Ensure casting to typmod -1 generates a RelabelType. Fix the code changed by commit 5c056b0c2 so that we always generate RelabelType, not something else, for a cast to unspecified typmod. Otherwise planner optimizations might not happen.
It appears we missed this point because the previous experiments were done on type numeric: the parser undesirably generates a call on the numeric() length-coercion function, but then numeric_support() optimizes that down to a RelabelType, so that everything seems fine. It misbehaves for types that have a non-optimized length coercion function, such as bpchar. Per report from John Naylor. Back-patch to all supported branches, as the previous patch eventually was. Unfortunately, that no longer includes 9.6 ... we really shouldn't put this type of change into a nearly-EOL branch. Discussion: https://postgr.es/m/cafbsxsefbfhekouc+fsj+3k1shiplpbec67l0sae-9-da8q...@mail.gmail.com Branch ------ REL_11_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/c43d72b245ecfac9fed68363b5c682fc8958bf86 Modified Files -------------- src/backend/parser/parse_coerce.c | 10 ++++++++- src/test/regress/expected/expressions.out | 36 +++++++++++++++++++++++++++++++ src/test/regress/sql/expressions.sql | 16 ++++++++++++++ 3 files changed, 61 insertions(+), 1 deletion(-)
