Description of problem:


    I believe(have tried) we have incorrectly registered TO_CHAR in HSQL dialect:

    org.hibernate.dialect.HSQLDialect:
    registerFunction( "to_char", new StandardSQLFunction( "to_char" ) );

    while org.hibernate.dialect.Oracle8iDialect:
    registerFunction( "to_char", new StandardSQLFunction("to_char",StandardBasicTypes.STRING) );

    We're comparing a TO_CHAR construct that gets a Calendar as parameter to a String. The TO_CHAR converts the Calendar to a String, making it possible to compare it with a String. For me it looks like Hibernate
    doesn't get that TO_CHAR makes that conversion and only sees that there's a Calendar (within the TO_CHAR) on the left hand side and a String parameter on the right hand side and decides (erroneously I think) that a comparison between the two is invalid.


Version-Release number of selected component (if applicable):
- tested in EAP 6.0.1 and 6.1.0 Alpha

How reproducible:
- always

Steps to Reproduce:
Reproducer is attached to the customer's case.

  
Actual results:
Exception thrown.

Expected results:
Query parsed properly.


Additional info:
upstream Jira with proposed patch: https://hibernate.atlassian.net/browse/HHH-8136