1 files changed, 592 insertions, 0 deletions

diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
new file mode 100644
index 000000000..4500d4982
--- /dev/null
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -0,0 +1,592 @@
+//! Conversion of rust-analyzer specific types to lsp_types equivalents.
+use ra_db::{FileId, FileRange};
+use ra_ide::{
+    translate_offset_with_edit, Assist, CompletionItem, CompletionItemKind, Documentation,
+    FileSystemEdit, Fold, FoldKind, FunctionSignature, Highlight, HighlightModifier, HighlightTag,
+    HighlightedRange, InlayHint, InlayKind, InsertTextFormat, LineIndex, NavigationTarget,
+    ReferenceAccess, Severity, SourceChange, SourceFileEdit,
+};
+use ra_syntax::{SyntaxKind, TextRange, TextSize};
+use ra_text_edit::{Indel, TextEdit};
+use ra_vfs::LineEndings;
+
+use crate::{lsp_ext, semantic_tokens, world::WorldSnapshot, Result};
+
+pub(crate) fn position(line_index: &LineIndex, offset: TextSize) -> lsp_types::Position {
+    let line_col = line_index.line_col(offset);
+    let line = u64::from(line_col.line);
+    let character = u64::from(line_col.col_utf16);
+    lsp_types::Position::new(line, character)
+}
+
+pub(crate) fn range(line_index: &LineIndex, range: TextRange) -> lsp_types::Range {
+    let start = position(line_index, range.start());
+    let end = position(line_index, range.end());
+    lsp_types::Range::new(start, end)
+}
+
+pub(crate) fn symbol_kind(syntax_kind: SyntaxKind) -> lsp_types::SymbolKind {
+    match syntax_kind {
+        SyntaxKind::FN_DEF => lsp_types::SymbolKind::Function,
+        SyntaxKind::STRUCT_DEF => lsp_types::SymbolKind::Struct,
+        SyntaxKind::ENUM_DEF => lsp_types::SymbolKind::Enum,
+        SyntaxKind::ENUM_VARIANT => lsp_types::SymbolKind::EnumMember,
+        SyntaxKind::TRAIT_DEF => lsp_types::SymbolKind::Interface,
+        SyntaxKind::MACRO_CALL => lsp_types::SymbolKind::Function,
+        SyntaxKind::MODULE => lsp_types::SymbolKind::Module,
+        SyntaxKind::TYPE_ALIAS_DEF => lsp_types::SymbolKind::TypeParameter,
+        SyntaxKind::RECORD_FIELD_DEF => lsp_types::SymbolKind::Field,
+        SyntaxKind::STATIC_DEF => lsp_types::SymbolKind::Constant,
+        SyntaxKind::CONST_DEF => lsp_types::SymbolKind::Constant,
+        SyntaxKind::IMPL_DEF => lsp_types::SymbolKind::Object,
+        _ => lsp_types::SymbolKind::Variable,
+    }
+}
+
+pub(crate) fn document_highlight_kind(
+    reference_access: ReferenceAccess,
+) -> lsp_types::DocumentHighlightKind {
+    match reference_access {
+        ReferenceAccess::Read => lsp_types::DocumentHighlightKind::Read,
+        ReferenceAccess::Write => lsp_types::DocumentHighlightKind::Write,
+    }
+}
+
+pub(crate) fn diagnostic_severity(severity: Severity) -> lsp_types::DiagnosticSeverity {
+    match severity {
+        Severity::Error => lsp_types::DiagnosticSeverity::Error,
+        Severity::WeakWarning => lsp_types::DiagnosticSeverity::Hint,
+    }
+}
+
+pub(crate) fn documentation(documentation: Documentation) -> lsp_types::Documentation {
+    let value = crate::markdown::format_docs(documentation.as_str());
