code: public Object getSource() {
          Object source = (this.typeProvider != null ? this.typeProvider.getSource() : null);
          return (source != null ? source : this.type);
      }
docs: Return the underlying source of the resolvable type. Will return a {@link Field}, {@link MethodParameter} or {@link Type}
  depending on how the {@link ResolvableType} was constructed. With the exception of the {@link #NONE} constant, this
  method will never return {@code null}. This method is primarily to provide access to additional type information or
  meta-data that alternative JVM languages may provide.