This PR removes the recursive checks for nullness conversions. We might need more warnings in the future, but of a much simpler kind, so the best way forward is to restore the code in `Types` and `Check` closer to what's in mainline, and take it from there.
I've left two changes: * the sutyping test from `null` to `Foo!` still fails * a cast from `null` to `Foo!` still fails We might want to detune these as warnings (or not). ------------- Commit messages: - Initial push Changes: https://git.openjdk.org/valhalla/pull/1857/files Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1857&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8374545 Stats: 250 lines in 7 files changed: 3 ins; 206 del; 41 mod Patch: https://git.openjdk.org/valhalla/pull/1857.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1857/head:pull/1857 PR: https://git.openjdk.org/valhalla/pull/1857
