R: code cleanup

Author: jonsequitur

src/System.CommandLine/ArgumentArity.cs

@@ -30,34 +30,18 @@ public ArgumentArity(int minimumNumberOfValues, int maximumNumberOfValues)
 
         public int MaximumNumberOfValues { get; set; }
 
-        internal static FailedArgumentConversionArityResult Validate(
-            ArgumentResult argumentResult) =>
-            Validate(argumentResult.Parent,
-                     argumentResult.Argument,
-                     argumentResult.Argument.Arity.MinimumNumberOfValues,
-                     argumentResult.Argument.Arity.MaximumNumberOfValues);
-
         internal static FailedArgumentConversionArityResult Validate(
             SymbolResult symbolResult,
             IArgument argument,
             int minimumNumberOfValues,
             int maximumNumberOfValues)
         {
-            SymbolResult argumentResult = null;
-
-            switch (symbolResult)
+            var argumentResult = symbolResult switch
             {
-                case CommandResult commandResult:
-                    argumentResult = commandResult.Root.FindResultFor(argument);
-                    break;
-
-                case OptionResult optionResult:
-                    argumentResult = optionResult.Children.ResultFor(argument);
-                    break;
-
-                case ArgumentResult _:
-                    throw new ArgumentException("");
-            }
+                CommandResult commandResult => commandResult.Root.FindResultFor(argument),
+                OptionResult optionResult => optionResult.Children.ResultFor(argument),
+                _ => symbolResult
+            };
 
             var tokenCount = argumentResult?.Tokens.Count ?? 0;
 

src/System.CommandLine/Parsing/ArgumentResult.cs

@@ -74,14 +74,15 @@ internal virtual ArgumentConversionResult Convert(
                 {
                     return conversionResult;
                 }
-                else if (success)
+
+                if (success)
                 {
                     return ArgumentConversionResult.Success(argument, value);
                 }
-                else 
-                {
-                    return ArgumentConversionResult.Failure(argument, ErrorMessage ?? $"Invalid: {parentResult.Token()} {string.Join(" ", Tokens.Select(t => t.Value))}");
-                }
+
+                return ArgumentConversionResult.Failure(
+                    argument, 
+                    ErrorMessage ?? $"Invalid: {parentResult.Token()} {string.Join(" ", Tokens.Select(t => t.Value))}");
             }
 
             switch (argument.Arity.MaximumNumberOfValues)

src/System.CommandLine/Parsing/SymbolResultExtensions.cs

@@ -24,17 +24,12 @@ internal static IEnumerable<SymbolResult> AllSymbolResults(this SymbolResult sym
             }
         }
 
-        internal static Token Token(this SymbolResult symbolResult)
-        {
-            switch (symbolResult)
+        internal static Token Token(this SymbolResult symbolResult) =>
+            symbolResult switch
             {
-                case CommandResult commandResult:
-                    return commandResult.Token;
-                case OptionResult optionResult:
-                    return optionResult.Token;
-                default:
-                    throw new ArgumentOutOfRangeException(nameof(symbolResult));
-            }
-        }
+                CommandResult commandResult => commandResult.Token,
+                OptionResult optionResult => optionResult.Token,
+                _ => throw new ArgumentOutOfRangeException(nameof(symbolResult))
+            };
     }
 }