account for scalar arguments

Author: jonsequitur

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

@@ -256,6 +256,47 @@ public void Leading_known_option_is_parsed_normally_when_capture_is_first_argume
                 result.GetValue(toolArgs).Should().BeEquivalentSequenceTo("foo", "--unknown");
                 result.Errors.Should().BeEmpty();
             }
+
+            [Fact]
+            public void Scalar_capture_escapes_one_token_then_resumes_normal_parsing()
+            {
+                var verbose = new Option<bool>("--verbose");
+                var first = new Argument<string>("first");
+                var target = new Argument<string>("target") { CaptureRemainingTokens = true };
+                var command = new RootCommand
+                {
+                    verbose,
+                    first,
+                    target
+                };
+
+                var result = command.Parse("foo --verbose --verbose");
+
+                using var _ = new AssertionScope();
+                result.GetValue(first).Should().Be("foo");
+                result.GetValue(target).Should().Be("--verbose");
+                result.GetValue(verbose).Should().BeTrue();
+                result.Errors.Should().BeEmpty();
+            }
+
+            [Fact]
+            public void Options_after_scalar_capture_overflow_are_parsed_normally()
+            {
+                var verbose = new Option<bool>("--verbose");
+                var target = new Argument<string>("target") { CaptureRemainingTokens = true };
+                var command = new RootCommand
+                {
+                    verbose,
+                    target
+                };
+
+                var result = command.Parse("hello --verbose");
+
+                using var _ = new AssertionScope();
+                result.GetValue(target).Should().Be("hello");
+                result.GetValue(verbose).Should().BeTrue();
+                result.Errors.Should().BeEmpty();
+            }
         }
     }
 }

src/System.CommandLine/Parsing/ParseOperation.cs

@@ -194,6 +194,13 @@ private void ParseCommandArguments(ref int currentArgumentCount, ref int current
 
                 if (currentArgumentCount == 0) // no matching arguments found
                 {
+                    if (captureRemaining)
+                    {
+                        // Return to ParseCommandChildren so that overflow tokens
+                        // are dispatched normally (e.g. as options or subcommands).
+                        break;
+                    }
+
                     AddCurrentTokenToUnmatched();
                     Advance();
                 }