On Tuesday, 28 December 2021 at 07:54:56 UTC, frame wrote:
On Tuesday, 28 December 2021 at 06:38:03 UTC, Tejas wrote:
The workaround is okay, but I think we should file a bug
report for this.
This is very ~~stupid~~ undesirable behaviour
I agree. I'll just wait if somebody can explain why this isn't
a bug or wanted behaviour or a known issue.
[The spec
says](https://dlang.org/spec/hash-map.html#construction_assignment_entries):
```
2. If the assigned value type is equivalent with the AA element
type:
1. If the indexing key does not yet exist in AA, a new AA
entry will be allocated, and it will be initialized with the
assigned value.
2. If the indexing key already exists in the AA, the setting
runs normal assignment.
```
Thus, when the value type is constructable but not assignable:
```d
struct S
{
const(int) a;
}
void test(S[string] aa, string key, int value)
{
// Should be a compile-time error, because it might reassign:
test[key] = S(value);
// Should be accepted, because they can be proven at compile
time to never reassign:
test.require("a", S(value));
test.update("a", () => S(value), (ref const(S)) => { });
}
```
`require` and `update` can be fixed rather easily in `object.d`;
I have submitted [issue
22633](https://issues.dlang.org/show_bug.cgi?id=22633) with
sample code.
