Sightly improve variable naming of known types such as EventArgs and Exceptions

Author: siegfriedpammer

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/GuessAccessors.cs

@@ -50,9 +50,9 @@ public void MethodUnknownGenericClass()
 			//IL_00e1: Expected O, but got Unknown
 			//IL_00e1: Expected O, but got Unknown
 			UnknownGenericClass<UnknownEventArgs> val = new UnknownGenericClass<UnknownEventArgs>();
-			UnknownEventArgs val2 = (val.UnknownProperty = val.UnknownProperty);
+			UnknownEventArgs e = (val.UnknownProperty = val.UnknownProperty);
 			List<object> list = new List<object> {
-				val[((object)val2).GetHashCode()] ?? "",
+				val[((object)e).GetHashCode()] ?? "",
 				val.NotProperty,
 				val.get_NotPropertyWithGeneric<string>(42),
 				val[42],
@@ -61,10 +61,10 @@ public void MethodUnknownGenericClass()
 			};
 			val.OnEvent += Instance_OnEvent;
 			val.OnEvent -= Instance_OnEvent;
-			UnknownEventArgs val3 = val[(UnknownEventArgs)null];
-			val[new UnknownEventArgs()] = val3;
-			UnknownEventArgs val4 = val[new UnknownEventArgs(), new UnknownEventArgs()];
-			val[new UnknownEventArgs(), new UnknownEventArgs()] = val4;
+			UnknownEventArgs e2 = val[(UnknownEventArgs)null];
+			val[new UnknownEventArgs()] = e2;
+			UnknownEventArgs e3 = val[new UnknownEventArgs(), new UnknownEventArgs()];
+			val[new UnknownEventArgs(), new UnknownEventArgs()] = e3;
 		}
 
 		public void MethodUnknownStatic()

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

@@ -418,9 +418,9 @@ public void GenericException<TException>(int input) where TException : Exception
 			{
 				Console.WriteLine(input);
 			}
-			catch (TException val)
+			catch (TException ex)
 			{
-				Console.WriteLine(val.Message);
+				Console.WriteLine(ex.Message);
 				throw;
 			}
 		}
@@ -452,9 +452,9 @@ public void GenericExceptionWithCondition<TException>(int input) where TExceptio
 			{
 				Console.WriteLine(input);
 			}
-			catch (TException val) when (val.Message.Contains("Test"))
+			catch (TException ex) when (ex.Message.Contains("Test"))
 			{
-				Console.WriteLine(val.Message);
+				Console.WriteLine(ex.Message);
 				throw;
 			}
 		}
@@ -465,9 +465,9 @@ public void GenericException2WithCondition<TException>(int input) where TExcepti
 			{
 				Console.WriteLine(input);
 			}
-			catch (TException val) when (val.Message.Contains("Test"))
+			catch (TException ex) when (ex.Message.Contains("Test"))
 			{
-				Console.WriteLine("{0} {1}", val, val.ToString());
+				Console.WriteLine("{0} {1}", ex, ex.ToString());
 			}
 		}
 

ICSharpCode.Decompiler/IL/Transforms/AssignVariableNames.cs

@@ -729,22 +729,7 @@ static string GetNameByType(IType type)
 				type = NullableType.GetUnderlyingType(((TypeWithElementType)type).ElementType);
 			}
 
-			string name = type.Kind switch {
-				TypeKind.Array => "array",
-				TypeKind.Pointer => "ptr",
-				TypeKind.TypeParameter => "val",
-				TypeKind.Unknown => "val",
-				TypeKind.Dynamic => "val",
-				TypeKind.ByReference => "reference",
-				TypeKind.Tuple => "tuple",
-				TypeKind.NInt => "num",
-				TypeKind.NUInt => "num",
-				_ => null
-			};
-			if (name != null)
-			{
-				return name;
-			}
+			string name;
 			if (type.IsAnonymousType())
 			{
 				name = "anon";
@@ -753,13 +738,28 @@ static string GetNameByType(IType type)
 			{
 				name = "ex";
 			}
+			else if (type.Name.EndsWith("EventArgs", StringComparison.Ordinal))
+			{
+				name = "e";
+			}
 			else if (type.IsCSharpNativeIntegerType())
 			{
 				name = "num";
 			}
 			else if (!typeNameToVariableNameDict.TryGetValue(type.FullName, out name))
 			{
-				name = type.Name;
+				name = type.Kind switch {
+					TypeKind.Array => "array",
+					TypeKind.Pointer => "ptr",
+					TypeKind.TypeParameter => "val",
+					TypeKind.Unknown => "val",
+					TypeKind.Dynamic => "val",
+					TypeKind.ByReference => "reference",
+					TypeKind.Tuple => "tuple",
+					TypeKind.NInt => "num",
+					TypeKind.NUInt => "num",
+					_ => type.Name
+				};
 				// remove the 'I' for interfaces
 				if (name.Length >= 3 && name[0] == 'I' && char.IsUpper(name[1]) && char.IsLower(name[2]))
 					name = name.Substring(1);