[Bug] Incorrect swift syntax highlighting for comments

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Link

Monarch playground doesn't encode state into URLs :(

Monaco Editor Playground Code

Copied monarch definitions from https://github.com/microsoft/monaco-editor/blob/main/src/languages/definitions/swift/swift.ts

// Create your own language definition here
// You can safely look at other samples without losing modifications.
// Modifications are not saved on browser refresh/close though -- copy often!
return {
  // Set defaultToken to invalid to see what you do not tokenize yet
  // defaultToken: 'invalid',

  identifier: /[a-zA-Z_][\w$]*/,
  attributes: [
    "@GKInspectable",
    "@IBAction",
    "@IBDesignable",
    "@IBInspectable",
    "@IBOutlet",
    "@IBSegueAction",
    "@NSApplicationMain",
    "@NSCopying",
    "@NSManaged",
    "@Sendable",
    "@UIApplicationMain",
    "@autoclosure",
    "@actorIndependent",
    "@asyncHandler",
    "@available",
    "@convention",
    "@derivative",
    "@differentiable",
    "@discardableResult",
    "@dynamicCallable",
    "@dynamicMemberLookup",
    "@escaping",
    "@frozen",
    "@globalActor",
    "@inlinable",
    "@inline",
    "@main",
    "@noDerivative",
    "@nonobjc",
    "@noreturn",
    "@objc",
    "@objcMembers",
    "@preconcurrency",
    "@propertyWrapper",
    "@requires_stored_property_inits",
    "@resultBuilder",
    "@testable",
    "@unchecked",
    "@unknown",
    "@usableFromInline",
    "@warn_unqualified_access"
  ],
  accessmodifiers: ["open", "public", "internal", "fileprivate", "private"],
  keywords: [
    "#available",
    "#colorLiteral",
    "#column",
    "#dsohandle",
    "#else",
    "#elseif",
    "#endif",
    "#error",
    "#file",
    "#fileID",
    "#fileLiteral",
    "#filePath",
    "#function",
    "#if",
    "#imageLiteral",
    "#keyPath",
    "#line",
    "#selector",
    "#sourceLocation",
    "#warning",
    "Any",
    "Protocol",
    "Self",
    "Type",
    "actor",
    "as",
    "assignment",
    "associatedtype",
    "associativity",
    "async",
    "await",
    "break",
    "case",
    "catch",
    "class",
    "continue",
    "convenience",
    "default",
    "defer",
    "deinit",
    "didSet",
    "do",
    "dynamic",
    "dynamicType",
    "else",
    "enum",
    "extension",
    "fallthrough",
    "false",
    "fileprivate",
    "final",
    "for",
    "func",
    "get",
    "guard",
    "higherThan",
    "if",
    "import",
    "in",
    "indirect",
    "infix",
    "init",
    "inout",
    "internal",
    "is",
    "isolated",
    "lazy",
    "left",
    "let",
    "lowerThan",
    "mutating",
    "nil",
    "none",
    "nonisolated",
    "nonmutating",
    "open",
    "operator",
    "optional",
    "override",
    "postfix",
    "precedence",
    "precedencegroup",
    "prefix",
    "private",
    "protocol",
    "public",
    "repeat",
    "required",
    "rethrows",
    "return",
    "right",
    "safe",
    "self",
    "set",
    "some",
    "static",
    "struct",
    "subscript",
    "super",
    "switch",
    "throw",
    "throws",
    "true",
    "try",
    "typealias",
    "unowned",
    "unsafe",
    "var",
    "weak",
    "where",
    "while",
    "willSet",
    "__consuming",
    "__owned"
  ],
  symbols: /[=(){}\[\].,:;@#\_&\-<>`?!+*\\\/]/,
  // Moved . to operatorstart so it can be a delimiter
  operatorstart: /[\/=\-+!*%<>&|^~?\u00A1-\u00A7\u00A9\u00AB\u00AC\u00AE\u00B0-\u00B1\u00B6\u00BB\u00BF\u00D7\u00F7\u2016-\u2017\u2020-\u2027\u2030-\u203E\u2041-\u2053\u2055-\u205E\u2190-\u23FF\u2500-\u2775\u2794-\u2BFF\u2E00-\u2E7F\u3001-\u3003\u3008-\u3030]/,
  operatorend: /[\u0300-\u036F\u1DC0-\u1DFF\u20D0-\u20FF\uFE00-\uFE0F\uFE20-\uFE2F\uE0100-\uE01EF]/,
