# Release of Daml DAML_VERSION

## What’s New

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### Minor Script warning
As part of the ongoing efforts to improve Scripts and the testing story around them, we've added a small warning for a test case that non-obviously doesn't run.
Consider the following test:
```hs
myTest = script do
    ...
    error "Got here, and shouldn't have"
```
This test will not run, as it is implicitly polymorphic. Take a look at the type of [`error`](https://docs.daml.com/daml/stdlib/Prelude.html#function-ghc-err-error-7998), it returns `a`, and as such, so does `myTest`. We cannot "run" this without making `a` a concrete type, so this cannot be run.
We provide a warning in this case so a user may rectify this issue either by providing an explicit type signature, or by bounding the value of `a` in the call to `script`, via `script @()`.

### Restricted name warnings
Attempting to use the names `this`, `self` or `arg` in template, interface or exception fields will often result in confusing errors, mismatches with the underlying desugared code.  
We now throw an error (or warning) early in those cases on the field name itself to make this more clear.

*Note: Exception as well as templates without any choices did not previously throw errors for both `self` and `arg`. While using these names is discouraged, we only throw a warning here to avoid a breaking change. We may promote this to an error in future.*

### Dynamic Exercise
As part of extending the language to support evolving template definitions, we've added a new function `dynamicExercise : HasDynamicExercise t c r => ContractId t -> c -> Update r`, only available when targetting Daml LF version `1.dev`. Currently, it operates just like `exercise`, but at a later stage it will instead use the most recent definition of template `t` choice `c` vetter by all stakeholders.

### `daml script --ide-ledger`
In an effort to unify some of our internal and external tools, we now support the `--ide-ledger` option in `daml script`, allowing a user to directly invoke scripts within a `dar` file on their local machine, without a separate ledger running. Note the difference here with `daml test` being that `daml script` will not attempt to recompile or read the source code directly. This option cannot be used with `--ledger-host`, `--participant-config` or `--json-api`.