+    let markup_content = lsp_types::MarkupContent { kind: lsp_types::MarkupKind::Markdown, value };
+    lsp_types::Documentation::MarkupContent(markup_content)
+}
+
+pub(crate) fn insert_text_format(
+    insert_text_format: InsertTextFormat,
+) -> lsp_types::InsertTextFormat {
+    match insert_text_format {
+        InsertTextFormat::Snippet => lsp_types::InsertTextFormat::Snippet,
+        InsertTextFormat::PlainText => lsp_types::InsertTextFormat::PlainText,
+    }
+}
+
+pub(crate) fn completion_item_kind(
+    completion_item_kind: CompletionItemKind,
+) -> lsp_types::CompletionItemKind {
+    match completion_item_kind {
+        CompletionItemKind::Keyword => lsp_types::CompletionItemKind::Keyword,
+        CompletionItemKind::Snippet => lsp_types::CompletionItemKind::Snippet,
+        CompletionItemKind::Module => lsp_types::CompletionItemKind::Module,
+        CompletionItemKind::Function => lsp_types::CompletionItemKind::Function,
+        CompletionItemKind::Struct => lsp_types::CompletionItemKind::Struct,
+        CompletionItemKind::Enum => lsp_types::CompletionItemKind::Enum,
+        CompletionItemKind::EnumVariant => lsp_types::CompletionItemKind::EnumMember,
+        CompletionItemKind::BuiltinType => lsp_types::CompletionItemKind::Struct,
+        CompletionItemKind::Binding => lsp_types::CompletionItemKind::Variable,
+        CompletionItemKind::Field => lsp_types::CompletionItemKind::Field,
+        CompletionItemKind::Trait => lsp_types::CompletionItemKind::Interface,
+        CompletionItemKind::TypeAlias => lsp_types::CompletionItemKind::Struct,
+        CompletionItemKind::Const => lsp_types::CompletionItemKind::Constant,
+        CompletionItemKind::Static => lsp_types::CompletionItemKind::Value,
+        CompletionItemKind::Method => lsp_types::CompletionItemKind::Method,
+        CompletionItemKind::TypeParam => lsp_types::CompletionItemKind::TypeParameter,
+        CompletionItemKind::Macro => lsp_types::CompletionItemKind::Method,
+        CompletionItemKind::Attribute => lsp_types::CompletionItemKind::EnumMember,
+    }
+}
+
+pub(crate) fn text_edit(
+    line_index: &LineIndex,
+    line_endings: LineEndings,
+    indel: Indel,
+) -> lsp_types::TextEdit {
+    let range = range(line_index, indel.delete);
+    let new_text = match line_endings {
+        LineEndings::Unix => indel.insert,
+        LineEndings::Dos => indel.insert.replace('\n', "\r\n"),
+    };
+    lsp_types::TextEdit { range, new_text }
+}
+
+pub(crate) fn text_edit_vec(
+    line_index: &LineIndex,
+    line_endings: LineEndings,
+    text_edit: TextEdit,
+) -> Vec<lsp_types::TextEdit> {
+    text_edit
+        .as_indels()
+        .iter()
+        .map(|it| self::text_edit(line_index, line_endings, it.clone()))
+        .collect()
+}
+
+pub(crate) fn completion_item(
+    line_index: &LineIndex,
+    line_endings: LineEndings,
+    completion_item: CompletionItem,
+) -> lsp_types::CompletionItem {
+    let mut additional_text_edits = Vec::new();
+    let mut text_edit = None;
+    // LSP does not allow arbitrary edits in completion, so we have to do a
+    // non-trivial mapping here.
