "line": 1 },
+                },
+            }
+        ]),
+    );
+}
+
+#[test]
 fn test_missing_module_code_action() {
     if skip_slow_tests() {
         return;