check_fault -- effect that terminates a computation due to a failed
condition in a check statement

contract_fault -- effect that terminates a computation due to a failed
condition in a pre, post or check statement

fault -- effect that terminates a computation due to a runtime fault

invariant_fault -- effect that terminates a computation due to a failed
condition in a inv statement

post_fault -- effect that terminates a computation due to a failed runtime post
condition check

pre_fault -- effect that terminates a computation due to a failed runtime pre
condition check

variant_fault -- effect that terminates a computation due to a failed
condition in a var statement

create a String from this instance. Unless redefined, `a.as_string` will
create `"instance[T]"` where `T` is the dynamic type of `a`

check_fault with no argument returns check_fault.env, the currently installed
runtime check_fault handler.

cause a check fault with given msg argument, i.e., call check_fault.cause
msg, i.e., use the current check_fault effect to fail with the given message.

contract_fault with no argument returns contract_fault.env, the currently installed
runtime contract_fault handler.

dynamic_apply -- apply `f.call` to `Any.this`'s dynamic type and value

This can be used to perform operation on values depending on their dynamic
type.

Here is an example that takes a `Sequence Any` that may contain boxed values
of types `i32` and `f64`. We can now write a feature `get_f64` that extracts
these values converted to `f64` and build a function `sum` that sums them up
as follows:


NYI: IMPROVEMENT: #5892: If this is fixed, we could write

Get the dynamic type of this instance. For value instances `x`, this is
equal to `type_of x`, but for `x` with a `ref` type `x.dynamic_type` gives
the actual runtime type, while `type_of x` results in the static
compile-time type.

There is no dynamic type of a type instance since this would result in an
endless hierarchy of types. So for Type values, dynamic_type is redefined
to just return Type.type.

fault with no argument returns fault.env, the currently installed
runtime fault handler.

invariant_fault with no argument returns invariant_fault.env, the currently installed
runtime invariant_fault handler.

cause a inv fault with given msg argument, i.e., call invariant_fault.cause
msg, i.e., use the current invariant_fault effect to fail with the given message.

post_fault with no argument returns post_fault.env, the currently installed
runtime post_fault handler.

cause a postcondition fault with given msg argument, i.e., call post_fault.cause
msg, i.e., use the current post_fault effect to fail with the given message.

pre_fault with no argument returns pre_fault.env, the currently installed
runtime pre_fault handler.

cause a precondition fault with given msg argument, i.e., call pre_fault.cause
msg, i.e., use the current pre_fault effect to fail with the given message.

convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.

variant_fault with no argument returns variant_fault.env, the currently installed
runtime variant_fault handler.

cause a var fault with given msg argument, i.e., call variant_fault.cause
msg, i.e., use the current variant_fault effect to fail with the given message.

string representation of this type to be used for debugging.

result has the form "Type of '<name>'", but this might change in the future

There is no dynamic type of a type instance since this would result in an
endless hierarchy of types, so dynamic_type is redefined to just return
Type.type here.

Is this type assignable to a type parameter with constraint `T`?

The result of this is a compile-time constant that can be used to specialize
code for a particular type.


it is most useful in conjunction with preconditions or `if` statements as in


or

name of this type, including type parameters, e.g. 'option (list i32)'.

convenience prefix operator to create a string from a value.

This permits usage of `$` as a prefix operator in a similar way both
inside and outside of constant strings: $x and "$x" will produce the
same string.

NYI: Redefinition allows the type feature to be distinguished from its normal counterpart, see #3913

Get a type as a value.

This is a feature with the effect equivalent to Fuzion's `expr.type` call tail.
It is recommended to use `expr.type` and not `expr.type_value`.

`type_value` is here to show how this can be implemented and to illustrate the
difference to `dynamic_type`.