Nested unary negation causes a declared bind parameter to be reported as undeclared

repro_2_nested_unary_bind_validation.py

Description

A bind parameter that is syntactically present in nested unary-negation expressions is rejected as undeclared. The server reports error 1552 even though @x appears in the query and x is supplied in bindVars.

This differs from the related incorrect-result issue: this case rejects a valid query instead of returning a wrong successful result.

Environment

• ArangoDB: 3.12.9-4
• Deployment: official Docker image, single server
• OS hosting Docker: Windows / Docker Desktop / WSL2
• API: HTTP cursor API

Steps to reproduce

Query:

RETURN -(-(-@x))

Bind variables:

{"x": 1}

Expected result

[-1]

Actual result

ERR 1552: bind parameter 'x' was not declared in the query

Why this appears incorrect

@x is explicitly present and supplied. Equivalent expressions using a LET variable or subtraction do not lose bind-parameter recognition. This may share an AST/optimizer root cause with unary bind expressions evaluating to zero, but the externally visible behavior and error path are separate.