---
title: SubjectInferenceError
framework: evaluations
role: symbol
role_heading: Enumeration
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, visionOS 27.0+, watchOS 27.0+]
path: evaluations/subjectinferenceerror
---

# SubjectInferenceError

A typed reason why subject(from:) failed to produce a subject for a sample.

## Declaration

```swift
enum SubjectInferenceError
```

## Overview

Overview Recorded in the detailed DataFrame’s SubjectInferenceError column for any row whose subject could not be produced. Distinct from EvaluatorError so each failure mode can grow its own cases independently — a subject-inference failure has no notion of an evaluator.

## Topics

### Enumeration Cases

- [SubjectInferenceError.failed(reason:)](evaluations/subjectinferenceerror/failed(reason:).md)

## Relationships

### Conforms To

- [Decodable](swift/decodable.md)
- [Encodable](swift/encodable.md)
- [Equatable](swift/equatable.md)
- [Error](swift/error.md)
- [Hashable](swift/hashable.md)
- [LocalizedError](foundation/localizederror.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Errors

- [EvaluationError](evaluations/evaluationerror.md)
- [EvaluatorError](evaluations/evaluatorerror.md)
- [EvaluationResultsError](evaluations/evaluationresultserror.md)