E0263: only one comma is allowed between or after generic parameters

In a TypeScript generic class, function, or type alias, the generic parameter list is a comma-separated list of variables surrounded by < and >. It is a syntax error for the parameter list to have doubled commas:

class HashMap<Key, , Hasher> {
  // ...
}

function makeHashMap<Key,, Value>(
): HashMap<Key, Value, DefaultHasher> {
  return new HashMap(new DefaultHasher());
}

To fix this error, write a type variable name between the commas:

class HashMap<Key, Value, Hasher> {
  // ...
}

Alternatively, remove the extra comma:

function makeHashMap<Key, Value>(
): HashMap<Key, Value, DefaultHasher> {
  return new HashMap(new DefaultHasher());
}

Introduced in quick-lint-js version 2.8.0.

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