type parameter in operator overloading

Dart does not support adding types in operator overloading.

```dart
void operator |(T value);
```
It would be great if it is supported for function currying, piping using extension and operator overloading.

Review the Dart language specification areas covering operator overloading and generic type parameters; the issue names no files, tests, or entry points. Clarify the proposed syntax and semantics for generic operators, including the stated currying and piping use cases, and document whether the language change is feasible.

Written by the indexing model from the issue text.