[Dlang-internal] UDA segfaults compiler

[Elmar]

On Sunday, 18 July 2021 at 17:37:52 UTC, Basile B. wrote:
> On Saturday, 17 July 2021 at 16:33:54 UTC, Elmar wrote:
>> Hello D people,
>>
>> I found a segmentation fault which I can reproduce with `dmd` 
>> and `ldc2`.
>>
>> The attack code is simple:
>>
>> ```
>> alias getOne = @(0) function int () => 1;
>> ```
>>
>> It works without the UDA but segfaults with it. I found it 
>> because I wanted to have user-defined attributes to the return 
>> values of functions. I can't put the UDA after `function` so I 
>> put it before.
>>
>> I believe, this is a forgotton corner case or something 
>> because the compiler tells me, UDAs are not allowed in alias 
>> definitions.
>
> This is an assertion failure in the parser, [reported 
> here](https://issues.dlang.org/show_bug.cgi?id=22127).
>
> The code you write should not compile because the 
> FunctionLiteral rule does not include the UserDefinedAttributes 
> one.

Thank you very much for clarification :-) ! I figured out UDAs 
are supposed to be attached to symbols only and because of 
compile-time staticness they can only be passed to a function via 
an alias-parameter but can't be passed to an op-function or 
constructor unfortunately. The deprecated dual-context makes it 
harder to pass them to methods and some other functions.

Thank you for adding the report!