• Per =?UTF-8?B?Tm9yZGzDtnc=?= (8/8) May 05 2022 Why isn't `std.exception.assumeUnique` generically defined as
• Dennis (7/17) May 05 2022 The documentation says:
• Per =?UTF-8?B?Tm9yZGzDtnc=?= (7/9) May 05 2022 http://mir-algorithm.libmir.org/mir_string_map.html

Per =?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

Why isn't `std.exception.assumeUnique` generically defined as

```d
auto assumeUnique(T)(T x)  trusted {
	return cast(immutable)x;
}
```

instead of currently restricted to arrays at 
https://github.com/dlang/phobos/blob/master/std/exception.d#L905?

Dennis <dkorpel gmail.com> writes:

On Thursday, 5 May 2022 at 08:15:35 UTC, Per Nordlöw wrote:
 Why isn't `std.exception.assumeUnique` generically defined as

 ```d
 auto assumeUnique(T)(T x)  trusted {
 	return cast(immutable)x;
 }
 ```

That's not a correct use of ` trusted`

 instead of currently restricted to arrays at 
 https://github.com/dlang/phobos/blob/master/std/exception.d#L905?

The documentation says:

 Typically, `assumeUnique` is used to return arrays from 
 functions that have allocated and built them.

For a `struct` or `class`, you would typically use an `immutable` 
/ `pure` constructor, so there's less need for it. What non-array 
type do you want to use `assumeUnique` on and why don't you 
`cast(immutable)`?

Per =?UTF-8?B?Tm9yZGzDtnc=?= <per.nordlow gmail.com> writes:

On Thursday, 5 May 2022 at 12:32:07 UTC, Dennis wrote:
 What non-array type do you want to use `assumeUnique` on and 
 why don't you `cast(immutable)`?

http://mir-algorithm.libmir.org/mir_string_map.html

I _can_ use `cast(immutable)` but that needs to be qualified as 
 trusted.

`StringMap` is implemented using three pointers fields and one 
length field and is a hybrid between a normal array and an 
associative array.