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# unspecified

The proposed size with both dimensions left unspecified.

```
static let unspecified: ProposedViewSize
```

## Discussion

Both dimensions contain `nil` in this size proposal.
Subviews of a custom layout return their ideal size when you propose
this value using the [`dimensions(in:)`](/documentation/SwiftUI/LayoutSubview/dimensions(in:)) method.
A custom layout should also return its ideal size from the
[`sizeThatFits(proposal:subviews:cache:)`](/documentation/SwiftUI/Layout/sizeThatFits(proposal:subviews:cache:)) method for this
value.

---

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