# QueryConstructionError

- **Package:** libtmux-swift
- **Language:** Swift
- **Kind:** enum
- **Source:** https://github.com/libtmux/libtmux-swift/blob/f02a4668570e1cc5198c941413750e021f42c214/Sources/LibTmux/FilterExpr.swift#L28
- **Page:** https://libtmux.org/reference/swift/queryconstructionerror/

Why a filter could not be built.

## Members

- `!=(_:_:)` (function) — Returns a Boolean value indicating whether two values are not equal.
- `localizedDescription` (property) — Retrieve the localized description for this error.
- `unknownField` (constant) — The key path does not name a filterable field of this model.
- `invalidOperation(_:)` (constant) — The field and operator could not form a safe expression.