Enforce that 'fulfillingAdditionalTypes' parameter is of a valid type

Sources/SafeDICore/Extensions/AttributeListSyntaxExtensions.swift

@@ -22,7 +22,7 @@ import SwiftSyntax
 
 extension AttributeListSyntax {
 
-    var instantiableMacro: AttributeSyntax? {
+    public var instantiableMacro: AttributeSyntax? {
         guard let attribute = first(where: { element in
             switch element {
             case let .attribute(attribute):

Sources/SafeDICore/Extensions/AttributeSyntaxExtensions.swift

@@ -0,0 +1,37 @@
+// Distributed under the MIT License
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+import SwiftSyntax
+
+extension AttributeSyntax {
+
+    public var fulfillingAdditionalTypes: ExprSyntax? {
+        guard
+            let arguments,
+            let labeledExpressionList = LabeledExprListSyntax(arguments),
+            let firstLabeledExpression = labeledExpressionList.first,
+            firstLabeledExpression.label?.text == "fulfillingAdditionalTypes"
+        else {
+            return nil
+        }
+
+        return firstLabeledExpression.expression
+    }
+}

Sources/SafeDICore/Visitors/InstantiableVisitor.swift

@@ -180,13 +180,11 @@ public final class InstantiableVisitor: SyntaxVisitor {
 
     private func processAttributes(_ attributes: AttributeListSyntax, on node: some ConcreteDeclSyntaxProtocol) {
         guard let macro = attributes.instantiableMacro else {
-            assertionFailure("Constructing macro not found despite processing top-level declaration")
+            assertionFailure("Instantiable macro not found despite processing top-level declaration")
             return
         }
         guard 
-            let fulfillingAdditionalTypesArgument = macro.arguments,
-            let fulfillingAdditionalTypesExpressionList = LabeledExprListSyntax(fulfillingAdditionalTypesArgument),
-            let fulfillingAdditionalTypesExpression = fulfillingAdditionalTypesExpressionList.first?.expression,
+            let fulfillingAdditionalTypesExpression = macro.fulfillingAdditionalTypes,
             let fulfillingAdditionalTypesArray = ArrayExprSyntax(fulfillingAdditionalTypesExpression)
         else {
             // Nothing to do here.

Sources/SafeDIMacros/Macros/InstantiableMacro.swift

@@ -39,6 +39,12 @@ public struct InstantiableMacro: MemberMacro {
             throw InstantiableError.decoratingIncompatibleType
         }
 
+        if let fulfillingAdditionalTypesArgument = concreteDeclaration.attributes.instantiableMacro?.fulfillingAdditionalTypes {
+            if ArrayExprSyntax(fulfillingAdditionalTypesArgument) == nil {
+                throw InstantiableError.fulfillingAdditionalTypesArgumentInvalid
+            }
+        }
+
         let visitor = InstantiableVisitor()
         visitor.walk(concreteDeclaration)
         for diagnostic in visitor.diagnostics {
@@ -83,13 +89,16 @@ public struct InstantiableMacro: MemberMacro {
     private enum InstantiableError: Error, CustomStringConvertible {
         case decoratingIncompatibleType
         case tooManyForwardedProperties
+        case fulfillingAdditionalTypesArgumentInvalid
 
         var description: String {
             switch self {
             case .decoratingIncompatibleType:
                 "@\(InstantiableVisitor.macroName) must decorate a class, struct, or actor"
             case .tooManyForwardedProperties:
                 "An @\(InstantiableVisitor.macroName) type must have at most one @\(Dependency.Source.forwarded.rawValue) property"
+            case .fulfillingAdditionalTypesArgumentInvalid:
+                "The argument `fulfillingAdditionalTypes` must be an inlined array"
             }
         }
     }

Tests/SafeDIMacrosTests/InstantiableMacroTests.swift

@@ -78,6 +78,40 @@ final class InstantiableMacroTests: XCTestCase {
         }
     }
 
