Hello.
Right now, Calcite allows to cast FLOAT, DOUBLE expressions to BOOLEAN.
But, results is always `false`. Cast works as `java.lang.Boolean.parseBoolean`
call and always return false for anything except «true»
string(`Primitive#parse`).
Simple additional test for `InterpreterTest` shows this:
```
@Test void testDoubleCast() {
sql("SELECT CAST(CAST('0.0' AS DOUBLE) AS BOOLEAN)").returnsRows("[false]");
sql("SELECT CAST(CAST('0.1' AS DOUBLE) AS BOOLEAN)").returnsRows("[false]");
sql("SELECT CAST(CAST('1.0' AS DOUBLE) AS BOOLEAN)").returnsRows("[false]");
sql("SELECT CAST(CAST('42' AS DOUBLE) AS BOOLEAN)").returnsRows("[false]");
}
```
Other database, such as Postgres, disallow cast from double(float) to boolean:
```
psql (14.6 (Homebrew))
Type "help" for help.
postgres=# SELECT CAST(CAST('1' AS float) AS BOOLEAN);
ERROR: cannot cast type double precision to boolean
LINE 1: SELECT CAST(CAST('1' AS float) AS BOOLEAN);
^
postgres=#
```
Do we really need to support this?
I think Calcite should disallow this kind of conversion for better user
experience.
I can provide PR to implement proposed behavior
What do you think?
