6 files changed, 116 insertions, 43 deletions

diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index d64f9a3f9..65ad573d8 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -1,8 +1,25 @@
 import * as lc from 'vscode-languageclient';
 import * as vscode from 'vscode';
+import * as ra from '../src/lsp_ext';
+import * as Is from 'vscode-languageclient/lib/utils/is';
 
 import { CallHierarchyFeature } from 'vscode-languageclient/lib/callHierarchy.proposed';
 import { SemanticTokensFeature, DocumentSemanticsTokensSignature } from 'vscode-languageclient/lib/semanticTokens.proposed';
+import { assert } from './util';
+
+function renderCommand(cmd: ra.CommandLink) {
+    return `[${cmd.title}](command:${cmd.command}?${encodeURIComponent(JSON.stringify(cmd.arguments))} '${cmd.tooltip!}')`;
+}
+
+function renderHoverActions(actions: ra.CommandLinkGroup[]): vscode.MarkdownString {
+    const text = actions.map(group =>
+        (group.title ? (group.title + " ") : "") + group.commands.map(renderCommand).join(' | ')
+    ).join('___');
+
+    const result = new vscode.MarkdownString(text);
+    result.isTrusted = true;
+    return result;
+}
 
 export function createClient(serverPath: string, cwd: string): lc.LanguageClient {
     // '.' Is the fallback if no folder is open
@@ -32,6 +49,25 @@ export function createClient(serverPath: string, cwd: string): lc.LanguageClient
                 if (res === undefined) throw new Error('busy');
                 return res;
             },
+            async provideHover(document: vscode.TextDocument, position: vscode.Position, token: vscode.CancellationToken, _next: lc.ProvideHoverSignature) {
+                return client.sendRequest(lc.HoverRequest.type, client.code2ProtocolConverter.asTextDocumentPositionParams(document, position), token).then(
+                    (result) => {
+                        const hover = client.protocol2CodeConverter.asHover(result);
+                        if (hover) {
+                            const actions = (<any>result).actions;
+                            if (actions) {
+                                hover.contents.push(renderHoverActions(actions));
+                            }
+                        }
+                        return hover;
+                    },
+                    (error) => {
+                        client.logFailedRequest(lc.HoverRequest.type, error);
+                        return Promise.resolve(null);
+                    });
+            },
+            // Using custom handling of CodeActions where each code action is resloved lazily
+            // That's why we are not waiting for any command or edits
             async provideCodeActions(document: vscode.TextDocument, range: vscode.Range, context: vscode.CodeActionContext, token: vscode.CancellationToken, _next: lc.ProvideCodeActionsSignature) {
                 const params: lc.CodeActionParams = {
                     textDocument: client.code2ProtocolConverter.asTextDocumentIdentifier(document),
@@ -43,32 +79,36 @@ export function createClient(serverPath: string, cwd: string): lc.LanguageClient
                     const result: (vscode.CodeAction | vscode.Command)[] = [];
                     const groups = new Map<string, { index: number; items: vscode.CodeAction[] }>();
                     for (const item of values) {
+                        // In our case we expect to get code edits only from diagnostics
                         if (lc.CodeAction.is(item)) {
+                            assert(!item.command, "We don't expect to receive commands in CodeActions");
                             const action = client.protocol2CodeConverter.asCodeAction(item);
-                            const group = actionGroup(item);
-                            if (isSnippetEdit(item) || group) {
-                                action.command = {
-                                    command: "rust-analyzer.applySnippetWorkspaceEdit",
-                                    title: "",
-                                    arguments: [action.edit],
-                                };
-                                action.edit = undefined;
-                            }
-
-                            if (group) {
-                                let entry = groups.get(group);
-                                if (!entry) {
-                                    entry = { index: result.length, items: [] };
-                                    groups.set(group, entry);
-                                    result.push(action);
-                                }
-                                entry.items.push(action);
-                            } else {
+                            result.push(action);
+                            continue;
+                        }
+                        assert(isCodeActionWithoutEditsAndCommands(item), "We don't expect edits or commands here");
+                        const action = new vscode.CodeAction(item.title);
+                        const group = (item as any).group;
+                        const id = (item as any).id;
+                        const resolveParams: ra.ResolveCodeActionParams = {
+                            id: id,
+                            codeActionParams: params
+                        };
+                        action.command = {
+                            command: "rust-analyzer.resolveCodeAction",
+                            title: item.title,
+                            arguments: [resolveParams],
+                        };
+                        if (group) {
+                            let entry = groups.get(group);
+                            if (!entry) {
+                                entry = { index: result.length, items: [] };
+                                groups.set(group, entry);
                                 result.push(action);
                             }
+                            entry.items.push(action);
                         } else {
-                            const command = client.protocol2CodeConverter.asCommand(item);
-                            result.push(command);
+                            result.push(action);
                         }
                     }
                     for (const [group, { index, items }] of groups) {
@@ -80,7 +120,7 @@ export function createClient(serverPath: string, cwd: string): lc.LanguageClient
                                 command: "rust-analyzer.applyActionGroup",
                                 title: "",
                                 arguments: [items.map((item) => {
-                                    return { label: item.title, edit: item.command!!.arguments!![0] };
+                                    return { label: item.title, arguments: item.command!!.arguments!![0] };
                                 })],
                             };
                             result[index] = action;
@@ -119,24 +159,18 @@ class ExperimentalFeatures implements lc.StaticFeature {
         const caps: any = capabilities.experimental ?? {};
         caps.snippetTextEdit = true;
         caps.codeActionGroup = true;
+        caps.resolveCodeAction = true;
+        caps.hoverActions = true;
         capabilities.experimental = caps;
     }
     initialize(_capabilities: lc.ServerCapabilities<any>, _documentSelector: lc.DocumentSelector | undefined): void {
     }
 }
 
