What causes "Ambiguous negation: use type casts to disambiguate" in apache/cassandra?

Cast the operand explicitly: SELECT -(int) col FROM t or -(double) col FROM t

apache/cassandra · error · InvalidRequestException

Ambiguous negation: use type casts to disambiguate

Error message

Ambiguous negation: use type casts to disambiguate

What it means

Specific to the unary negation operator (-). FunctionResolver found multiple compatible signatures for negating a value (e.g. the operand's type can coerce to both int and float negation overloads) and no type hint exists, so it throws a targeted message instead of the generic ambiguous-call error, instructing the developer to use explicit type casts.

Source

Thrown at src/java/org/apache/cassandra/cql3/functions/FunctionResolver.java:185

        if (compatibles.size() > 1)
        {
            if (OperationFcts.isOperation(name))
            {
                if (receiverType != null && !containsMarkers(providedArgs))
                {
                    for (Function toTest : compatibles)
                    {
                        List<AbstractType<?>> argTypes = toTest.argTypes();
                        if (receiverType.equals(argTypes.get(0)) && receiverType.equals(argTypes.get(1)))
                            return toTest;
                    }
                }
                throw invalidRequest("Ambiguous '%s' operation with args %s and %s: use type hint to disambiguate, example '(int) ?'",
                                     OperationFcts.getOperator(name), providedArgs.get(0), providedArgs.get(1));
            }

            if (OperationFcts.isNegation(name))
                throw invalidRequest("Ambiguous negation: use type casts to disambiguate");

            throw invalidRequest("Ambiguous call to function %s (can be matched by following signatures: %s): use type casts to disambiguate",
                                 name, format(compatibles));
        }

        return compatibles.get(0);
    }

    /**
     * Checks if at least one of the specified arguments is a marker.
     *
     * @param args the arguments to check
     * @return {@code true} if if at least one of the specified arguments is a marker, {@code false} otherwise
     */
    private static boolean containsMarkers(List<? extends AssignmentTestable> args)
    {
        return args.stream().anyMatch(Marker.Raw.class::isInstance);
    }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Cast the operand explicitly: SELECT -(int) col FROM t or -(double) col FROM t
Pin the result with CAST: SELECT CAST(-col AS double) FROM t
Use the expression where a typed receiver exists (e.g. compare to a typed literal)

Example fix

// before
SELECT -amount FROM orders; // amount is decimal, ambiguous
// after
datastax session.execute("SELECT -(double)amount FROM orders");

Defensive patterns

Strategy: validation

Validate before calling

function checkNegation(colType) { if (['decimal','varint','float'].includes(colType)) console.warn('negation ambiguous: cast explicitly, e.g. -(double)col'); }

Prevention

Never write bare -col on non-int columns; cast first
Pin expression types with CAST when column types can coerce multiple ways

When it happens

Trigger: A CQL query like SELECT -some_varint_or_decimal_col FROM t where the operand type is compatible with more than one negation signature and the surrounding context gives no receiver type.

Common situations: Negating decimal/varint/float columns where numeric literals or comparisons nearby don't pin a type; users writing -col in a SELECT list with no other typing context.

Understand the failure class

Background: "must be a positive integer", "cannot be empty", "invalid argument": how invalid-argument errors work across open-source libraries — this error's family across 33 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/3e93f7828b631d7b. Report an issue: GitHub.