Informix Error -4079: Operation is not allowed in index expressions.

Reasons / Common Causes

-4079 fires when an index expression uses an unsupported operation — per the official guidance, expansion (.*), COPY, NEW, or THRU can't appear inside an index expression.

1. An index expression using .*, COPY, NEW, or THRU, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Remove the unsupported operation from the index expression, computing its value separately if needed before using it as an index.

Examples

An unsupported operation inside an index

LET x = arr[NEW SomeClass]
-- -4079: NEW cannot appear inside an index expression

Corrected

DEFINE obj SomeClass
LET obj = NEW SomeClass
LET x = arr[obj.index]

Diagnostic Checks

1. Check every index expression for .*, COPY, NEW, or THRU, and compute those values outside the index instead.

Related Errors / Related Topics

No closely related error codes are cross-referenced for -4079 in this set yet.

An index expression uses .*, COPY, NEW, or THRU, which aren't allowed there — compute the value separately first.