daml/sdk/UNRELEASED.md

# Release of Daml DAML_VERSION
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## Bugfixes

## What’s New

# Release of Daml 2.8.1

## Bugfixes

## What’s New

# Release of Daml 2.9.0

## Bugfixes

## What’s New

# Release of Daml 3.0.0

## Bugfixes

## What’s New

* The type class `HasField` (methods `getField` and `setField`) has been split
  in two: `GetField` and `SetField`, each one with the correspondingly named
  method. `HasField` is now defined as a type synonym for the conjunction of
  `GetField` and `SetField`. This means that functions with `HasField`
  constraints will continue to work without any changes.

  No action should be necessary for migrating the compiler-generated instances
  for record types. For user-defined instances of the `HasField` class,
  migration is a matter of replacing one instance declaration with two, for
  example,

  ```daml
  instance HasField "field_name" RecType FieldType where
    getField = <getFieldImpl>
    setField = <setFieldImpl>
  ```

  would have to be rewritten as

  ```daml
  instance GetField "field_name" RecType FieldType where
    getField = <getFieldImpl>

  instance SetField "field_name" RecType FieldType where
    setField = <setFieldImpl>
  ```

* User-defined instances of the class `GetField` enable the use of dot-syntax
  for field access, i.e. `rec.field`

* User-defined instances of the class `SetField` enable the use of with-syntax
  for field update, i.e. `rec with field = newValue`

* Removed support for "template-let" syntax, previously deprecated in Daml 2.8.0.
  See [Template-local Definitions (Deprecated)](https://docs.daml.com/daml/reference/templates.html#template-local-definitions-deprecated)
  for migration guidance.