move ArgumentConversionResult out of SymbolResult

Author: jonsequitur

src/System.CommandLine/Parsing/ArgumentResult.cs

@@ -20,8 +20,8 @@ internal ArgumentResult(
 
         public IArgument Argument { get; }
 
-        internal override ArgumentConversionResult ArgumentConversionResult =>
-            ConversionResult ??= Convert(this, Argument);
+        internal ArgumentConversionResult ArgumentConversionResult =>
+            ConversionResult ??= Convert(Argument);
 
         public override string ToString() => $"{GetType().Name} {Argument.Name}: {string.Join(" ", Tokens.Select(t => $"<{t.Value}>"))}";
 
@@ -40,11 +40,10 @@ internal ParseError CustomError(Argument argument)
             return null;
         }
 
-        internal static ArgumentConversionResult Convert(
-            ArgumentResult argumentResult,
+        internal ArgumentConversionResult Convert(
             IArgument argument)
         {
-            var parentResult = argumentResult.Parent;
+            var parentResult = Parent;
 
             if (ShouldCheckArity() &&
                 ArgumentArity.Validate(parentResult,
@@ -65,12 +64,12 @@ internal static ArgumentConversionResult Convert(
             if (argument is Argument a &&
                 a.ConvertArguments != null)
             {
-                if (argumentResult.ConversionResult != null)
+                if (ConversionResult != null)
                 {
-                    return argumentResult.ConversionResult;
+                    return ConversionResult;
                 }
 
-                var success = a.ConvertArguments(argumentResult, out var value);
+                var success = a.ConvertArguments(this, out var value);
 
                 if (value is ArgumentConversionResult conversionResult)
                 {
@@ -82,7 +81,7 @@ internal static ArgumentConversionResult Convert(
                 }
                 else 
                 {
-                    return ArgumentConversionResult.Failure(argument, argumentResult.ErrorMessage ?? $"Invalid: {parentResult.Token} {string.Join(" ", parentResult.Tokens.Select(t => t.Value))}");
+                    return ArgumentConversionResult.Failure(argument, this.ErrorMessage ?? $"Invalid: {parentResult.Token} {string.Join(" ", parentResult.Tokens.Select(t => t.Value))}");
                 }
             }
 
@@ -104,6 +103,5 @@ bool ShouldCheckArity()
                        optionResult.IsImplicit);
             }
         }
-
     }
 }

src/System.CommandLine/Parsing/CommandResult.cs

@@ -9,6 +9,8 @@ namespace System.CommandLine.Parsing
 {
     public class CommandResult : SymbolResult
     {
+        private ArgumentConversionResultSet _results;
+
         internal CommandResult(
             ICommand command,
             Token token,
@@ -77,5 +79,27 @@ public T ValueForOption<T>(string alias)
                 return default;
             }
         }
+
+        internal ArgumentConversionResultSet ArgumentConversionResults
+        {
+            get
+            {
+                if (_results == null)
+                {
+                    var results = Children
+                                  .OfType<ArgumentResult>()
+                                  .Select(r => r.Convert(r.Argument));
+
+                    _results = new ArgumentConversionResultSet();
+
+                    foreach (var result in results)
+                    {
+                        _results.Add(result);
+                    }
+                }
+
+                return _results;
+            }
+        }
     }
 }

src/System.CommandLine/Parsing/OptionResult.cs

@@ -1,10 +1,15 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System.CommandLine.Binding;
+using System.Linq;
+
 namespace System.CommandLine.Parsing
 {
     public class OptionResult : SymbolResult
     {
+        private ArgumentConversionResult _argumentConversionResult;
+
         internal OptionResult(
             IOption option,
             Token token,
@@ -34,5 +39,23 @@ private protected override int RemainingArgumentCapacity
                 return capacity;
             }
         }
+
+        internal ArgumentConversionResult ArgumentConversionResult
+        {
+            get
+            {
+                if (_argumentConversionResult == null)
+                {
+                    var results = Children
+                                  .OfType<ArgumentResult>()
+                                  .Select(r => r.Convert(r.Argument));
+
+                    _argumentConversionResult = results.SingleOrDefault() ??
+                                                ArgumentConversionResult.None(Option.Argument);
+                }
+
+                return _argumentConversionResult;
+            }
+        }
     }
 }

src/System.CommandLine/Parsing/ParseResultExtensions.cs

@@ -124,7 +124,7 @@ argumentResult.Argument is Argument argument &&
                     builder.Append(" ");
                 }
 
-                switch (symbolResult.ArgumentConversionResult)
+                switch (argumentResult.ArgumentConversionResult)
                 {
                     case SuccessfulArgumentConversionResult successful:
 

src/System.CommandLine/Parsing/SymbolResult.cs

@@ -2,15 +2,13 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Collections.Generic;
-using System.CommandLine.Binding;
 using System.Linq;
 
 namespace System.CommandLine.Parsing
 {
     public abstract class SymbolResult
     {
         private protected readonly List<Token> _tokens = new List<Token>();
-        private ArgumentConversionResultSet _results;
         private ValidationMessages _validationMessages;
         private readonly Dictionary<IArgument, object> _defaultArgumentValues = new Dictionary<IArgument, object>();
 
@@ -26,45 +24,6 @@ private protected SymbolResult(
             Parent = parent;
         }
 
-        internal virtual ArgumentConversionResult ArgumentConversionResult
-        {
-            get
-            {
-                var argument =  Symbol switch {
-                    IOption o => o.Argument,
-                    IArgument a => a,
-                    _ => null
-                };
-
-                return ArgumentConversionResults.SingleOrDefault() ??
-                       ArgumentConversionResult.None(argument);
-            }
-        }
-
-        internal ArgumentConversionResultSet ArgumentConversionResults
-        {
-            get
-            {
-                if (_results == null)
-                {
-                    var results = Children
-                                  .OfType<ArgumentResult>()
-                                  .Select(r => ArgumentResult.Convert(r, r.Argument));
-
-                    _results = new ArgumentConversionResultSet();
-
-                    foreach (var result in results)
-                    {
-                        _results.Add(result);
-                    }
-
-                    return _results;
-                }
-
-                return _results;
-            }
-        }
-
         public string ErrorMessage { get; set; }
 
         public SymbolResultSet Children { get; } = new SymbolResultSet();