required validation errors show json instance location

Author: klundberg

Package.swift

@@ -5,7 +5,7 @@ import PackageDescription
 let package = Package(
   name: "JSONSchema",
   platforms: [
-    .macOS(.v10_13),
+    .macOS(.v10_13), .iOS(.v11), .tvOS(.v11)
   ],
   products: [
     .library(name: "JSONSchema", targets: ["JSONSchema"]),

Sources/Validation/required.swift

@@ -10,6 +10,8 @@ func required(context: Context, required: Any, instance: Any, schema: [String: A
 
   return AnySequence(required.compactMap { key -> ValidationError? in
     guard !instance.keys.contains(key) else { return nil }
+    context.instanceLocation.push(key)
+    defer { context.instanceLocation.pop() }
     return ValidationError(
       "Required property '\(key)' is missing",
       instanceLocation: context.instanceLocation,