Support SwiftSyntax v601 (#93)

* Support SwiftSyntax v601.

* Run swiftformat

---------

Co-authored-by: Ian Wagner <[email protected]>

Author: scottrhoyt

Package.resolved

@@ -27,7 +27,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/maplibre/maplibre-gl-native-distribution.git", from: "6.10.0"),
         // Macros
-        .package(url: "https://github.com/swiftlang/swift-syntax.git", "509.0.0" ..< "601.0.0"),
+        .package(url: "https://github.com/swiftlang/swift-syntax.git", "509.0.0" ..< "602.0.0"),
         // Testing
         .package(url: "https://github.com/Kolos65/Mockable.git", from: "0.3.1"),
         .package(url: "https://github.com/pointfreeco/swift-snapshot-testing", from: "1.18.3"),

Package.swift

@@ -93,6 +93,21 @@ private func generateFunctionDeclSyntax(identifier: TokenSyntax, valueType: Type
     }
 }
 
+#if canImport(SwiftSyntax601)
+    // This provides compatibility for the new SwiftSyntax API, returning an empty result if the argument has
+    // been parsed as an expression.
+    private func generateStyleProperty(for attributes: AttributeSyntax, valueType: GenericArgumentSyntax.Argument,
+                                       isRawRepresentable: Bool) throws -> [DeclSyntax]
+    {
+        switch valueType {
+        case let .type(type):
+            try generateStyleProperty(for: attributes, valueType: type, isRawRepresentable: isRawRepresentable)
+        default:
+            []
+        }
+    }
+#endif
+
 public struct MLNStylePropertyMacro: MemberMacro {
     public static func expansion(
         of node: AttributeSyntax,