diff --git a/.editorconfig b/.editorconfig
index 520a799f94..b0f0d10eb8 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -177,7 +177,10 @@ dotnet_diagnostic.IDE0041.severity = warning
 # Make field readonly.
 dotnet_diagnostic.IDE0044.severity = warning
 
-# Unused private member.
+# Remove unused private member.
+dotnet_diagnostic.IDE0051.severity = warning
+
+# Remove unread private member.
 dotnet_diagnostic.IDE0052.severity = warning
 
 # Unnecessary value assignment.
diff --git a/OpenRA.Game/Graphics/Viewport.cs b/OpenRA.Game/Graphics/Viewport.cs
index a797ea36c4..3dc5d55aa8 100644
--- a/OpenRA.Game/Graphics/Viewport.cs
+++ b/OpenRA.Game/Graphics/Viewport.cs
@@ -121,23 +121,6 @@ namespace OpenRA.Graphics
 		public static long LastMoveRunTime = 0;
 		public static int2 LastMousePos;
 
-		float ClosestTo(float[] collection, float target)
-		{
-			var closestValue = collection.First();
-			var subtractResult = Math.Abs(closestValue - target);
-
-			foreach (var element in collection)
-			{
-				if (Math.Abs(element - target) < subtractResult)
-				{
-					subtractResult = Math.Abs(element - target);
-					closestValue = element;
-				}
-			}
-
-			return closestValue;
-		}
-
 		public ScrollDirection GetBlockedDirections()
 		{
 			var ret = ScrollDirection.None;
diff --git a/OpenRA.Test/OpenRA.Game/VariableExpressionTest.cs b/OpenRA.Test/OpenRA.Game/VariableExpressionTest.cs
index 3c6d03026d..06f778e998 100644
--- a/OpenRA.Test/OpenRA.Game/VariableExpressionTest.cs
+++ b/OpenRA.Test/OpenRA.Game/VariableExpressionTest.cs
@@ -42,11 +42,6 @@ namespace OpenRA.Test
 			Assert.AreEqual(value, new IntegerExpression(expression).Evaluate(testValues), expression);
 		}
 
-		void AssertParseFailure(string expression)
-		{
-			Assert.Throws(typeof(InvalidDataException), () => new IntegerExpression(expression).Evaluate(testValues), expression);
-		}
-
 		void AssertParseFailure(string expression, string errorMessage)
 		{
 			var actualErrorMessage = Assert.Throws(typeof(InvalidDataException),