Rollup merge of #148623 - trimmed-paths, r=davidtwco

Ignore `#[doc(hidden)]` items when computing trimmed paths for printing

The `trimmed_def_paths` query examines all items in the current crate, and all pub items in immediate-dependency crates (including the standard library), to see which item names are unique and can therefore be printed unambiguously as a bare name without a module path.

Currently that query has no special handling for `#[doc(hidden)]` items, which has two consequences:
- Hidden names can be considered unique, and will therefore be printed without a path, making it hard to find where that name is defined (since it normally isn't listed in documentation).
- Hidden names can conflict with visible names that would otherwise be considered unique, causing diagnostics to mysteriously become more verbose based on internal details of other crates.

This PR therefore makes the `trimmed_def_paths` query ignore external-crate items that are `#[doc(hidden)]`, along with their descendants.

As a result, hidden item names are never considered unique for trimming, and no longer interfere with visible item names being considered unique.

---
- Fixes #148387.

Author: JonathanBrouwer

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -3421,6 +3421,13 @@ fn for_each_def(tcx: TyCtxt<'_>, mut collect_fn: impl for<'b> FnMut(&'b Ident, N
                 def::Res::Def(DefKind::AssocTy, _) => {}
                 def::Res::Def(DefKind::TyAlias, _) => {}
                 def::Res::Def(defkind, def_id) => {
+                    // Ignore external `#[doc(hidden)]` items and their descendants.
+                    // They shouldn't prevent other items from being considered
+                    // unique, and should be printed with a full path if necessary.
+                    if tcx.is_doc_hidden(def_id) {
+                        continue;
+                    }
+
                     if let Some(ns) = defkind.ns() {
                         collect_fn(&child.ident, ns, def_id);
                     }

tests/mir-opt/async_closure_fake_read_for_by_move.foo-{closure#0}-{closure#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `foo::{closure#0}::{closure#0}` after built
 
-fn foo::{closure#0}::{closure#0}(_1: {async closure body@$DIR/async_closure_fake_read_for_by_move.rs:12:27: 15:6}, _2: ResumeTy) -> ()
+fn foo::{closure#0}::{closure#0}(_1: {async closure body@$DIR/async_closure_fake_read_for_by_move.rs:12:27: 15:6}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/async_closure_fake_read_for_by_move.foo-{closure#0}-{synthetic#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `foo::{closure#0}::{synthetic#0}` after built
 
-fn foo::{closure#0}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_fake_read_for_by_move.rs:12:27: 15:6}, _2: ResumeTy) -> ()
+fn foo::{closure#0}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_fake_read_for_by_move.rs:12:27: 15:6}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/async_closure_shims.main-{closure#0}-{closure#0}-{closure#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `main::{closure#0}::{closure#0}::{closure#0}` after built
 
-fn main::{closure#0}::{closure#0}::{closure#0}(_1: {async closure body@$DIR/async_closure_shims.rs:53:53: 56:10}, _2: ResumeTy) -> ()
+fn main::{closure#0}::{closure#0}::{closure#0}(_1: {async closure body@$DIR/async_closure_shims.rs:53:53: 56:10}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/async_closure_shims.main-{closure#0}-{closure#0}-{synthetic#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `main::{closure#0}::{closure#0}::{synthetic#0}` after built
 
-fn main::{closure#0}::{closure#0}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_shims.rs:53:53: 56:10}, _2: ResumeTy) -> ()
+fn main::{closure#0}::{closure#0}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_shims.rs:53:53: 56:10}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/async_closure_shims.main-{closure#0}-{closure#1}-{closure#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `main::{closure#0}::{closure#1}::{closure#0}` after built
 
-fn main::{closure#0}::{closure#1}::{closure#0}(_1: {async closure body@$DIR/async_closure_shims.rs:62:48: 65:10}, _2: ResumeTy) -> ()
+fn main::{closure#0}::{closure#1}::{closure#0}(_1: {async closure body@$DIR/async_closure_shims.rs:62:48: 65:10}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/async_closure_shims.main-{closure#0}-{closure#1}-{synthetic#0}.built.after.mir

@@ -1,6 +1,6 @@
 // MIR for `main::{closure#0}::{closure#1}::{synthetic#0}` after built
 
-fn main::{closure#0}::{closure#1}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_shims.rs:62:48: 65:10}, _2: ResumeTy) -> ()
+fn main::{closure#0}::{closure#1}::{synthetic#0}(_1: {async closure body@$DIR/async_closure_shims.rs:62:48: 65:10}, _2: std::future::ResumeTy) -> ()
 yields ()
  {
     debug _task_context => _2;

tests/mir-opt/box_expr.rs

@@ -8,7 +8,7 @@ fn main() {
     // CHECK-LABEL: fn main(
     // CHECK:   [[ptr:_.*]] = move {{_.*}} as *const S (Transmute);
     // CHECK:   [[nonnull:_.*]] = NonNull::<S> { pointer: move [[ptr]] };
-    // CHECK:   [[unique:_.*]] = Unique::<S> { pointer: move [[nonnull]], _marker: const PhantomData::<S> };
+    // CHECK:   [[unique:_.*]] = std::ptr::Unique::<S> { pointer: move [[nonnull]], _marker: const PhantomData::<S> };
     // CHECK:   [[box:_.*]] = Box::<S>(move [[unique]], const std::alloc::Global);
     // CHECK:   [[ptr:_.*]] = copy (([[box]].0: std::ptr::Unique<S>).0: std::ptr::NonNull<S>) as *const S (Transmute);
     // CHECK:   (*[[ptr]]) = S::new() -> [return: [[ret:bb.*]], unwind: [[unwind:bb.*]]];

tests/mir-opt/building/issue_101867.main.built.after.mir

@@ -32,7 +32,7 @@ fn main() -> () {
     bb1: {
         StorageLive(_3);
         StorageLive(_4);
-        _4 = begin_panic::<&str>(const "explicit panic") -> bb8;
+        _4 = std::rt::begin_panic::<&str>(const "explicit panic") -> bb8;
     }
 
     bb2: {

tests/mir-opt/const_prop/boxes.main.GVN.panic-abort.diff

@@ -29,10 +29,10 @@
           StorageLive(_5);
 -         _6 = move _4 as *const i32 (Transmute);
 -         _7 = NonNull::<i32> { pointer: move _6 };
--         _8 = Unique::<i32> { pointer: move _7, _marker: const PhantomData::<i32> };
+-         _8 = std::ptr::Unique::<i32> { pointer: move _7, _marker: const PhantomData::<i32> };
 +         _6 = copy _4 as *const i32 (PtrToPtr);
 +         _7 = NonNull::<i32> { pointer: copy _6 };
-+         _8 = Unique::<i32> { pointer: copy _7, _marker: const PhantomData::<i32> };
++         _8 = std::ptr::Unique::<i32> { pointer: copy _7, _marker: const PhantomData::<i32> };
           _5 = Box::<i32>(move _8, const std::alloc::Global);
 -         _9 = copy ((_5.0: std::ptr::Unique<i32>).0: std::ptr::NonNull<i32>) as *const i32 (Transmute);
 -         (*_9) = const 42_i32;