Fix #2646: Missing values for enums with skipped or duplicate items

ICSharpCode.Decompiler.Tests/TestCases/Pretty/EnumTests.cs

@@ -34,6 +34,20 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 			Item0 = 0
 		}
 
+		public enum EnumSkippedItemTest
+		{
+			Item0 = 0,
+			Item2 = 2
+		}
+
+		public enum EnumDuplicateItemTest
+		{
+			Item0 = 0,
+			Item1 = 1,
+			Item2A = 2,
+			Item2B = 2
+		}
+
 		public enum LongBasedEnum : long
 		{
 			Item1,

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -1405,12 +1405,12 @@ namespace ICSharpCode.Decompiler.CSharp
 					firstValue = currentValue;
 					first = false;
 				}
-				else if (currentValue < previousValue)
+				else if (currentValue <= previousValue)
 				{
 					// If the values are out of order, we fallback to displaying all values.
 					return EnumValueDisplayMode.All;
 				}
-				else if ((!allConsecutive && !allPowersOfTwo))
+				else if (!allConsecutive && !allPowersOfTwo)
 				{
 					// We already know that the values are neither consecutive nor all powers of 2,
 					// so we can abort, and just display all values as-is.
@@ -1418,10 +1418,18 @@ namespace ICSharpCode.Decompiler.CSharp
 				}
 				previousValue = currentValue;
 			}
-			if (allPowersOfTwo && previousValue > 2)
+			if (allPowersOfTwo)
 			{
-				// If all values are powers of 2, display all enum values, but use hex.
+				if (previousValue > 8)
-				return EnumValueDisplayMode.AllHex;
+				{
+					// If all values are powers of 2 and greater 8, display all enum values, but use hex.
+					return EnumValueDisplayMode.AllHex;
+				}
+				else if (!allConsecutive)
+				{
+					// If all values are powers of 2, display all enum values.
+					return EnumValueDisplayMode.All;
+				}
 			}
 			if (settings.AlwaysShowEnumMemberValues)
 			{