The addition of `addDeclErr` introduced a memory leak at every call
site, and I also would like to push back on having more than 1
compilation error per `Decl`.
This reverts commit 1634d45f1d53c8d7bfefa56ab4d2fa4cc8218b6d.
f75d4cbe56Andrew Kelley committed on 12/28/2020, 6:24:53 PMparent7ed499e