diff --git a/.editorconfig b/.editorconfig
index d53ca2d35e..5f9188af73 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -756,6 +756,9 @@ dotnet_diagnostic.CA1844.severity = warning
 # Use span-based 'string.Concat'.
 dotnet_diagnostic.CA1845.severity = warning
 
+# Prefer AsSpan over Substring.
+dotnet_diagnostic.CA1846.severity = warning
+
 # Use string.Contains(char) instead of string.Contains(string) with single characters.
 dotnet_diagnostic.CA1847.severity = warning
 
diff --git a/OpenRA.Game/Primitives/Color.cs b/OpenRA.Game/Primitives/Color.cs
index efe18fdba4..3a69a2cde4 100644
--- a/OpenRA.Game/Primitives/Color.cs
+++ b/OpenRA.Game/Primitives/Color.cs
@@ -168,13 +168,13 @@ namespace OpenRA.Primitives
 				return false;
 
 			byte alpha = 255;
-			if (!byte.TryParse(value[0..2], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var red)
-			    || !byte.TryParse(value[2..4], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var green)
-			    || !byte.TryParse(value[4..6], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var blue))
+			if (!byte.TryParse(value.AsSpan(0, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var red)
+			    || !byte.TryParse(value.AsSpan(2, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var green)
+			    || !byte.TryParse(value.AsSpan(4, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var blue))
 				return false;
 
 			if (value.Length == 8
-			    && !byte.TryParse(value[6..8], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out alpha))
+			    && !byte.TryParse(value.AsSpan(6, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out alpha))
 				return false;
 
 			color = FromArgb(alpha, red, green, blue);
diff --git a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
index 0045dcc382..a7b2ecdf13 100644
--- a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
+++ b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
@@ -209,7 +209,7 @@ namespace OpenRA.Platforms.Default
 							var lines = p.StandardOutput.ReadToEnd().Split('\n');
 
 							foreach (var line in lines)
-								if (line.StartsWith("Xft.dpi") && int.TryParse(line[8..], out var dpi))
+								if (line.StartsWith("Xft.dpi") && int.TryParse(line.AsSpan(8), out var dpi))
 									windowScale = dpi / 96f;
 						}
 						catch { }