feat(tolk/completion): add storage snippet

server/src/e2e/tolk/testcases/completion/top-level.test

@@ -19,6 +19,7 @@ Top level completion
 14 onExternalMessage
 14 onInternalMessage
 14 onTickTock
+14 storage
 
 ========================================================================
 Top level completion after declaration
@@ -43,6 +44,7 @@ fun foo() {}
 14 onExternalMessage
 14 onInternalMessage
 14 onTickTock
+14 storage
 
 ========================================================================
 Top level completion before declaration and after import
@@ -69,6 +71,7 @@ fun foo() {}
 14 onExternalMessage
 14 onInternalMessage
 14 onTickTock
+14 storage
 
 ========================================================================
 No top level completion inside function

server/src/languages/tolk/completion/index.ts

@@ -31,6 +31,7 @@ import {VariableSizeTypeCompletionProvider} from "@server/languages/tolk/complet
 import {ExpressionSnippetsCompletionProvider} from "@server/languages/tolk/completion/providers/ExpressionSnippetsCompletionProvider"
 import {MatchArmsCompletionProvider} from "@server/languages/tolk/completion/providers/MatchArmsCompletionProvider"
 import {CompletionItemAdditionalInformation} from "@server/completion/CompletionItemAdditionalInformation"
+import {StorageCompletionProvider} from "@server/languages/tolk/completion/providers/StorageCompletionProvider"
 
 export async function provideTolkCompletion(
     file: TolkFile,
@@ -110,6 +111,7 @@ export async function provideTolkCompletion(
         new IndexAccessCompletionProvider(),
         new VariableSizeTypeCompletionProvider(),
         new MatchArmsCompletionProvider(ref),
+        new StorageCompletionProvider(),
     ]
 
     for (const provider of providers) {

server/src/languages/tolk/completion/providers/StorageCompletionProvider.ts

@@ -0,0 +1,32 @@
+//  SPDX-License-Identifier: MIT
+//  Copyright © 2025 TON Core
+import type {CompletionProvider} from "@server/completion/CompletionProvider"
+import {CompletionItemKind, InsertTextFormat} from "vscode-languageserver-types"
+import type {CompletionContext} from "@server/languages/tolk/completion/CompletionContext"
+import {CompletionResult, CompletionWeight} from "@server/completion/WeightedCompletionItem"
+
+export class StorageCompletionProvider implements CompletionProvider<CompletionContext> {
+    public isAvailable(ctx: CompletionContext): boolean {
+        return ctx.topLevel
+    }
+
+    public addCompletion(_ctx: CompletionContext, result: CompletionResult): void {
+        result.add({
+            label: "storage",
+            kind: CompletionItemKind.Snippet,
+            insertTextFormat: InsertTextFormat.Snippet,
+            insertText: `struct \${1:Storage} {
+    $0
+}
+
+fun \${1:Storage}.load() {
+    return \${1:Storage}.fromCell(contract.getData());
+}
+
+fun \${1:Storage}.save(self) {
+    contract.setData(self.toCell());
+}`,
+            weight: CompletionWeight.SNIPPET,
+        })
+    }
+}