julianhyde commented on a change in pull request #2144:
URL: https://github.com/apache/calcite/pull/2144#discussion_r485806842
##########
File path: core/src/main/java/org/apache/calcite/rex/RexSimplify.java
##########
@@ -2690,7 +2691,14 @@ int complexity() {
}
@Override public RelDataType getType() {
- return rexBuilder.typeFactory.leastRestrictive(Util.distinctList(types));
+ if (this.types.isEmpty()) {
+ // Expression is "x IS NULL"
+ return ref.getType();
Review comment:
I agree it's a bit strange. It's tricky because the assignment rules for
the left-hand type are different from the right-hand types.
The type assignment rules are complicated (e.g. when you compare a REAL to a
DECIMAL, do you convert the REAL to a DECIMAL or vice versa?; and hundred other
things. I decided to not spend effort addressing it at this point. If you can
find a SQL example where it matters, log a bug.
##########
File path: core/src/main/java/org/apache/calcite/rex/RexSimplify.java
##########
@@ -2690,7 +2691,14 @@ int complexity() {
}
@Override public RelDataType getType() {
- return rexBuilder.typeFactory.leastRestrictive(Util.distinctList(types));
+ if (this.types.isEmpty()) {
+ // Expression is "x IS NULL"
+ return ref.getType();
Review comment:
I agree it's a bit strange. It's tricky because the assignment rules for
the left-hand type are different from the right-hand types.
The type assignment rules are complicated (e.g. when you compare a REAL to a
DECIMAL, do you convert the REAL to a DECIMAL or vice versa?; and hundred other
things). I decided to not spend effort addressing it at this point. If you
can find a SQL example where it matters, log a bug.
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