Given the recent spate of fixes without issues (and some without even problems), I'd like to propose we change our policy and PR template to require an issue, and advise that the absence of an issue filed and given due discussion may lead to the PR being closed.
Strawman change:
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -8,3 +8,7 @@ The message should end with a reference to the github issue being
addressed in this pull request, e.g. "Fixes #42" to close the linked
issue, or "Partial #42" to indicate that this merge will address it,
but that it isn't ready to be closed yet.
+
+If there is no related issue, please create one first. Without an
+issue and time for discussion, it is unlikely that your pull request
+will be accepted.
Any thoughts in favor or against, or preferred wording?