Unused import tool

[RazvanN]

On Wednesday, 16 August 2023 at 05:26:11 UTC, Basile B. wrote:

> You can handle nested import declarations without the scope. 
> The trick would be to use a single visitor and a 2D import 
> list, i.e`ImportInfo[][] imports;`. The first dim matches to a 
> scope, so when you enter a scope (BlockStmt, AggrDecl, etc) you 
> push the local imports, and when you leave the scope, you check 
> and pop. Styx 
> [Example](https://gitlab.com/styx-lang/styx/-/blob/master/src/styx/lint.sx?ref_type=heads#L247), (which has same semantics as D about out-of-order decls).
>

Indeed, there are solutions to this problem. Another one is to 
treat scope as dscanner does now (the scope is just an integer 
which is incremented and decremented whenever a scope is 
entered/left), however, I was hoping to leverage most of the 
existing logic in the compiler.

>
> This is why I think that such a tool should be integrated to 
> the compiler.
>

I am now looking for a way to integrate this in the compiler to 
better understand what the compiler would need to expose in order 
to properly implement this. I thought it would be easy, 
unfortunately, when dmd does symbol resolution, the search 
methods work on a list of imported scopes (e.g. modules or 
mixins) and currently there is no way to tie the imported scope 
to a specific import declaration/statement. DMD's code could be 
altered to store the import instead of the module, however, 
Walter has made it clear that such linting behavior will not be 
accepted in dmd.

RazvanN