+    let source_range = completion_item.source_range();
+    for indel in completion_item.text_edit().as_indels() {
+        if indel.delete.contains_range(source_range) {
+            text_edit = Some(if indel.delete == source_range {
+                self::text_edit(line_index, line_endings, indel.clone())
+            } else {
+                assert!(source_range.end() == indel.delete.end());
+                let range1 = TextRange::new(indel.delete.start(), source_range.start());
+                let range2 = source_range;
+                let indel1 = Indel::replace(range1, String::new());
+                let indel2 = Indel::replace(range2, indel.insert.clone());
+                additional_text_edits.push(self::text_edit(line_index, line_endings, indel1));
+                self::text_edit(line_index, line_endings, indel2)
+            })
+        } else {
+            assert!(source_range.intersect(indel.delete).is_none());
+            let text_edit = self::text_edit(line_index, line_endings, indel.clone());
+            additional_text_edits.push(text_edit);
+        }
+    }
+    let text_edit = text_edit.unwrap();
+
+    let mut res = lsp_types::CompletionItem {
+        label: completion_item.label().to_string(),
+        detail: completion_item.detail().map(|it| it.to_string()),
+        filter_text: Some(completion_item.lookup().to_string()),
+        kind: completion_item.kind().map(completion_item_kind),
+        text_edit: Some(text_edit.into()),
+        additional_text_edits: Some(additional_text_edits),
+        documentation: completion_item.documentation().map(documentation),
+        deprecated: Some(completion_item.deprecated()),
+        command: if completion_item.trigger_call_info() {
+            let cmd = lsp_types::Command {
+                title: "triggerParameterHints".into(),
+                command: "editor.action.triggerParameterHints".into(),
+                arguments: None,
+            };
+            Some(cmd)
+        } else {
+            None
+        },
+        ..Default::default()
+    };
+
+    if completion_item.score().is_some() {
+        res.preselect = Some(true)
+    }
+
+    if completion_item.deprecated() {
+        res.tags = Some(vec![lsp_types::CompletionItemTag::Deprecated])
+    }
+
+    res.insert_text_format = Some(insert_text_format(completion_item.insert_text_format()));
+
+    res
+}
+
+pub(crate) fn signature_information(
+    signature: FunctionSignature,
+    concise: bool,
+) -> lsp_types::SignatureInformation {
+    let (label, documentation, params) = if concise {
+        let mut params = signature.parameters;
+        if signature.has_self_param {
+            params.remove(0);
+        }
+        (params.join(", "), None, params)
+    } else {
+        (signature.to_string(), signature.doc.map(documentation), signature.parameters)
+    };
+
+    let parameters: Vec<lsp_types::ParameterInformation> = params
+        .into_iter()
+        .map(|param| lsp_types::ParameterInformation {
+            label: lsp_types::ParameterLabel::Simple(param),
+            documentation: None,
+        })
+        .collect();
+
+    lsp_types::SignatureInformation { label, documentation, parameters: Some(parameters) }
+}
+
+pub(crate) fn inlay_int(line_index: &LineIndex, inlay_hint: InlayHint) -> lsp_ext::InlayHint {
+    lsp_ext::InlayHint {
+        label: inlay_hint.label.to_string(),
+        range: range(line_index, inlay_hint.range),
+        kind: match inlay_hint.kind {
+            InlayKind::ParameterHint => lsp_ext::InlayKind::ParameterHint,
+            InlayKind::TypeHint => lsp_ext::InlayKind::TypeHint,
+            InlayKind::ChainingHint => lsp_ext::InlayKind::ChainingHint,
+        },
+    }
+}
+
+pub(crate) fn semantic_tokens(
+    text: &str,
+    line_index: &LineIndex,
+    highlights: Vec<HighlightedRange>,
+) -> lsp_types::SemanticTokens {
+    let mut builder = semantic_tokens::SemanticTokensBuilder::default();
+
+    for highlight_range in highlights {
+        let (type_, mods) = semantic_token_type_and_modifiers(highlight_range.highlight);