-function isSnippetEdit(action: lc.CodeAction): boolean {
-    const documentChanges = action.edit?.documentChanges ?? [];
-    for (const edit of documentChanges) {
-        if (lc.TextDocumentEdit.is(edit)) {
-            if (edit.edits.some((indel) => (indel as any).insertTextFormat === lc.InsertTextFormat.Snippet)) {
-                return true;
-            }
-        }
-    }
-    return false;
-}
-
-function actionGroup(action: lc.CodeAction): string | undefined {
-    return (action as any).group;
+function isCodeActionWithoutEditsAndCommands(value: any): boolean {
+    const candidate: lc.CodeAction = value;
+    return candidate && Is.string(candidate.title) &&
+        (candidate.diagnostics === void 0 || Is.typedArray(candidate.diagnostics, lc.Diagnostic.is)) &&
+        (candidate.kind === void 0 || Is.string(candidate.kind)) &&
+        (candidate.edit === void 0 && candidate.command === void 0);
 }
diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index 534d2a984..3e9c3aa0e 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -343,10 +343,25 @@ export function showReferences(ctx: Ctx): Cmd {
 }
 
 export function applyActionGroup(_ctx: Ctx): Cmd {
-    return async (actions: { label: string; edit: vscode.WorkspaceEdit }[]) => {
+    return async (actions: { label: string; arguments: ra.ResolveCodeActionParams }[]) => {
         const selectedAction = await vscode.window.showQuickPick(actions);
         if (!selectedAction) return;
-        await applySnippetWorkspaceEdit(selectedAction.edit);
+        vscode.commands.executeCommand(
+            'rust-analyzer.resolveCodeAction',
+            selectedAction.arguments,
+        );
+    };
+}
+
+export function resolveCodeAction(ctx: Ctx): Cmd {
+    const client = ctx.client;
+    return async (params: ra.ResolveCodeActionParams) => {
+        const item: lc.WorkspaceEdit = await client.sendRequest(ra.resolveCodeAction, params);
+        if (!item) {
+            return;
+        }
+        const edit = client.protocol2CodeConverter.asWorkspaceEdit(item);
+        await applySnippetWorkspaceEdit(edit);
     };
 }
 
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index e8abf8284..d8f0037d4 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -16,10 +16,8 @@ export class Config {
         "files",
         "highlighting",
         "updates.channel",
-        "lens.enable",
-        "lens.run",
-        "lens.debug",
-        "lens.implementations",
+        "lens", // works as lens.*
+        "hoverActions", // works as hoverActions.*
     ]
         .map(opt => `${this.rootSection}.${opt}`);
 
@@ -132,4 +130,11 @@ export class Config {
             implementations: this.get<boolean>("lens.implementations"),
         };
     }
+
+    get hoverActions() {
+        return {
+            enable: this.get<boolean>("hoverActions.enable"),
+            implementations: this.get<boolean>("hoverActions.implementations"),
+        };
+    }
 }
diff --git a/editors/code/src/lsp_ext.ts b/editors/code/src/lsp_ext.ts
index c51acfccb..e16ea799c 100644
--- a/editors/code/src/lsp_ext.ts
+++ b/editors/code/src/lsp_ext.ts
@@ -33,6 +33,12 @@ export const matchingBrace = new lc.RequestType<MatchingBraceParams, lc.Position
 
 export const parentModule = new lc.RequestType<lc.TextDocumentPositionParams, lc.LocationLink[], void>("experimental/parentModule");
 
+export interface ResolveCodeActionParams {
+    id: string;
+    codeActionParams: lc.CodeActionParams;
+}
+export const resolveCodeAction = new lc.RequestType<ResolveCodeActionParams, lc.WorkspaceEdit, unknown>('experimental/resolveCodeAction');
+
 export interface JoinLinesParams {
     textDocument: lc.TextDocumentIdentifier;
     ranges: lc.Range[];
@@ -84,3 +90,15 @@ export interface SsrParams {
     parseOnly: boolean;
 }
 export const ssr = new lc.RequestType<SsrParams, lc.WorkspaceEdit, void>('experimental/ssr');
+
+export interface CommandLink extends lc.Command {
+    /**
+     * A tooltip for the command, when represented in the UI.
+     */
+    tooltip?: string;
+}
+
+export interface CommandLinkGroup {
+    title?: string;
+    commands: CommandLink[];
+}
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index b7337621c..a92c676fa 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -98,6 +98,7 @@ export async function activate(context: vscode.ExtensionContext) {
     ctx.registerCommand('debugSingle', commands.debugSingle);
     ctx.registerCommand('showReferences', commands.showReferences);
     ctx.registerCommand('applySnippetWorkspaceEdit', commands.applySnippetWorkspaceEditCommand);
+    ctx.registerCommand('resolveCodeAction', commands.resolveCodeAction);
     ctx.registerCommand('applyActionGroup', commands.applyActionGroup);
 
     ctx.pushCleanup(activateTaskProvider(workspaceFolder));
diff --git a/editors/code/src/run.ts b/editors/code/src/run.ts
index 5c790741f..bb060cfe1 100644
--- a/editors/code/src/run.ts
+++ b/editors/code/src/run.ts
@@ -110,7 +110,7 @@ export function createTask(runnable: ra.Runnable): vscode.Task {
     switch (runnable.kind) {
         case "cargo": command = toolchain.getPathForExecutable("cargo");
     }
-    const args = runnable.args.cargoArgs;
+    const args = [...runnable.args.cargoArgs]; // should be a copy!
     if (runnable.args.executableArgs.length > 0) {
         args.push('--', ...runnable.args.executableArgs);
     }