3 files changed, 107 insertions, 77 deletions

diff --git a/editors/code/src/commands/index.ts b/editors/code/src/commands/index.ts
index a7f3bc4c1..8f91b3b7d 100644
--- a/editors/code/src/commands/index.ts
+++ b/editors/code/src/commands/index.ts
@@ -5,10 +5,10 @@ import { matchingBrace } from './matching_brace';
 import { joinLines } from './join_lines';
 import { onEnter } from './on_enter';
 import { parentModule } from './parent_module';
+import { syntaxTree } from './syntax_tree';
 import * as expandMacro from './expand_macro';
 import * as inlayHints from './inlay_hints';
 import * as runnables from './runnables';
-import * as syntaxTree from './syntaxTree';
 
 function collectGarbage(ctx: Ctx): Cmd {
     return async () => {
diff --git a/editors/code/src/commands/syntaxTree.ts b/editors/code/src/commands/syntaxTree.ts
deleted file mode 100644
index 89a80550c..000000000
--- a/editors/code/src/commands/syntaxTree.ts
+++ /dev/null
@@ -1,76 +0,0 @@
-import * as vscode from 'vscode';
-import { Range, TextDocumentIdentifier } from 'vscode-languageclient';
-
-import { Server } from '../server';
-
-export const syntaxTreeUri = vscode.Uri.parse('rust-analyzer://syntaxtree');
-
-export class SyntaxTreeContentProvider
-    implements vscode.TextDocumentContentProvider {
-    public eventEmitter = new vscode.EventEmitter<vscode.Uri>();
-    public syntaxTree: string = 'Not available';
-
-    public provideTextDocumentContent(
-        uri: vscode.Uri,
-    ): vscode.ProviderResult<string> {
-        const editor = vscode.window.activeTextEditor;
-        if (editor == null) {
-            return '';
-        }
-
-        let range: Range | undefined;
-
-        // When the range based query is enabled we take the range of the selection
-        if (uri.query === 'range=true') {
-            range = editor.selection.isEmpty
-                ? undefined
-                : Server.client.code2ProtocolConverter.asRange(
-                      editor.selection,
-                  );
-        }
-
-        const request: SyntaxTreeParams = {
-            textDocument: { uri: editor.document.uri.toString() },
-            range,
-        };
-        return Server.client.sendRequest<SyntaxTreeResult>(
-            'rust-analyzer/syntaxTree',
-            request,
-        );
-    }
-
-    get onDidChange(): vscode.Event<vscode.Uri> {
-        return this.eventEmitter.event;
-    }
-}
-
-interface SyntaxTreeParams {
-    textDocument: TextDocumentIdentifier;
-    range?: Range;
-}
-
-type SyntaxTreeResult = string;
-
-// Opens the virtual file that will show the syntax tree
-//
-// The contents of the file come from the `TextDocumentContentProvider`
-export function createHandle(provider: SyntaxTreeContentProvider) {
-    return async () => {
-        const editor = vscode.window.activeTextEditor;
-        const rangeEnabled = !!(editor && !editor.selection.isEmpty);
-
-        const uri = rangeEnabled
-            ? vscode.Uri.parse(`${syntaxTreeUri.toString()}?range=true`)
-            : syntaxTreeUri;
-
-        const document = await vscode.workspace.openTextDocument(uri);
-
-        provider.eventEmitter.fire(uri);
-
-        return vscode.window.showTextDocument(
-            document,
-            vscode.ViewColumn.Two,
-            true,
-        );
-    };
-}
diff --git a/editors/code/src/commands/syntax_tree.ts b/editors/code/src/commands/syntax_tree.ts
new file mode 100644
index 000000000..e61fb36df
--- /dev/null
+++ b/editors/code/src/commands/syntax_tree.ts
@@ -0,0 +1,106 @@
+import * as vscode from 'vscode';
+import * as lc from 'vscode-languageclient';
+
+import { Ctx, Cmd } from '../ctx';
+
+// Opens the virtual file that will show the syntax tree
+//
+// The contents of the file come from the `TextDocumentContentProvider`
+export function syntaxTree(ctx: Ctx): Cmd {
+    const stcp = new SyntaxTreeContentProvider(ctx);
+
+    ctx.pushCleanup(
+        vscode.workspace.registerTextDocumentContentProvider(
+            'rust-analyzer',
+            stcp,
+        ),
+    );
+
+    vscode.workspace.onDidChangeTextDocument(
+        (event: vscode.TextDocumentChangeEvent) => {
+            const doc = event.document;
+            if (doc.languageId !== 'rust') return;
+            afterLs(() => stcp.eventEmitter.fire(stcp.uri));
+        },
+        ctx.subscriptions,
+    );
+
+    vscode.window.onDidChangeActiveTextEditor(
+        (editor: vscode.TextEditor | undefined) => {
+            if (!editor || editor.document.languageId !== 'rust') return;
+            stcp.eventEmitter.fire(stcp.uri);
+        },
+        ctx.subscriptions,
+    );
+
+    return async () => {
+        const editor = vscode.window.activeTextEditor;
+        const rangeEnabled = !!(editor && !editor.selection.isEmpty);
+
+        const uri = rangeEnabled
+            ? vscode.Uri.parse(`${stcp.uri.toString()}?range=true`)
+            : stcp.uri;
+
+        const document = await vscode.workspace.openTextDocument(uri);
+
+        stcp.eventEmitter.fire(uri);
+
+        return vscode.window.showTextDocument(
+            document,
+            vscode.ViewColumn.Two,
+            true,
+        );
+    };
+}
+
+// We need to order this after LS updates, but there's no API for that.
+// Hence, good old setTimeout.
+function afterLs(f: () => any) {
+    setTimeout(f, 10);
+}
+
+interface SyntaxTreeParams {
+    textDocument: lc.TextDocumentIdentifier;
+    range?: lc.Range;
+}
+
+export class SyntaxTreeContentProvider
+    implements vscode.TextDocumentContentProvider {
+    ctx: Ctx;
+    uri = vscode.Uri.parse('rust-analyzer://syntaxtree');
+    eventEmitter = new vscode.EventEmitter<vscode.Uri>();
+    syntaxTree: string = 'Not available';
+
+    constructor(ctx: Ctx) {
+        this.ctx = ctx;
+    }
+
+    provideTextDocumentContent(uri: vscode.Uri): vscode.ProviderResult<string> {
+        const editor = vscode.window.activeTextEditor;
+        if (editor == null) return '';
+
+        let range: lc.Range | undefined;
+
+        // When the range based query is enabled we take the range of the selection
+        if (uri.query === 'range=true') {
+            range = editor.selection.isEmpty
+                ? undefined
+                : this.ctx.client.code2ProtocolConverter.asRange(
+                      editor.selection,
+                  );
+        }
+
+        const request: SyntaxTreeParams = {
+            textDocument: { uri: editor.document.uri.toString() },
+            range,
+        };
+        return this.ctx.client.sendRequest<string>(
+            'rust-analyzer/syntaxTree',
+            request,
+        );
+    }
+
+    get onDidChange(): vscode.Event<vscode.Uri> {
+        return this.eventEmitter.event;
+    }
+}