+        let token_index = semantic_tokens::type_index(type_);
+        let modifier_bitset = mods.0;
+
+        for mut text_range in line_index.lines(highlight_range.range) {
+            if text[text_range].ends_with('\n') {
+                text_range =
+                    TextRange::new(text_range.start(), text_range.end() - TextSize::of('\n'));
+            }
+            let range = range(&line_index, text_range);
+            builder.push(range, token_index, modifier_bitset);
+        }
+    }
+
+    builder.build()
+}
+
+fn semantic_token_type_and_modifiers(
+    highlight: Highlight,
+) -> (lsp_types::SemanticTokenType, semantic_tokens::ModifierSet) {
+    let mut mods = semantic_tokens::ModifierSet::default();
+    let type_ = match highlight.tag {
+        HighlightTag::Struct => lsp_types::SemanticTokenType::STRUCT,
+        HighlightTag::Enum => lsp_types::SemanticTokenType::ENUM,
+        HighlightTag::Union => semantic_tokens::UNION,
+        HighlightTag::TypeAlias => semantic_tokens::TYPE_ALIAS,
+        HighlightTag::Trait => lsp_types::SemanticTokenType::INTERFACE,
+        HighlightTag::BuiltinType => semantic_tokens::BUILTIN_TYPE,
+        HighlightTag::SelfType => lsp_types::SemanticTokenType::TYPE,
+        HighlightTag::Field => lsp_types::SemanticTokenType::MEMBER,
+        HighlightTag::Function => lsp_types::SemanticTokenType::FUNCTION,
+        HighlightTag::Module => lsp_types::SemanticTokenType::NAMESPACE,
+        HighlightTag::Constant => {
+            mods |= semantic_tokens::CONSTANT;
+            mods |= lsp_types::SemanticTokenModifier::STATIC;
+            lsp_types::SemanticTokenType::VARIABLE
+        }
+        HighlightTag::Static => {
+            mods |= lsp_types::SemanticTokenModifier::STATIC;
+            lsp_types::SemanticTokenType::VARIABLE
+        }
+        HighlightTag::EnumVariant => semantic_tokens::ENUM_MEMBER,
+        HighlightTag::Macro => lsp_types::SemanticTokenType::MACRO,
+        HighlightTag::Local => lsp_types::SemanticTokenType::VARIABLE,
+        HighlightTag::TypeParam => lsp_types::SemanticTokenType::TYPE_PARAMETER,
+        HighlightTag::Lifetime => semantic_tokens::LIFETIME,
+        HighlightTag::ByteLiteral | HighlightTag::NumericLiteral => {
+            lsp_types::SemanticTokenType::NUMBER
+        }
+        HighlightTag::CharLiteral | HighlightTag::StringLiteral => {
+            lsp_types::SemanticTokenType::STRING
+        }
+        HighlightTag::Comment => lsp_types::SemanticTokenType::COMMENT,
+        HighlightTag::Attribute => semantic_tokens::ATTRIBUTE,
+        HighlightTag::Keyword => lsp_types::SemanticTokenType::KEYWORD,
+        HighlightTag::UnresolvedReference => semantic_tokens::UNRESOLVED_REFERENCE,
+        HighlightTag::FormatSpecifier => semantic_tokens::FORMAT_SPECIFIER,
+    };
+
+    for modifier in highlight.modifiers.iter() {
+        let modifier = match modifier {
+            HighlightModifier::Definition => lsp_types::SemanticTokenModifier::DECLARATION,
+            HighlightModifier::ControlFlow => semantic_tokens::CONTROL_FLOW,
+            HighlightModifier::Mutable => semantic_tokens::MUTABLE,
+            HighlightModifier::Unsafe => semantic_tokens::UNSAFE,
+        };
+        mods |= modifier;
+    }
+
+    (type_, mods)
+}
+
+pub(crate) fn folding_range(
+    text: &str,
+    line_index: &LineIndex,
+    line_folding_only: bool,
+    fold: Fold,
+) -> lsp_types::FoldingRange {
+    let kind = match fold.kind {
+        FoldKind::Comment => Some(lsp_types::FoldingRangeKind::Comment),
+        FoldKind::Imports => Some(lsp_types::FoldingRangeKind::Imports),
+        FoldKind::Mods | FoldKind::Block => None,
+    };
+
+    let range = range(line_index, fold.range);
+
+    if line_folding_only {
+        // Clients with line_folding_only == true (such as VSCode) will fold the whole end line
+        // even if it contains text not in the folding range. To prevent that we exclude
+        // range.end.line from the folding region if there is more text after range.end
+        // on the same line.
