DTS tests broken

[waynevanson]

🐛 Bug report

Current Behavior

Here is a small excerpt. Looks like the union is mapped incorrectly for only the first to types in a union.

ERROR: 99:1   expect  Expected type to be:
  Record<"a" | "b" | "c", number>
got:
  Record<"b" | "a" | "c", number>

Expected behavior

No errors, branch has been pulled straight from master.

Reproducible example

git clone git@github.com:gcanti/fp-ts.git
cd fp-ts
npm i
npm test

Suggested solution(s)

Not sure.

Additional context

Causes multiple PR's in CI to fail,
Fails locally

Your environment

branch master with node@12

[gcanti]

@waynevanson thanks for the bug report