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kotlinlang

Timer1.kt

Getting an error on the `tag` within my `start` method saying:
&gt;Required:
&gt;Tag&lt;T#1 (type parameter of com.revl.metrics.Timer1.start)&gt;
&gt;Found:
&gt;Tag&lt;T#2 (type parameter of com.revl.metrics.Timer1)&gt;

You have two different `T`'s, either that's a mistake or you should at least give them different names.

If you're trying to reuse the same `T` generic type argument defined in your class, remove the second definition of `T` in the function:
```
fun start(): NeedsTag1&lt;T, StartedTimer&gt; {
```
Because what you have right now, and I think you have not noticed, is:
```
class Timer1&lt;T : TagValue&gt;(
//...
fun &lt;U : TagValue&gt; start(): NeedsTag1&lt;U, StartedTimer&gt; {
```
where `T` and `U` are not the same types. Calling it with the same name won't do what you expect here.
I assume, by the nature of the error, that NeedsTag1 needs a tag of the same type passed as the first generic type argument (`U` in my example), so if this is true, you need to pass a `Tag&lt;U&gt;` to the constructor. However, your `tag` value of the class is of type `Tag&lt;T&gt;`!