[CALCITE-1953] Reducing NOT() should not collapse NOT(IS_TRUE) to IS_FALSE for nullable inputs

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.14.0
• Assignee: Julian Hyde
• Reporter: MinJi Kim
• Created: 17/Aug/17 20:58
• Updated: 02/Oct/17 14:30
• Resolved: 29/Aug/17 20:29

Description

In RexSimplify, when simplifying NOT(), we negate the input expression. But for IS_FALSE/IS_TRUE/IS_NOT_FALSE/IS_NOT_TRUE this cannot be just negated if the input is nullable.

IS_FALSE(null) = false
IS_TRUE(null) = false
NOT(IS_FALSE(null)) = true != IS_TRUE(null)

IS_NOT_FALSE(null) = true
IS_NOT_TRUE(null) = true
NOT(IS_NOT_FALSE(null)) = false != IS_NOT_TRUE(null)