[wip] try to process impl blocks in collect pass

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

this is so curseeeeeeed

currently failing:
- rustdoc/doc-cfg-simplification.rs
- rustdoc/intra-doc-crate/self.rs

src/librustdoc/core.rs

@@ -467,6 +467,8 @@ crate fn run_global_ctxt(
         rustc_errors::FatalError.raise();
     }
 
+    ctxt.cache.populate_impls(&krate);
+
     (krate, ctxt.render_options, ctxt.cache)
 }
 

src/librustdoc/formats/cache.rs

@@ -179,9 +179,17 @@ impl Cache {
                 }
             }
         }
+        // god what a mess
+        *krate.external_traits.borrow_mut() = mem::take(&mut cx.cache.traits);
 
         krate
     }
+
+    /// `external_trats` / `cache.traits` is modified in various passes.
+    /// Run this separate from the main `populate` call, since `impls` isn't used until later in the HTML formatter.
+    crate fn populate_impls(&mut self, krate: &clean::Crate) {
+        self.traits = krate.external_traits.take();
+    }
 }
 
 impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
@@ -462,7 +470,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                     }
                 }
             }
-            let impl_item = Impl { impl_item: item.clone() };
+            let impl_item = Impl { impl_item: item };
             if impl_item.trait_did().map_or(true, |d| self.cache.traits.contains_key(&d)) {
                 for did in dids {
                     self.cache.impls.entry(did).or_insert_with(Vec::new).push(impl_item.clone());
@@ -472,7 +480,14 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                 self.cache.orphan_trait_impls.push((trait_did, dids, impl_item.clone()));
             }
             // TODO: stripping this from `Module` seems ... not great
-            Some(impl_item.impl_item)
+            // None
+            let item = impl_item.impl_item;
+            if item.def_id.is_local() {
+                debug!("propagating impl {:?}", item);
+                Some(item)
+            } else {
+                None
+            }
         } else {
             Some(item)
         };

src/librustdoc/formats/mod.rs

@@ -25,6 +25,7 @@ crate enum RenderMode {
 
 /// Metadata about implementations for a type or trait.
 #[derive(Clone, Debug)]
+// TODO: this should not exist
 crate struct Impl {
     crate impl_item: clean::Item,
 }

src/librustdoc/visit.rs

@@ -56,11 +56,6 @@ crate trait DocVisitor: Sized {
 
     fn visit_mod(&mut self, m: &Module) {
         m.items.iter().for_each(|i| self.visit_item(i));
-        // for i in self.cache.impls {
-        //     if m.def_id() == find_nearest_parent_module(self.tcx, i.def_id) {
-        //         self.visit_item(i);
-        //     }
-        // }
     }
 
     fn visit_crate(&mut self, c: &Crate) {

src/test/rustdoc-ui/assoc-item-not-in-scope.stderr

@@ -1,20 +1,3 @@
-warning: documentation for `f` links to item `S::fmt` which will not have documentation generated
-  --> $DIR/assoc-item-not-in-scope.rs:12:18
-   |
-LL |     /// Link to [`S::fmt`]
-   |                  ^^^^^^^^ this item is will not be documented
-   |
-   = note: `#[warn(rustdoc::private_intra_doc_links)]` on by default
-   = note: `S::fmt` may be in a private module with all re-exports marked as `#[doc(no_inline)]`
-
-warning: documentation for `f` links to item `S::fmt` which will not have documentation generated
-  --> $DIR/assoc-item-not-in-scope.rs:20:18
-   |
-LL |     /// Link to [`S::fmt`]
-   |                  ^^^^^^^^ this item is will not be documented
-   |
-   = note: `S::fmt` may be in a private module with all re-exports marked as `#[doc(no_inline)]`
-
 error: unresolved link to `S::fmt`
   --> $DIR/assoc-item-not-in-scope.rs:4:15
    |
@@ -27,5 +10,5 @@ note: the lint level is defined here
 LL | #![deny(rustdoc::broken_intra_doc_links)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 2 warnings emitted
+error: aborting due to previous error
 

src/tools/compiletest/src/runtest.rs

@@ -1490,6 +1490,7 @@ impl<'test> TestCx<'test> {
             .arg(out_dir)
             .arg("--deny")
             .arg("warnings")
+            .arg("-Arustdoc::private-intra-doc-links")
             .arg(&self.testpaths.file)
             .args(&self.props.compile_flags);