No types produced for record fields when using the legacy protocol

[bwilkerson]

Given the following file:

void f((int, String) r) {
  r.
}

attempting to code complete after the period produces the correct results, but the types of the record fields $1 and $2 are not displayed when using the legacy protocol. (They are produced using LSP.)

[scheglov]

DAS does produce returnType for completions.
See the test.

But apparently IntelliJ does not use it.
@jwren if you want to fix this in IntelliJ.