feat(tolk/inspections): warn about unused packToBuilder and unpackFromSlice methods for non-alias types and with wrong signature

server/src/e2e/tolk/testcases/inspections/UnusedTopLevelDeclarationInspectionUnpackPackMethods.test

@@ -0,0 +1,102 @@
+========================================================================
+unpackFromSlice correct signature for type alias
+========================================================================
+type SnakeString = slice
+
+fun SnakeString.unpackFromSlice(mutate s: slice) {
+}
+------------------------------------------------------------------------
+no issues
+
+========================================================================
+packToBuilder correct signature for type alias
+========================================================================
+type SnakeString = slice
+
+fun SnakeString.packToBuilder(self, mutate b: builder) {
+}
+------------------------------------------------------------------------
+no issues
+
+========================================================================
+unpackFromSlice for regular struct, should warn
+========================================================================
+struct RegularStruct {
+    value: int
+}
+
+fun RegularStruct.unpackFromSlice(mutate s: slice) {
+}
+------------------------------------------------------------------------
+3 1:4 to 1:14 Field 'value' is never used (tolk)
+3 4:18 to 4:33 Method 'unpackFromSlice' is never used, note, special `unpackFromSlice` method can be used only for type aliases to change serialization/deserialization logic (tolk)
+
+========================================================================
+packToBuilder for regular struct, should warn
+========================================================================
+struct RegularStruct {
+    value: int
+}
+
+fun RegularStruct.packToBuilder(self, mutate b: builder) {
+}
+------------------------------------------------------------------------
+3 1:4 to 1:14 Field 'value' is never used (tolk)
+3 4:18 to 4:31 Method 'packToBuilder' is never used, note, special `packToBuilder` method can be used only for type aliases to change serialization/deserialization logic (tolk)
+
+========================================================================
+static packToBuilder, should warn
+========================================================================
+type SnakeString = slice
+
+fun SnakeString.packToBuilder(mutate b: builder) {
+}
+------------------------------------------------------------------------
+3 2:16 to 2:29 Method 'packToBuilder' is never used, if you want custom serialization/deserialization logic, check signature of `packToBuilder` method, it should be like: `fun Type.packToBuilder(self, mutate b: builder)` (tolk)
+
+========================================================================
+unpackFromSlice with extra parameters, should warn
+========================================================================
+type SnakeString = slice
+
+fun SnakeString.unpackFromSlice(mutate s: slice, extra: int) {
+}
+------------------------------------------------------------------------
+3 2:16 to 2:31 Method 'unpackFromSlice' is never used, if you want custom serialization/deserialization logic, check signature of `unpackFromSlice` method, it should be like: `fun Type.unpackFromSlice(mutate s: slice)` (tolk)
+
+========================================================================
+packToBuilder with extra parameters, should warn
+========================================================================
+type SnakeString = slice
+
+fun SnakeString.packToBuilder(self, mutate b: builder, extra: int) {
+}
+------------------------------------------------------------------------
+3 2:16 to 2:29 Method 'packToBuilder' is never used, if you want custom serialization/deserialization logic, check signature of `packToBuilder` method, it should be like: `fun Type.packToBuilder(self, mutate b: builder)` (tolk)
+
+========================================================================
+Multiple type aliases with correct special methods
+========================================================================
+type String1 = slice
+type String2 = slice
+
+fun String1.unpackFromSlice(mutate s: slice) {}
+fun String1.packToBuilder(self, mutate b: builder) {}
+fun String2.unpackFromSlice(mutate s: slice) {}
+fun String2.packToBuilder(self, mutate b: builder) {}
+------------------------------------------------------------------------
+no issues
+
+========================================================================
+Mixed correct and incorrect special methods
+========================================================================
+type String1 = slice
+type String2 = slice
+
+fun String1.unpackFromSlice(mutate s: slice) {} // correct
+fun String1.packToBuilder(mutate b: builder) {} // wrong: missing self
+fun String2.unpackFromSlice(s: slice, o: int) {} // wrong: extra argument
+fun String2.packToBuilder(self, mutate b: builder) {} // correct
+------------------------------------------------------------------------
+3 4:12 to 4:25 Method 'packToBuilder' is never used, if you want custom serialization/deserialization logic, check signature of `packToBuilder` method, it should be like: `fun Type.packToBuilder(self, mutate b: builder)` (tolk)
+3 5:12 to 5:27 Method 'unpackFromSlice' is never used, if you want custom serialization/deserialization logic, check signature of `unpackFromSlice` method, it should be like: `fun Type.unpackFromSlice(mutate s: slice)` (tolk)

server/src/languages/tolk/inspections/UnusedInspection.ts

@@ -25,6 +25,7 @@ export abstract class UnusedInspection {
             severity?: lsp.DiagnosticSeverity
             code?: string
             rangeNode?: SyntaxNode | null
+            additionalText?: string | null
             skipIf?: () => boolean
         },
     ): void {
@@ -41,7 +42,8 @@ export abstract class UnusedInspection {
             diagnostics.push({
                 severity: options.severity ?? lsp.DiagnosticSeverity.Hint,
                 range,
-                message: `${options.kind} '${node.text}' is never used`,
+                message:
+                    `${options.kind} '${node.text}' is never used` + (options.additionalText ?? ""),
                 source: "tolk",
                 code: options.code ?? "unused",
                 tags: [lsp.DiagnosticTag.Unnecessary],

