NOTE: This PR was created with AI tools and a human.

When evaluating 'x IN []' with an empty list, the transform_AEXPR_IN
function would return NULL because no expressions were processed.
This caused a 'cache lookup failed for type 0' error downstream.

This fix adds an early check for the empty list case:
- 'x IN []' returns false (nothing can be in an empty list)

Additional NOTE: Cypher does not have 'NOT IN' syntax. To check if
a value is NOT in a list, use 'NOT (x IN list)'. The NOT operator
will invert the false from an empty list to true as expected.

The fix returns a boolean constant directly, avoiding the NULL result
that caused the type lookup failure.

Added regression tests.

modified:   regress/expected/expr.out
modified:   regress/sql/expr.sql
modified:   src/backend/parser/cypher_expr.c

NOTE: This PR was created with AI tools and a human.

When evaluating 'x IN []' with an empty list, the transform_AEXPR_IN
function would return NULL because no expressions were processed.
This caused a 'cache lookup failed for type 0' error downstream.

This fix adds an early check for the empty list case:
- 'x IN []' returns false (nothing can be in an empty list)

Additional NOTE: Cypher does not have 'NOT IN' syntax. To check if
a value is NOT in a list, use 'NOT (x IN list)'. The NOT operator
will invert the false from an empty list to true as expected.

The fix returns a boolean constant directly, avoiding the NULL result
that caused the type lookup failure.

Added regression tests.

modified:   regress/expected/expr.out
modified:   regress/sql/expr.sql
modified:   src/backend/parser/cypher_expr.c

NOTE: This PR was created with AI tools and a human.

When evaluating 'x IN []' with an empty list, the transform_AEXPR_IN
function would return NULL because no expressions were processed.
This caused a 'cache lookup failed for type 0' error downstream.

This fix adds an early check for the empty list case:
- 'x IN []' returns false (nothing can be in an empty list)

Additional NOTE: Cypher does not have 'NOT IN' syntax. To check if
a value is NOT in a list, use 'NOT (x IN list)'. The NOT operator
will invert the false from an empty list to true as expected.

The fix returns a boolean constant directly, avoiding the NULL result
that caused the type lookup failure.

Added regression tests.

modified:   regress/expected/expr.out
modified:   regress/sql/expr.sql
modified:   src/backend/parser/cypher_expr.c

NOTE: This PR was created with AI tools and a human.

When evaluating 'x IN []' with an empty list, the transform_AEXPR_IN
function would return NULL because no expressions were processed.
This caused a 'cache lookup failed for type 0' error downstream.

This fix adds an early check for the empty list case:
- 'x IN []' returns false (nothing can be in an empty list)

Additional NOTE: Cypher does not have 'NOT IN' syntax. To check if
a value is NOT in a list, use 'NOT (x IN list)'. The NOT operator
will invert the false from an empty list to true as expected.

The fix returns a boolean constant directly, avoiding the NULL result
that caused the type lookup failure.

Added regression tests.

modified:   regress/expected/expr.out
modified:   regress/sql/expr.sql
modified:   src/backend/parser/cypher_expr.c

NOTE: This PR was created with AI tools and a human.

When evaluating 'x IN []' with an empty list, the transform_AEXPR_IN
function would return NULL because no expressions were processed.
This caused a 'cache lookup failed for type 0' error downstream.

This fix adds an early check for the empty list case:
- 'x IN []' returns false (nothing can be in an empty list)

Additional NOTE: Cypher does not have 'NOT IN' syntax. To check if
a value is NOT in a list, use 'NOT (x IN list)'. The NOT operator
will invert the false from an empty list to true as expected.

The fix returns a boolean constant directly, avoiding the NULL result
that caused the type lookup failure.

Added regression tests.

modified:   regress/expected/expr.out
modified:   regress/sql/expr.sql
modified:   src/backend/parser/cypher_expr.c