  operators: /(@operatorstart)((@operatorstart)|(@operatorend))*/,
  // TODO(owensd): These are borrowed from C#; need to validate correctness for Swift.
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,
  tokenizer: {
    root: [
      { include: "@whitespace" },
      { include: "@comment" },
      { include: "@attribute" },
      { include: "@literal" },
      { include: "@keyword" },
      { include: "@invokedmethod" },
      { include: "@symbol" }
    ],
    whitespace: [
      [/\s+/, "white"],
      [/"""/, "string.quote", "@endDblDocString"]
    ],
    endDblDocString: [
      [/[^"]+/, "string"],
      [/\\"/, "string"],
      [/"""/, "string.quote", "@popall"],
      [/"/, "string"]
    ],
    symbol: [
      [/[{}()\[\]]/, "@brackets"],
      [/[<>](?!@symbols)/, "@brackets"],
      [/[.]/, "delimiter"],
      [/@operators/, "operator"],
      [/@symbols/, "operator"]
    ],
    comment: [
      [/\/\/\/.*$/, "comment.doc"],
      [/\/\*\*/, "comment.doc", "@commentdocbody"],
      [/\/\/.*$/, "comment"],
      [/\/\*/, "comment", "@commentbody"]
    ],
    commentdocbody: [
      [/\/\*/, "comment", "@commentbody"],
      [/\*\//, "comment.doc", "@pop"],
      [/\:[a-zA-Z]+\:/, "comment.doc.param"],
      [/./, "comment.doc"]
    ],
    commentbody: [
      [/\/\*/, "comment", "@commentbody"],
      [/\*\//, "comment", "@pop"],
      [/./, "comment"]
    ],
    attribute: [
      [
        /@@@identifier/,
        {
          cases: {
            "@attributes": "keyword.control",
            "@default": ""
          }
        }
      ]
    ],
    literal: [
      [/"/, { token: "string.quote", next: "@stringlit" }],
      [/0[b]([01]_?)+/, "number.binary"],
      [/0[o]([0-7]_?)+/, "number.octal"],
      [/0[x]([0-9a-fA-F]_?)+([pP][\-+](\d_?)+)?/, "number.hex"],
      [/(\d_?)*\.(\d_?)+([eE][\-+]?(\d_?)+)?/, "number.float"],
      [/(\d_?)+/, "number"]
    ],
    stringlit: [
      [/\\\(/, { token: "operator", next: "@interpolatedexpression" }],
      [/@escapes/, "string"],
      [/\\./, "string.escape.invalid"],
      [/"/, { token: "string.quote", next: "@pop" }],
      [/./, "string"]
    ],
    interpolatedexpression: [
      [/\(/, { token: "operator", next: "@interpolatedexpression" }],
      [/\)/, { token: "operator", next: "@pop" }],
      { include: "@literal" },
      { include: "@keyword" },
      { include: "@symbol" }
    ],
    keyword: [
      [/`/, { token: "operator", next: "@escapedkeyword" }],
      [
        /@identifier/,
        {
          cases: {
            "@keywords": "keyword",
            "[A-Z][a-zA-Z0-9$]*": "type.identifier",
            "@default": "identifier"
          }
        }
      ]
    ],
    escapedkeyword: [
      [/`/, { token: "operator", next: "@pop" }],
      [/./, "identifier"]
    ],
    invokedmethod: [
      [
        /([.])(@identifier)/,
        {
          cases: {
            $2: ["delimeter", "type.identifier"],
            "@default": ""
          }
        }
      ]
    ]
  }
};

Reproduction Steps

With the swift syntax definitions above, type this in the language editor:

/**/
print("This is not a comment")

Actual (Problematic) Behavior

Expected Behavior

The 2nd line shouldn't be highlighted as a comment. Similar to what you get when inserting a space in the comment marker:

Additional Context

The problem is that the commentdocbody regex: [/\/\*\*/, "comment.doc", "@commentdocbody"] is matched eagerly, treating /** as a comment start.

One easy solution would be to add a preceding rule for capturing explicitly /**/. Another would be to add a negative lookahead to the existing commentdocbody regex, but that might be more computationally expensive.