Type of string literal concatenated with non-immutable char array

[Per Nordlöw]

On Monday, 1 February 2021 at 10:27:29 UTC, Jacob Carlborg wrote:
>> Why isn't
>>
>>     "Name " ~ name ~ " could not be found"
>>
>> implicitly convertible to `string`?
>
> Because if you have arrays of reference types, it's possible to 
> change an element of the mutable array, which will affect the 
> immutable array, those breaking the immutability. Example:

I still don't understand why that restriction applies to arrays 
of values types (such as `char`). Having this limitation makes my 
code example more bloated or less efficient memorywise; I either 
have to define two separate ctors or force an .idup at the site 
of the exception construction.