+        let has_more_text_on_end_line = text[TextRange::new(fold.range.end(), TextSize::of(text))]
+            .chars()
+            .take_while(|it| *it != '\n')
+            .any(|it| !it.is_whitespace());
+
+        let end_line = if has_more_text_on_end_line {
+            range.end.line.saturating_sub(1)
+        } else {
+            range.end.line
+        };
+
+        lsp_types::FoldingRange {
+            start_line: range.start.line,
+            start_character: None,
+            end_line,
+            end_character: None,
+            kind,
+        }
+    } else {
+        lsp_types::FoldingRange {
+            start_line: range.start.line,
+            start_character: Some(range.start.character),
+            end_line: range.end.line,
+            end_character: Some(range.end.character),
+            kind,
+        }
+    }
+}
+
+pub(crate) fn url(world: &WorldSnapshot, file_id: FileId) -> Result<lsp_types::Url> {
+    world.file_id_to_uri(file_id)
+}
+
+pub(crate) fn text_document_identifier(
+    world: &WorldSnapshot,
+    file_id: FileId,
+) -> Result<lsp_types::TextDocumentIdentifier> {
+    let res = lsp_types::TextDocumentIdentifier { uri: url(world, file_id)? };
+    Ok(res)
+}
+
+pub(crate) fn versioned_text_document_identifier(
+    world: &WorldSnapshot,
+    file_id: FileId,
+    version: Option<i64>,
+) -> Result<lsp_types::VersionedTextDocumentIdentifier> {
+    let res = lsp_types::VersionedTextDocumentIdentifier { uri: url(world, file_id)?, version };
+    Ok(res)
+}
+
+pub(crate) fn location(world: &WorldSnapshot, frange: FileRange) -> Result<lsp_types::Location> {
+    let url = url(world, frange.file_id)?;
+    let line_index = world.analysis().file_line_index(frange.file_id)?;
+    let range = range(&line_index, frange.range);
+    let loc = lsp_types::Location::new(url, range);
+    Ok(loc)
+}
+
+pub(crate) fn location_link(
+    world: &WorldSnapshot,
+    src: FileRange,
+    target: NavigationTarget,
+) -> Result<lsp_types::LocationLink> {
+    let src_location = location(world, src)?;
+    let (target_uri, target_range, target_selection_range) = location_info(world, target)?;
+    let res = lsp_types::LocationLink {
+        origin_selection_range: Some(src_location.range),
+        target_uri,
+        target_range,
+        target_selection_range,
+    };
+    Ok(res)
+}
+
+fn location_info(
+    world: &WorldSnapshot,
+    target: NavigationTarget,
+) -> Result<(lsp_types::Url, lsp_types::Range, lsp_types::Range)> {
+    let line_index = world.analysis().file_line_index(target.file_id())?;
+
+    let target_uri = url(world, target.file_id())?;
+    let target_range = range(&line_index, target.full_range());
+    let target_selection_range =
+        target.focus_range().map(|it| range(&line_index, it)).unwrap_or(target_range);
+    Ok((target_uri, target_range, target_selection_range))
+}
+
+pub(crate) fn goto_definition_response(
+    world: &WorldSnapshot,
+    src: FileRange,
+    targets: Vec<NavigationTarget>,
+) -> Result<lsp_types::GotoDefinitionResponse> {
+    if world.config.client_caps.location_link {
+        let links = targets
+            .into_iter()
+            .map(|nav| location_link(world, src, nav))
+            .collect::<Result<Vec<_>>>()?;
+        Ok(links.into())
+    } else {
+        let locations = targets
+            .into_iter()
+            .map(|nav| {
+                location(
+                    world,
+                    FileRange {
+                        file_id: nav.file_id(),
+                        range: nav.focus_range().unwrap_or(nav.range()),
+                    },
+                )
+            })
+            .collect::<Result<Vec<_>>>()?;
+        Ok(locations.into())
+    }
+}
+
+pub(crate) fn text_document_edit(
+    world: &WorldSnapshot,
+    source_file_edit: SourceFileEdit,
+) -> Result<lsp_types::TextDocumentEdit> {
+    let text_document = versioned_text_document_identifier(world, source_file_edit.file_id, None)?;
+    let line_index = world.analysis().file_line_index(source_file_edit.file_id)?;
+    let line_endings = world.file_line_endings(source_file_edit.file_id);
+    let edits = source_file_edit
+        .edit
+        .as_indels()
+        .iter()
+        .map(|it| text_edit(&line_index, line_endings, it.clone()))
+        .collect();
+    Ok(lsp_types::TextDocumentEdit { text_document, edits })
+}
+
+pub(crate) fn resource_op(
+    world: &WorldSnapshot,
+    file_system_edit: FileSystemEdit,
+) -> Result<lsp_types::ResourceOp> {
+    let res = match file_system_edit {
+        FileSystemEdit::CreateFile { source_root, path } => {
+            let uri = world.path_to_uri(source_root, &path)?;
