[ 
https://issues.apache.org/jira/browse/CALCITE-2615?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Julian Hyde updated CALCITE-2615:
---------------------------------
    Description: 
When simplifying NOT-AND-OR, RexSimplify incorrectly applies predicates deduced 
for operands to the same operands.

Here is the test case (add it to RexProgramTest):
{code:java}
  @Test public void testSimplifyNotAnd() {
    final RexNode e = not(
        and(
            gt(and(vBool(1), literal(true)),
                or(literal(true), literal(true), literal(false))),
            gt(isNotNull(vBool(0)), eq(literal(false), vBool(1))),
            or(ne(literal(true), literal(false)),
                ge(vInt(0), literal((Integer) null)))));
    final String expected = "TODO";
   checkSimplify(e, expected);
  }
{code}
When you run it, verify will find a combination of assignments such that the 
simplified expression returns a different result than the original.

The test case is not minimal; sorry. Maybe it reproduces with NOT-OR.

The bug is in 
[RexSimplify.simplifyAndTerms|https://github.com/apache/calcite/blob/6b3844c0634792263a5073b8ea93565fb3415f41/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L412].
 Put a breakpoint at that line to see the problem. It passes through the 
operands once, building a list of predicates. Then it passes through the 
operands again, simplifying each operand. Thus operand1 is simplified using a 
list of predicates that includes the predicate 'not operand1'. Clearly wrong. 
[~kgyrtkirk], I warned that this was possible in our discussions.

  was:
When simplifying NOT AND, RexSimplify incorrectly applies predicates deduced 
for operands to the same operands.

Here is the test case (add it to RexProgramTest):
{code}
  @Test public void testSimplifyNotAnd() {
    final RexNode e = not(
        and(
            gt(and(vBool(1), literal(true)),
                or(literal(true), literal(true), literal(false))),
            gt(isNotNull(vBool(0)), eq(literal(false), vBool(1))),
            or(ne(literal(true), literal(false)),
                ge(vInt(0), literal((Integer) null)))));
    final String expected = "TODO";
   checkSimplify(e, expected);
  }
{code}

When you run it, verify will find a combination of assignments such that the 
simplified expression returns a different result than the original.

The test case is not minimal; sorry.

The bug is in 
[RexSimplify.simplifyAndTerms|https://github.com/apache/calcite/blob/6b3844c0634792263a5073b8ea93565fb3415f41/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L412].
 Put a breakpoint at that line to see the problem. It passes through the 
operands once, building a list of predicates. Then it passes through the 
operands again, simplifying each operand. Thus operand1 is simplified using a 
list of predicates that includes the predicate 'not operand1'. Clearly wrong. 
[~kgyrtkirk], I warned that this was possible in our discussions.


> When simplifying NOT-AND-OR, RexSimplify incorrectly applies predicates 
> deduced for operands to the same operands
> -----------------------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-2615
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2615
>             Project: Calcite
>          Issue Type: Task
>            Reporter: Julian Hyde
>            Assignee: Julian Hyde
>            Priority: Major
>
> When simplifying NOT-AND-OR, RexSimplify incorrectly applies predicates 
> deduced for operands to the same operands.
> Here is the test case (add it to RexProgramTest):
> {code:java}
>   @Test public void testSimplifyNotAnd() {
>     final RexNode e = not(
>         and(
>             gt(and(vBool(1), literal(true)),
>                 or(literal(true), literal(true), literal(false))),
>             gt(isNotNull(vBool(0)), eq(literal(false), vBool(1))),
>             or(ne(literal(true), literal(false)),
>                 ge(vInt(0), literal((Integer) null)))));
>     final String expected = "TODO";
>    checkSimplify(e, expected);
>   }
> {code}
> When you run it, verify will find a combination of assignments such that the 
> simplified expression returns a different result than the original.
> The test case is not minimal; sorry. Maybe it reproduces with NOT-OR.
> The bug is in 
> [RexSimplify.simplifyAndTerms|https://github.com/apache/calcite/blob/6b3844c0634792263a5073b8ea93565fb3415f41/core/src/main/java/org/apache/calcite/rex/RexSimplify.java#L412].
>  Put a breakpoint at that line to see the problem. It passes through the 
> operands once, building a list of predicates. Then it passes through the 
> operands again, simplifying each operand. Thus operand1 is simplified using a 
> list of predicates that includes the predicate 'not operand1'. Clearly wrong. 
> [~kgyrtkirk], I warned that this was possible in our discussions.



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