fix #792

Author: jonsequitur

src/System.CommandLine.Tests/ParserTests.MultipleArguments.cs

@@ -119,6 +119,35 @@ public void When_multiple_arguments_are_present_then_their_order_relative_to_sib
                              .Should()
                              .BeTrue();
             }
+
+            [Fact]
+            public void Multiple_arguments_of_unspecified_type_are_parsed_correctly()
+            {
+                var root = new RootCommand
+                {
+                    new Argument("source")
+                    {
+                        Arity = ArgumentArity.ExactlyOne
+                    },
+                    new Argument("destination")
+                    {
+                        Arity = ArgumentArity.ExactlyOne
+                    }
+                };
+
+                var result = root.Parse("src.txt", "dest.txt");
+
+                result.RootCommandResult
+                      .GetArgumentValueOrDefault("source")
+                      .Should()
+                      .Be("src.txt");
+                
+                result.RootCommandResult
+                      .GetArgumentValueOrDefault("destination")
+                      .Should()
+                      .Be("dest.txt");
+            }
+
         }
     }
 }

src/System.CommandLine/Parsing/ArgumentResult.cs

@@ -80,7 +80,7 @@ internal virtual ArgumentConversionResult Convert(
                 }
                 else 
                 {
-                    return ArgumentConversionResult.Failure(argument, ErrorMessage ?? $"Invalid: {parentResult.Token()} {string.Join(" ", parentResult.Tokens.Select(t => t.Value))}");
+                    return ArgumentConversionResult.Failure(argument, ErrorMessage ?? $"Invalid: {parentResult.Token()} {string.Join(" ", Tokens.Select(t => t.Value))}");
                 }
             }
 
@@ -90,10 +90,14 @@ internal virtual ArgumentConversionResult Convert(
                     return ArgumentConversionResult.Success(argument, null);
 
                 case 1:
-                    return ArgumentConversionResult.Success(argument, parentResult.Tokens.Select(t => t.Value).SingleOrDefault());
+                    return ArgumentConversionResult.Success(
+                        argument, 
+                        Tokens.Select(t => t.Value).SingleOrDefault());
 
                 default:
-                    return ArgumentConversionResult.Success(argument, parentResult.Tokens.Select(t => t.Value).ToArray());
+                    return ArgumentConversionResult.Success(
+                        argument, 
+                        Tokens.Select(t => t.Value).ToArray());
             }
 
             bool ShouldCheckArity()