+    func test_throwsErrorWhenFulfillingAdditionalTypesIsAPropertyReference() {
+        assertMacro {
+            """
+            let fulfillingAdditionalTypes: [Any.Type] = [AnyObject.self]
+            @Instantiable(fulfillingAdditionalTypes: fulfillingAdditionalTypes)
+            public final class ExampleService {}
+            """
+        } diagnostics: {
+            """
+            let fulfillingAdditionalTypes: [Any.Type] = [AnyObject.self]
+            @Instantiable(fulfillingAdditionalTypes: fulfillingAdditionalTypes)
+            ┬──────────────────────────────────────────────────────────────────
+            ╰─ 🛑 The argument `fulfillingAdditionalTypes` must be an inlined array
+            public final class ExampleService {}
+            """
+        }
+    }
+
+    func test_throwsErrorWhenFulfillingAdditionalTypesIsAClosure() {
+        assertMacro {
+            """
+            @Instantiable(fulfillingAdditionalTypes: { [AnyObject.self] }())
+            public final class ExampleService {}
+            """
+        } diagnostics: {
+            """
+            @Instantiable(fulfillingAdditionalTypes: { [AnyObject.self] }())
+            ┬───────────────────────────────────────────────────────────────
+            ╰─ 🛑 The argument `fulfillingAdditionalTypes` must be an inlined array
+            public final class ExampleService {}
+            """
+        }
+    }
+
     func test_throwsErrorWhenMoreThanOneForwardedProperty() {
         assertMacro {
             """
@@ -480,7 +514,7 @@ final class InstantiableMacroTests: XCTestCase {
     }
 
 
-    func test_fixit_addsFixitMissingRequiredInitializerWhenLazyConstructedDependencyMissingFromInit() {
+    func test_fixit_addsFixitMissingRequiredInitializerWhenLazyInstantiatedDependencyMissingFromInit() {
         assertMacro {
             """
             @Instantiable
@@ -525,7 +559,7 @@ final class InstantiableMacroTests: XCTestCase {
         }
     }
 
-    func test_fixit_addsFixitMissingRequiredInitializerWhenLazyConstructedAndInstantiatorDependencyOfSameTypeMissingFromInit() {
+    func test_fixit_addsFixitMissingRequiredInitializerWhenLazyInstantiatedAndInstantiatorDependencyOfSameTypeMissingFromInit() {
         assertMacro {
             """
             @Instantiable

Tests/SafeDIPluginTests/SafeDIPluginTests.swift

@@ -61,7 +61,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                 public protocol NetworkService {}
 
-                @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                 public final class DefaultNetworkService: NetworkService {
                     public init() {}
                     let urlSession: URLSession = .shared
@@ -100,7 +100,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                 public protocol NetworkService {}
 
-                @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                 public final class DefaultNetworkService: NetworkService {
                     public init() {}
                     let urlSession: URLSession = .shared
@@ -157,7 +157,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                 public protocol NetworkService {}
 
-                @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                 public final class DefaultNetworkService: NetworkService {
                     public init() {}
                     let urlSession: URLSession = .shared
@@ -214,7 +214,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                 public protocol NetworkService {}
 
-                @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                 public final class DefaultNetworkService: NetworkService {
                     public init() {}
                     let urlSession: URLSession = .shared
@@ -1569,7 +1569,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                     public protocol NetworkService {}
 
-                    @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                    @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                     public final class DefaultNetworkService: NetworkService {
                         public init(urlSession: URLSession) {
                             self.urlSession = urlSession
@@ -1614,7 +1614,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                     public protocol NetworkService {}
 
-                    @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                    @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                     public final class DefaultNetworkService: NetworkService {
                         public init(urlSession: URLSession) {
                             self.urlSession = urlSession
@@ -1751,15 +1751,15 @@ final class SafeDIPluginTests: XCTestCase {
                     """
                     import UIKit
 
-                    @Instantiable(fulfillingAdditionalType: [UIViewController.self])
+                    @Instantiable(fulfillingAdditionalTypes: [UIViewController.self])
                     public final class RootViewController: UIViewController {
                         public init() {}
                     }
                     """,
                     """
                     import UIKit
 
-                    @Instantiable(fulfillingAdditionalType: [UIViewController.self])
+                    @Instantiable(fulfillingAdditionalTypes: [UIViewController.self])
                     public final class SplashViewController: UIViewController {
                         public init() {}
                     }
@@ -1787,7 +1787,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                     public protocol NetworkService {}
 
-                    @Instantiable(fulfillingAdditionalType: [NetworkService.self])
+                    @Instantiable(fulfillingAdditionalTypes: [NetworkService.self])
                     public final class DefaultNetworkService: NetworkService {
                         public init(loggingService: LoggingService) {
                             self.loggingService = loggingService
@@ -1802,7 +1802,7 @@ final class SafeDIPluginTests: XCTestCase {
 
                     public protocol LoggingService {}
 
-                    @Instantiable(fulfillingAdditionalType: [LoggingService.self])
+                    @Instantiable(fulfillingAdditionalTypes: [LoggingService.self])
                     public final class DefaultLoggingService: LoggingService {
                         public init(networkService: NetworkService) {
                             self.networkService = networkService