server/src/languages/tolk/inspections/UnusedTopLevelDeclarationInspection.ts

@@ -9,9 +9,14 @@ import {
     Enum,
     Func,
     GlobalVariable,
+    InstanceMethod,
+    MethodBase,
+    StaticMethod,
     Struct,
     TypeAlias,
 } from "@server/languages/tolk/psi/Decls"
+import {inferenceOf} from "@server/languages/tolk/type-inference"
+import {FuncTy, TypeAliasTy} from "@server/languages/tolk/types/ty"
 
 const IMPLICITLY_USED_FUNCTIONS: Set<string> = new Set([
     "onInternalMessage",
@@ -23,8 +28,6 @@ const IMPLICITLY_USED_FUNCTIONS: Set<string> = new Set([
     "main",
 ])
 
-const IMPLICITLY_USED_METHODS: Set<string> = new Set(["unpackFromSlice", "packToBuilder"])
-
 export class UnusedTopLevelDeclarationInspection extends UnusedInspection implements Inspection {
     public readonly id: "unused-top-level-declaration" = InspectionIds.UNUSED_TOP_LEVEL_DECLARATION
 
@@ -74,7 +77,30 @@ export class UnusedTopLevelDeclarationInspection extends UnusedInspection implem
 
     private inspectMethod(fun: Func, diagnostics: lsp.Diagnostic[]): void {
         const name = fun.name()
-        if (IMPLICITLY_USED_METHODS.has(name)) {
+        if (this.isUnpackFromSlice(fun) || this.isPackToBuilder(fun)) {
+            return
+        }
+
+        const isSpecialMethod = name === "packToBuilder" || name === "unpackFromSlice"
+        if (isSpecialMethod) {
+            if (this.isMethodOfAlias(fun)) {
+                const expectedSignature =
+                    name === "packToBuilder" ? "self, mutate b: builder" : "mutate s: slice"
+
+                this.checkUnused(fun.nameIdentifier(), fun.file, diagnostics, {
+                    kind: "Method",
+                    code: "unused-method",
+                    additionalText: `, if you want custom serialization/deserialization logic, check signature of \`${name}\` method, it should be like: \`fun Type.${name}(${expectedSignature})\``,
+                    rangeNode: fun.nameIdentifier(),
+                })
+            } else {
+                this.checkUnused(fun.nameIdentifier(), fun.file, diagnostics, {
+                    kind: "Method",
+                    code: "unused-method",
+                    additionalText: `, note, special \`${name}\` method can be used only for type aliases to change serialization/deserialization logic`,
+                    rangeNode: fun.nameIdentifier(),
+                })
+            }
             return
         }
 
@@ -140,4 +166,50 @@ export class UnusedTopLevelDeclarationInspection extends UnusedInspection implem
             })
         }
     }
+
+    private isMethodOfAlias(fun: Func): boolean {
+        if (!(fun instanceof MethodBase)) return false
+
+        const inference = inferenceOf(fun.node, fun.file)
+        if (!inference) return false
+
+        const receiverTy = inference.typeOf(fun.receiverTypeNode())
+        if (!receiverTy) return false
+
+        return receiverTy instanceof TypeAliasTy
+    }
+
+    private isUnpackFromSlice(fun: Func): boolean {
+        return this.isMethod(fun, "unpackFromSlice", true, "slice")
+    }
+
+    private isPackToBuilder(fun: Func): boolean {
+        return this.isMethod(fun, "packToBuilder", false, "builder")
+    }
+
+    private isMethod(fun: Func, name: string, isStatic: boolean, expectedParams: string): boolean {
+        const hasName = fun.name() === name
+        if (!hasName) return false
+
+        if (!(fun instanceof MethodBase)) return false
+        if (isStatic && fun instanceof InstanceMethod) return false
+        if (!isStatic && fun instanceof StaticMethod) return false
+
+        const inference = inferenceOf(fun.node, fun.file)
+        if (!inference) return hasName
+
+        const actualFuncTy = inference.typeOf(fun.node)
+        if (!actualFuncTy || !(actualFuncTy instanceof FuncTy)) return hasName
+
+        const receiverTy = inference.typeOf(fun.receiverTypeNode())
+        if (!receiverTy) return false
+
+        const params =
+            fun instanceof InstanceMethod ? actualFuncTy.params.slice(1) : actualFuncTy.params
+
+        return (
+            receiverTy instanceof TypeAliasTy &&
+            params.map(it => it.name()).join(", ") === expectedParams
+        )
+    }
 }

server/src/languages/tolk/type-inference.ts

@@ -2586,7 +2586,8 @@ export class SinkExpression {
 export class InferenceResult {
     public constructor(public ctx: InferenceContext) {}
 
-    public typeOf(node: SyntaxNode): Ty | null {
+    public typeOf(node: SyntaxNode | null): Ty | null {
+        if (!node) return null
         return this.ctx.getType(node)
     }