const on AliasSeq ignored

[dlangBugzillaToGithub]

Yuxuan Shui (@yshui) reported this on 2019-04-08T23:09:51Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=19794

CC List

• ag0aep6g
• basile-z
• Victor Porton

Description

const(AliasSeq!(int, int)) a;

pragma(msg, typeof(a));  // <- (int, int)


The compiler should probably at least generate a warning for this case.

[dlangBugzillaToGithub]

ag0aep6g commented on 2019-04-08T23:17:37Z

Noteworthy:

const AliasSeq!(int, int) b;
pragma(msg, typeof(b)); /* (const(int), const(int)) */

[dlangBugzillaToGithub]

simen.kjaras commented on 2019-05-05T14:39:29Z

*** Issue 19845 has been marked as a duplicate of this issue. ***

[dlangBugzillaToGithub]

b2.temp commented on 2023-12-16T21:06:20Z

Not and ER, that is well a bug, according to https://dlang.org/spec/const3.html#const_type

> [...]. Each applies transitively to all subtypes.

The problem is that the DMD class `TypeTuple` (in mtype.d) does not override `.constOf`, `immutableOf()`, etc.

Tagging as accept-invalid given that

```d
alias AliasSeq(T...) = T;

const(AliasSeq!(int, int)) a;

void main()
{
    a[0] = 1;
}    
```

should be reject just like when `const` is variable storage class.