rustdoc: Replace `FakeDefId` with new `ItemId` type #86644

Stupremee · 2021-06-26T11:58:04Z

Follow up from #84707

@Manishearth suggested that there should be a new ItemId type that can distinguish between auto traits, normal ids, and blanket impls instead of using FakeDefIds.

This type is introduced by this PR.

There are still some FIXMEs left, because I was unsure what the best solution for them would be.

Especially the naming in general now is a bit weird right now and needs to be cleaned up. Now there are no "fake" ids so the is_fake method on Item does not really make sense and maybe the methods on ItemId should be renamed too?

Also, we need to represent the new item ids in the JSON backend somehow.

rust-highfive · 2021-06-26T11:58:07Z

r? @GuillaumeGomez

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src/librustdoc/clean/types.rs

src/librustdoc/json/conversions.rs

jyn514 · 2021-06-26T14:19:09Z

r? @jyn514

src/librustdoc/clean/types.rs

src/librustdoc/formats/cache.rs

src/librustdoc/passes/collect_intra_doc_links.rs

Manishearth

I like this a lot, thanks for doing this! I don't really have any feedback that hasn't been brought up already aside from the boxing thing

src/librustdoc/clean/types.rs

jyn514 · 2021-07-02T08:50:46Z

r? @CraftSpider - this looks great other than the JSON IDs. I'm fine with reverting the "Box ImplId" commit.

Stupremee · 2021-07-03T13:31:10Z

This should be ready now!

r? @CraftSpider

src/librustdoc/json/conversions.rs

jyn514 · 2021-07-03T19:39:52Z

src/librustdoc/clean/blanket_impl.rs

@@ -96,7 +96,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                    name: None,
                    attrs: Default::default(),
                    visibility: Inherited,
-                    def_id: ItemId::Blanket { trait_: trait_def_id, for_: item_def_id },
+                    def_id: ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id },


Sorry, I was unclear: you don't need for_ at all now, you can reconstruct it from the impl_id alone with tcx.impl_trait_ref(impl_def_id).unwrap().self_ty().

Suggested change

def_id: ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id },

def_id: ItemId::Blanket { impl_def_id, },

Yes, I do need it, because apparently, only the implementation id is not enough to be unique (?????????).
When I only had the impl_id, I got a panic when documenting std that assert_eq on these two failed:

left: `Item { id: Id("b:0:2454"), crate_id: 0, name: None, span: Some(Span { filename: "library/core/src/borrow.rs", begin: (208, 0), end: (213, 1) }), visibility: Default, docs: None, links: {}, attrs: [], deprecation: None, inner: Impl(Impl { is_unsafe: false, generics: Generics { params: [GenericParamDef { name: "T", kind: Type { bounds: [], default: None } }], where_predicates: [BoundPredicate { ty: Generic("T"), bounds: [TraitBound { trait_: ResolvedPath { name: "Sized", id: Id("0:2854"), args: Some(AngleBracketed { args: [], bindings: [] }), param_names: [] }, generic_params: [], modifier: Maybe }] }] }, provided_trait_methods: [], trait_: Some(ResolvedPath { name: "Borrow", id: Id("0:2448"), args: Some(AngleBracketed { args: [Type(Generic("T"))], bindings: [] }), param_names: [] }), for_: ResolvedPath { name: "Wrapping", id: Id("0:24138"), args: Some(AngleBracketed { args: [Type(Generic("T"))], bindings: [] }), param_names: [] }, items: [Id("0:2456")], negative: false, synthetic: false, blanket_impl: Some(Generic("T")) }) }`, right: `Item { id: Id("b:0:2454"), crate_id: 0, name: None, span: Some(Span { filename: "library/core/src/borrow.rs", begin: (208, 0), end: (213, 1) }), visibility: Default, docs: None, links: {}, attrs: [], deprecation: None, inner: Impl(Impl { is_unsafe: false, generics: Generics { params: [GenericParamDef { name: "T", kind: Type { bounds: [], default: None } }], where_predicates: [BoundPredicate { ty: Generic("T"), bounds: [TraitBound { trait_: ResolvedPath { name: "Sized", id: Id("0:2854"), args: Some(AngleBracketed { args: [], bindings: [] }), param_names: [] }, generic_params: [], modifier: Maybe }] }] }, provided_trait_methods: [], trait_: Some(ResolvedPath { name: "Borrow", id: Id("0:2448"), args: Some(AngleBracketed { args: [Type(Generic("T"))], bindings: [] }), param_names: [] }), for_: ResolvedPath { name: "ParseFloatError", id: Id("0:23084"), args: Some(AngleBracketed { args: [], bindings: [] }), param_names: [] }, items: [Id("0:2456")], negative: false, synthetic: false, blanket_impl: Some(Generic("T")) }) }`', src/librustdoc/json/mod.rs:179:17

... @CraftSpider why are those separate? I would only expect there to be one item per blanket impl, generating a separate item for every type it could apply to seems both inefficient and not particularly useful.

I have no clue, I'd expect the same. I'll look into the code tomorrow.
First guess: the equivalent of HTML's 'implements' showing blankets that apply to that type

Should we wait with this PR until you found a solution? We can also merge this now and make a follow up PR.

Hmm, yeah this seems fine in the meantime. r=me once you fix the conflict.

Agree with Josh, this isn't a blocking concern.

Alright. @CraftSpider will you open the follow-up PR with the fix for not emitting duplicate blanket implementations and the fixed ItemId?

bors · 2021-07-05T07:48:51Z

☔ The latest upstream changes (presumably #86282) made this pull request unmergeable. Please resolve the merge conflicts.

…s size" This reverts commit 41a345d4c46dad1a98c9993bc78513415994e8ba.

Stupremee · 2021-07-05T17:53:19Z

r? @jyn514

jyn514 · 2021-07-05T18:30:20Z

@bors r+

bors · 2021-07-05T18:30:22Z

📌 Commit a89912c has been approved by jyn514

bors · 2021-07-06T04:13:56Z

⌛ Testing commit a89912c with merge 9a27044...

bors · 2021-07-06T06:54:50Z

☀️ Test successful - checks-actions
Approved by: jyn514
Pushing 9a27044 to master...

rust-highfive assigned GuillaumeGomez Jun 26, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 26, 2021

Stupremee added the T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. label Jun 26, 2021

jyn514 reviewed Jun 26, 2021

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rust-highfive assigned jyn514 and unassigned GuillaumeGomez Jun 26, 2021