Fix bug where a JSON value can't match an earlier key

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test/LightJson/JsonReaderTests.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
+// Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
+
+namespace StyleCop.Analyzers.Test.LightJson
+{
+    using global::LightJson;
+    using global::LightJson.Serialization;
+    using Xunit;
+
+    public class JsonReaderTests
+    {
+        [Fact]
+        public void TestKeyMatchesPreviousValue()
+        {
+            var jsonObject = JsonValue.Parse("{ \"x\": \"value\", \"value\": \"value\" }");
+            Assert.NotNull(jsonObject);
+            Assert.Equal("value", jsonObject["x"].AsString);
+            Assert.Equal("value", jsonObject["value"].AsString);
+            Assert.Equal(jsonObject["x"], jsonObject["value"]);
+        }
+
+        [Fact]
+        public void TestDuplicateKeys()
+        {
+            Assert.ThrowsAny<JsonParseException>(() => JsonValue.Parse("{ \"x\": \"value\", \"x\": \"value\" }"));
+        }
+    }
+}

StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj

@@ -235,6 +235,7 @@
     <Compile Include="LayoutRules\SA1518UnitTests.cs" />
     <Compile Include="LayoutRules\SA1519UnitTests.cs" />
     <Compile Include="LayoutRules\SA1520UnitTests.cs" />
+    <Compile Include="LightJson\JsonReaderTests.cs" />
     <Compile Include="LightJson\JsonValueTests.cs" />
     <Compile Include="Lightup\AccessorDeclarationSyntaxExtensionsTests.cs" />
     <Compile Include="Lightup\AutoWrapSeparatedSyntaxListTests.cs" />

StyleCop.Analyzers/StyleCop.Analyzers/LightJson/Serialization/JsonReader.cs

@@ -344,7 +344,7 @@ private JsonObject ReadObject(JsonObject jsonObject)
 
                     var key = this.ReadJsonKey();
 
-                    if (jsonObject.Contains(key))
+                    if (jsonObject.ContainsKey(key))
                     {
                         throw new JsonParseException(
                             ErrorType.DuplicateObjectKeys,