Fix link generation for local primitive types in rustdoc JSON output

[GuillaumeGomez]

Fixes #104064.

As mentioned in the issue, I'm not super happy about this fix which is more a hack rather than a sound-proof solution. However I couldn't find a better way to fix it.

r? @aDotInTheVoid

[aDotInTheVoid]

Given that primitives are handled with the DisplayDefId machinery, we're not using ItemId::Primitive here. What does is it used for?

This PR should also remove the code path for ItemId::Primitive to clairify that its not used.

rust/src/librustdoc/json/conversions.rs

Lines 232 to 241 in c757267

	match item_id {
	ItemId::DefId(did) => Id(format!("{}", DisplayDefId(did, tcx, name))),
	ItemId::Blanket { for_, impl_id } => {
	Id(format!("b:{}-{}", DisplayDefId(impl_id, tcx, None), DisplayDefId(for_, tcx, name)))
	}
	ItemId::Auto { for_, trait_ } => {
	Id(format!("a:{}-{}", DisplayDefId(trait_, tcx, None), DisplayDefId(for_, tcx, name)))
	}
	ItemId::Primitive(ty, krate) => Id(format!("p:{}:{}", krate.as_u32(), ty.as_sym())),
	}

-      ItemId::Primitive(ty, krate) => Id(format!("p:{}:{}", krate.as_u32(), ty.as_sym())), 
+      ItemId::Primitive(_, _) => unreachable!(),

I've tested this localy, but github won't let me suggest changes for lines "to far" from the changed lines.

@rustbot author

[GuillaumeGomez]

ItemId::Primitive exists for the generation of the search index. But at this point, I think we could maybe remove it. To be investigated.

[GuillaumeGomez]

I removed the match pattern for the primitive type.

[aDotInTheVoid]

r=me when CI passes.

[GuillaumeGomez]

@bors r=aDotInTheVoid

[bors]

📌 Commit c9ebd73 has been approved by aDotInTheVoid

It is now in the queue for this repository.