+            lsp_types::ResourceOp::Create(lsp_types::CreateFile { uri, options: None })
+        }
+        FileSystemEdit::MoveFile { src, dst_source_root, dst_path } => {
+            let old_uri = world.file_id_to_uri(src)?;
+            let new_uri = world.path_to_uri(dst_source_root, &dst_path)?;
+            lsp_types::ResourceOp::Rename(lsp_types::RenameFile { old_uri, new_uri, options: None })
+        }
+    };
+    Ok(res)
+}
+
+pub(crate) fn source_change(
+    world: &WorldSnapshot,
+    source_change: SourceChange,
+) -> Result<lsp_ext::SourceChange> {
+    let cursor_position = match source_change.cursor_position {
+        None => None,
+        Some(pos) => {
+            let line_index = world.analysis().file_line_index(pos.file_id)?;
+            let edit = source_change
+                .source_file_edits
+                .iter()
+                .find(|it| it.file_id == pos.file_id)
+                .map(|it| &it.edit);
+            let line_col = match edit {
+                Some(edit) => translate_offset_with_edit(&*line_index, pos.offset, edit),
+                None => line_index.line_col(pos.offset),
+            };
+            let position =
+                lsp_types::Position::new(u64::from(line_col.line), u64::from(line_col.col_utf16));
+            Some(lsp_types::TextDocumentPositionParams {
+                text_document: text_document_identifier(world, pos.file_id)?,
+                position,
+            })
+        }
+    };
+    let mut document_changes: Vec<lsp_types::DocumentChangeOperation> = Vec::new();
+    for op in source_change.file_system_edits {
+        let op = resource_op(&world, op)?;
+        document_changes.push(lsp_types::DocumentChangeOperation::Op(op));
+    }
+    for edit in source_change.source_file_edits {
+        let edit = text_document_edit(&world, edit)?;
+        document_changes.push(lsp_types::DocumentChangeOperation::Edit(edit));
+    }
+    let workspace_edit = lsp_types::WorkspaceEdit {
+        changes: None,
+        document_changes: Some(lsp_types::DocumentChanges::Operations(document_changes)),
+    };
+    Ok(lsp_ext::SourceChange { label: source_change.label, workspace_edit, cursor_position })
+}
+
+pub fn call_hierarchy_item(
+    world: &WorldSnapshot,
+    target: NavigationTarget,
+) -> Result<lsp_types::CallHierarchyItem> {
+    let name = target.name().to_string();
+    let detail = target.description().map(|it| it.to_string());
+    let kind = symbol_kind(target.kind());
+    let (uri, range, selection_range) = location_info(world, target)?;
+    Ok(lsp_types::CallHierarchyItem { name, kind, tags: None, detail, uri, range, selection_range })
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::extract_ranges;
+
+    use super::*;
+
+    #[test]
+    fn conv_fold_line_folding_only_fixup() {
+        let text = r#"<fold>mod a;
+mod b;
+mod c;</fold>
+
+fn main() <fold>{
+    if cond <fold>{
+        a::do_a();
+    }</fold> else <fold>{
+        b::do_b();
+    }</fold>
+}</fold>"#;
+
+        let (ranges, text) = extract_ranges(text, "fold");
+        assert_eq!(ranges.len(), 4);
+        let folds = vec![
+            Fold { range: ranges[0], kind: FoldKind::Mods },
+            Fold { range: ranges[1], kind: FoldKind::Block },
+            Fold { range: ranges[2], kind: FoldKind::Block },
+            Fold { range: ranges[3], kind: FoldKind::Block },
+        ];
+
+        let line_index = LineIndex::new(&text);
+        let converted: Vec<lsp_types::FoldingRange> =
+            folds.into_iter().map(|it| folding_range(&text, &line_index, true, it)).collect();
+
+        let expected_lines = [(0, 2), (4, 10), (5, 6), (7, 9)];
+        assert_eq!(converted.len(), expected_lines.len());
+        for (folding_range, (start_line, end_line)) in converted.iter().zip(expected_lines.iter()) {
+            assert_eq!(folding_range.start_line, *start_line);
+            assert_eq!(folding_range.start_character, None);
+            assert_eq!(folding_range.end_line, *end_line);
+            assert_eq!(folding_range.end_character, None);
+        }
+    }
+}
+
+pub(crate) fn code_action(world: &WorldSnapshot, assist: Assist) -> Result<lsp_types::CodeAction> {
+    let source_change = source_change(&world, assist.source_change)?;
+    let arg = serde_json::to_value(source_change)?;
+    let title = assist.label;
+    let command = lsp_types::Command {
+        title: title.clone(),
+        command: "rust-analyzer.applySourceChange".to_string(),
+        arguments: Some(vec![arg]),
+    };
+
+    Ok(lsp_types::CodeAction {
+        title,
+        kind: Some(String::new()),
+        diagnostics: None,
+        edit: None,
+        command: Some(command),
+        is_preferred: None,
+    })
+}