feat(tolk/completion): add completion option for field with Cell<Foo> type, to create Foo {}.toCell() expression

server/src/e2e/tolk/testcases/completion/struct-instance.test

@@ -160,3 +160,30 @@ fun main(foo: Foo = {<caret>}) {}
 ------------------------------------------------------------------------
 9  first : int    of Foo
 9  second : slice    of Foo
+
+========================================================================
+Fields completion with Cell<T> type
+========================================================================
+struct Cell<T> {
+    tvmCell: cell
+}
+
+struct Inner {
+    bar: int
+}
+
+struct Data {
+    foo: Cell<Inner>
+}
+
+fun test() {
+    Data {
+        foo: In<caret>,
+    }
+}
+------------------------------------------------------------------------
+21 InMessage {}
+21 InMessageBounced {}
+21 Inner {}
+21 StateInit {}
+14 Inner {}.toCell()

server/src/e2e/tolk/testcases/intentions/FillFieldsStructInit.test

@@ -432,3 +432,33 @@ fun foo() {
         body: null,
     });
 }
+
+========================================================================
+@intention Fill all fields...
+Struct with Cell<Foo> field
+========================================================================
+struct Inner {
+    bar: int
+}
+
+struct Data {
+    foo: Cell<Inner>
+}
+
+fun test() {
+    Data {<caret>}
+}
+------------------------------------------------------------------------
+struct Inner {
+    bar: int
+}
+
+struct Data {
+    foo: Cell<Inner>
+}
+
+fun test() {
+    Data {
+        foo: Inner {}.toCell(),
+    }
+}

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

@@ -21,6 +21,7 @@ export class CompletionContext {
     public isAnnotationName: boolean = false
     public expectMatchArm: boolean = false
     public catchVariable: boolean = false
+    public fieldInit: boolean = false
 
     // struct fields
     public inNameOfFieldInit: boolean = false
@@ -59,6 +60,13 @@ export class CompletionContext {
             this.catchVariable = true
         }
 
+        if (parent.type === "instance_argument") {
+            const value = parent.childForFieldName("value")
+            if (value?.equals(element.node)) {
+                this.fieldInit = true
+            }
+        }
+
         if (parent.type === "binary_operator" && parent.parent?.type === "match_arm") {
             // match (a) {
             //     <caret>

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

@@ -32,6 +32,7 @@ import {ExpressionSnippetsCompletionProvider} from "@server/languages/tolk/compl
 import {MatchArmsCompletionProvider} from "@server/languages/tolk/completion/providers/MatchArmsCompletionProvider"
 import {CompletionItemAdditionalInformation} from "@server/completion/CompletionItemAdditionalInformation"
 import {StorageCompletionProvider} from "@server/languages/tolk/completion/providers/StorageCompletionProvider"
+import {FieldInitCompletionProvider} from "@server/languages/tolk/completion/providers/FieldInitCompletionProvider"
 
 export async function provideTolkCompletion(
     file: TolkFile,
@@ -112,6 +113,7 @@ export async function provideTolkCompletion(
         new VariableSizeTypeCompletionProvider(),
         new MatchArmsCompletionProvider(ref),
         new StorageCompletionProvider(),
+        new FieldInitCompletionProvider(),
     ]
 
     for (const provider of providers) {

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

@@ -0,0 +1,48 @@
+//  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"
+import {Reference} from "@server/languages/tolk/psi/Reference"
+import {NamedNode} from "@server/languages/tolk/psi/TolkNode"
+import {typeOf} from "@server/languages/tolk/type-inference"
+import {InstantiationTy, StructTy} from "@server/languages/tolk/types/ty"
+
+export class FieldInitCompletionProvider implements CompletionProvider<CompletionContext> {
+    public isAvailable(ctx: CompletionContext): boolean {
+        return ctx.fieldInit
+    }
+
+    public addCompletion(ctx: CompletionContext, result: CompletionResult): void {
+        const instanceArgument = ctx.element.parentOfType("instance_argument")
+        if (!instanceArgument) return
+
+        const fieldName = instanceArgument.childForFieldName("name")
+        if (!fieldName) return
+
+        const field = Reference.resolve(new NamedNode(fieldName, ctx.element.file))
+        if (!field) return
+
+        const fieldType = typeOf(field.node, field.file)
+        if (!fieldType) return
+
+        if (
+            fieldType instanceof InstantiationTy &&
+            fieldType.types.length > 0 &&
+            fieldType.innerTy.name() === "Cell" &&
+            fieldType.types[0] instanceof StructTy
+        ) {
+            // Cell<Foo> => Foo{}.toCell()
+            const argTy = fieldType.types[0]
+
+            result.add({
+                label: argTy.name() + " {}.toCell()",
+                kind: CompletionItemKind.Snippet,
+                insertTextFormat: InsertTextFormat.Snippet,
+                insertText: argTy.name() + " {$0}.toCell()",
+                weight: CompletionWeight.CONTEXT_ELEMENT,
+            })
+        }
+    }
+}

server/src/languages/tolk/intentions/FillFieldsStructInit.ts

@@ -15,6 +15,7 @@ import {
     BytesNTy,
     CoinsTy,
     FieldsOwnerTy,
+    InstantiationTy,
     IntTy,
     NullTy,
     StructTy,
@@ -231,6 +232,17 @@ export class FillStructInitBase implements Intention {
             return this.typeDefaultValue(type.innerTy)
         }
 
+        if (type instanceof InstantiationTy) {
+            if (
+                type.innerTy instanceof StructTy &&
+                type.innerTy.name() === "Cell" &&
+                type.types.length > 0
+            ) {
+                return this.typeDefaultValue(type.types[0]) + ".toCell()"
+            }
+            return this.typeDefaultValue(type.innerTy)
+        }
+
         return "null"
     }
 }