code: public JSType getType(
        StaticTypedScope scope, String jsTypeName, String sourceName, int lineno, int charno) {
      return getType(scope, jsTypeName, sourceName, lineno, charno, true);
    }
docs: Looks up a type by name. To allow for forward references to types, an unrecognized string has
  to be bound to a NamedType object that will be resolved later.
  
  @param scope A scope for doing type name resolution.
  @param jsTypeName The name string.
  @param sourceName The name of the source file where this reference appears.
  @param lineno The line number of the reference.
  @return a NamedType if the string argument is not one of the known types, otherwise the
  corresponding JSType object.