Added static code analyzer, and fixed the code in regards to the recommendations in the GeoJSON.Text project

Author: Martin Boje Carpentier

src/GeoJSON.Text.Test.Unit/Feature/FeatureTests.cs

@@ -462,7 +462,7 @@ public void Feature_Equals_All_Geometry_Null_Issue115()
         }
 
 
-        private IGeometryObject GetGeometry()
+        private static IGeometryObject GetGeometry()
         {
             var coordinates = new List<LineString>
             {

src/GeoJSON.Text/Feature/Feature.cs

@@ -143,7 +143,7 @@ public TProps Properties {
         /// <returns></returns>
         public bool Equals(Feature<TGeometry, TProps> other)
         {
-            if (ReferenceEquals(null, other)) return false;
+            if (other is null) return false;
             if (ReferenceEquals(this, other)) return true;
             return base.Equals(other)
                    && string.Equals(Id, other.Id)
@@ -153,7 +153,7 @@ public bool Equals(Feature<TGeometry, TProps> other)
 
         public override bool Equals(object obj)
         {
-            if (ReferenceEquals(null, obj)) return false;
+            if (obj is null) return false;
             if (ReferenceEquals(this, obj)) return true;
             if (obj.GetType() != GetType()) return false;
             return Equals((Feature<TGeometry, TProps>) obj);
@@ -306,7 +306,7 @@ public override int GetHashCode()
 
         public static bool operator ==(Feature<TGeometry> left, Feature<TGeometry> right)
         {
-            return left?.Equals(right) ?? ReferenceEquals(null, right);
+            return left?.Equals(right) ?? right is null;
         }
 
         public static bool operator !=(Feature<TGeometry> left, Feature<TGeometry> right)

src/GeoJSON.Text/GeoJSON.Text.csproj

@@ -15,6 +15,7 @@
 		<PackageTags>geojson;geo;json;geolocation</PackageTags>
 		<PackageLicenseExpression>MIT</PackageLicenseExpression>
 		<PackageReleaseNotes></PackageReleaseNotes>
+		<EnableNETAnalyzers>true</EnableNETAnalyzers>
 
 		<IncludeSymbols>true</IncludeSymbols>
 		<SymbolPackageFormat>snupkg</SymbolPackageFormat>
@@ -31,6 +32,10 @@
 	</PropertyGroup>	
 
 	<ItemGroup>
+		<PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="6.0.0">
+		  <PrivateAssets>all</PrivateAssets>
+		  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+		</PackageReference>
 		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />
 		<PackageReference Include="System.Text.Json" Version="6.0.1" />
 	</ItemGroup>

src/GeoJSON.Text/GeoJSONObject.cs

@@ -86,7 +86,7 @@ public bool Equals(GeoJSONObject left, GeoJSONObject right)
             {
                 return true;
             }
-            if (ReferenceEquals(null, right))
+            if (right is null)
             {
                 return false;
             }
@@ -101,8 +101,8 @@ public bool Equals(GeoJSONObject left, GeoJSONObject right)
                 return false;
             }
 
-            var leftIsNull = ReferenceEquals(null, left.BoundingBoxes);
-            var rightIsNull = ReferenceEquals(null, right.BoundingBoxes);
+            var leftIsNull = left.BoundingBoxes is null;
+            var rightIsNull = right.BoundingBoxes is null;
             var bothAreMissing = leftIsNull && rightIsNull;
 
             if (bothAreMissing || leftIsNull != rightIsNull)
@@ -122,7 +122,7 @@ public bool Equals(GeoJSONObject left, GeoJSONObject right)
             {
                 return true;
             }
-            if (ReferenceEquals(null, right))
+            if (right is null)
             {
                 return false;
             }

src/GeoJSON.Text/Geometry/GeometryCollection.cs

@@ -20,7 +20,7 @@ public class GeometryCollection : GeoJSONObject, IGeometryObject, IEqualityCompa
         /// <summary>
         /// Initializes a new instance of the <see cref="GeometryCollection" /> class.
         /// </summary>
-        public GeometryCollection() : this(new IGeometryObject[0])
+        public GeometryCollection() : this(new Array.Empty[0])
         {
         }
 

src/GeoJSON.Text/Geometry/MultiLineString.cs

@@ -30,7 +30,7 @@ public MultiLineString()
         public MultiLineString(IEnumerable<LineString> coordinates)
         {
             Coordinates =new ReadOnlyCollection<LineString>(
-                coordinates?.ToArray() ?? new LineString[0]);
+                coordinates?.ToArray() ?? Array.Empty<LineString>());
         }
 
         /// <summary>

src/GeoJSON.Text/Geometry/MultiPoint.cs

@@ -28,7 +28,7 @@ public MultiPoint()
         /// <param name="coordinates">The coordinates.</param>
         public MultiPoint(IEnumerable<Point> coordinates)
         {
-            Coordinates = new ReadOnlyCollection<Point>(coordinates?.ToArray() ?? new Point[0]);
+            Coordinates = new ReadOnlyCollection<Point>(coordinates?.ToArray() ?? Array.Empty<Point>());
         }
 
         //[JsonConstructor]

src/GeoJSON.Text/Geometry/Position.cs

@@ -135,7 +135,7 @@ public bool Equals(Position left, Position right)
             {
                 return true;
             }
-            if (ReferenceEquals(null, right) || ReferenceEquals(null, left))
+            if (right is null || left is null)
             {
                 return false;
             }