On 2015-05-28 20:14:33 +0000, Gaetano Mendola wrote:
> src/backend/commands/explain.c:1692
> src/backend/commands/explain.c:1874
> src/backend/commands/explain.c:1986
> 
> there is the following assignment:
> 
>    ancestors = list_delete_first(ancestors);
> 
> but it has no effect at all being that a function parameter and not used
> anymore after the assignment itself.
So? It costs little to nothing, and it'll make it much less likely that
a stale version of 'ancestors' is used when the code is expanded.
Greetings,
Andres Freund