Rollup merge of rust-lang#122771 - RalfJung:module-items, r=oli-obk

add some comments to hir::ModuleItems

I've definitely been bitten by this in the past, where I assumed `items()` would give me *all* the items.

compiler/rustc_incremental/src/persist/dirty_clean.rs

@@ -148,7 +148,7 @@ pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
 
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             dirty_clean_visitor.check_item(id.owner_id.def_id);
         }
 

compiler/rustc_middle/src/hir/map/mod.rs

@@ -166,12 +166,12 @@ impl<'hir> Map<'hir> {
 
     #[inline]
     pub fn items(self) -> impl Iterator<Item = ItemId> + 'hir {
-        self.tcx.hir_crate_items(()).items.iter().copied()
+        self.tcx.hir_crate_items(()).free_items.iter().copied()
     }
 
     #[inline]
     pub fn module_items(self, module: LocalModDefId) -> impl Iterator<Item = ItemId> + 'hir {
-        self.tcx.hir_module_items(module).items()
+        self.tcx.hir_module_items(module).free_items()
     }
 
     pub fn def_key(self, def_id: LocalDefId) -> DefKey {
@@ -418,7 +418,7 @@ impl<'hir> Map<'hir> {
         V: Visitor<'hir>,
     {
         let krate = self.tcx.hir_crate_items(());
-        walk_list!(visitor, visit_item, krate.items().map(|id| self.item(id)));
+        walk_list!(visitor, visit_item, krate.free_items().map(|id| self.item(id)));
         walk_list!(visitor, visit_trait_item, krate.trait_items().map(|id| self.trait_item(id)));
         walk_list!(visitor, visit_impl_item, krate.impl_items().map(|id| self.impl_item(id)));
         walk_list!(
@@ -436,7 +436,7 @@ impl<'hir> Map<'hir> {
         V: Visitor<'hir>,
     {
         let module = self.tcx.hir_module_items(module);
-        walk_list!(visitor, visit_item, module.items().map(|id| self.item(id)));
+        walk_list!(visitor, visit_item, module.free_items().map(|id| self.item(id)));
         walk_list!(visitor, visit_trait_item, module.trait_items().map(|id| self.trait_item(id)));
         walk_list!(visitor, visit_impl_item, module.impl_items().map(|id| self.impl_item(id)));
         walk_list!(
@@ -1197,7 +1197,7 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
     } = collector;
     return ModuleItems {
         submodules: submodules.into_boxed_slice(),
-        items: items.into_boxed_slice(),
+        free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
@@ -1226,7 +1226,7 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
 
     return ModuleItems {
         submodules: submodules.into_boxed_slice(),
-        items: items.into_boxed_slice(),
+        free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),

compiler/rustc_middle/src/hir/mod.rs

@@ -22,22 +22,30 @@ use rustc_span::{ErrorGuaranteed, ExpnId};
 #[derive(Debug, HashStable, Encodable, Decodable)]
 pub struct ModuleItems {
     submodules: Box<[OwnerId]>,
-    items: Box<[ItemId]>,
+    free_items: Box<[ItemId]>,
     trait_items: Box<[TraitItemId]>,
     impl_items: Box<[ImplItemId]>,
     foreign_items: Box<[ForeignItemId]>,
     body_owners: Box<[LocalDefId]>,
 }
 
 impl ModuleItems {
-    pub fn items(&self) -> impl Iterator<Item = ItemId> + '_ {
-        self.items.iter().copied()
+    /// Returns all non-associated locally defined items in all modules.
+    ///
+    /// Note that this does *not* include associated items of `impl` blocks! It also does not
+    /// include foreign items. If you want to e.g. get all functions, use `definitions()` below.
+    ///
+    /// However, this does include the `impl` blocks themselves.
+    pub fn free_items(&self) -> impl Iterator<Item = ItemId> + '_ {
+        self.free_items.iter().copied()
     }
 
     pub fn trait_items(&self) -> impl Iterator<Item = TraitItemId> + '_ {
         self.trait_items.iter().copied()
     }
 
+    /// Returns all items that are associated with some `impl` block (both inherent and trait impl
+    /// blocks).
     pub fn impl_items(&self) -> impl Iterator<Item = ImplItemId> + '_ {
         self.impl_items.iter().copied()
     }
@@ -47,7 +55,7 @@ impl ModuleItems {
     }
 
     pub fn owners(&self) -> impl Iterator<Item = OwnerId> + '_ {
-        self.items
+        self.free_items
             .iter()
             .map(|id| id.owner_id)
             .chain(self.trait_items.iter().map(|id| id.owner_id))
@@ -63,7 +71,7 @@ impl ModuleItems {
         &self,
         f: impl Fn(ItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
     ) -> Result<(), ErrorGuaranteed> {
-        try_par_for_each_in(&self.items[..], |&id| f(id))
+        try_par_for_each_in(&self.free_items[..], |&id| f(id))
     }
 
     pub fn par_trait_items(

compiler/rustc_monomorphize/src/collector.rs

@@ -307,7 +307,7 @@ fn collect_roots(tcx: TyCtxt<'_>, mode: MonoItemCollectionMode) -> Vec<MonoItem<
 
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             collector.process_item(id);
         }
 

compiler/rustc_passes/src/dead.rs

@@ -831,7 +831,7 @@ fn create_and_seed_worklist(
         .collect::<Vec<_>>();
 
     let crate_items = tcx.hir_crate_items(());
-    for id in crate_items.items() {
+    for id in crate_items.free_items() {
         check_item(tcx, &mut worklist, &mut struct_constructors, &mut unsolved_impl_item, id);
     }
 
@@ -1084,7 +1084,7 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
 
     let module_items = tcx.hir_module_items(module);
 
-    for item in module_items.items() {
+    for item in module_items.free_items() {
         let def_kind = tcx.def_kind(item.owner_id);
 
         let mut dead_codes = Vec::new();

compiler/rustc_passes/src/reachable.rs

@@ -437,7 +437,7 @@ fn reachable_set(tcx: TyCtxt<'_>, (): ()) -> LocalDefIdSet {
         // trait is a lang item.
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             check_item(tcx, id, &mut reachable_context.worklist, effective_visibilities);
         }
 

compiler/rustc_privacy/src/lib.rs

@@ -1696,7 +1696,7 @@ fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
         }
     }
 
-    for id in module.items() {
+    for id in module.free_items() {
         if let ItemKind::Impl(i) = tcx.hir().item(id).kind {
             if let Some(item) = i.of_trait {
                 let trait_ref = tcx.impl_trait_ref(id.owner_id.def_id).unwrap();

compiler/rustc_symbol_mangling/src/test.rs

@@ -25,7 +25,7 @@ pub fn report_symbol_names(tcx: TyCtxt<'_>) {
         let mut symbol_names = SymbolNamesTest { tcx };
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             symbol_names.process_attrs(id.owner_id.def_id);
         }
 

tests/run-make-fulldeps/obtain-borrowck/driver.rs

@@ -68,7 +68,7 @@ impl rustc_driver::Callbacks for CompilerCalls {
             let mut bodies = Vec::new();
 
             let crate_items = tcx.hir_crate_items(());
-            for id in crate_items.items() {
+            for id in crate_items.free_items() {
                 if matches!(tcx.def_kind(id.owner_id), DefKind::Fn) {
                     bodies.push(id.owner_id);
                 }