Handle two different glob re-exports

Signed-off-by: longfangsong <longfangsong@icloud.com>

Author: longfangsong

src/librustdoc/doctree.rs

@@ -65,15 +65,18 @@ impl Module<'hir> {
 
     pub(crate) fn push_item(&mut self, ctx: &DocContext<'_>, new_item: Item<'hir>) {
         let new_item_ns = ctx.tcx.def_kind(new_item.hir_item.def_id).ns();
+        let mut to_remove = None;
         if !new_item.name().is_empty() && new_item_ns.is_some() {
-            if let Some(existing_item) = self.items.iter_mut().find(|item| {
-                item.name() == new_item.name()
-                    && ctx.tcx.def_kind(item.hir_item.def_id).ns() == new_item_ns
-            }) {
+            if let Some((index, existing_item)) =
+                self.items.iter_mut().enumerate().find(|(_, item)| {
+                    item.name() == new_item.name()
+                        && ctx.tcx.def_kind(item.hir_item.def_id).ns() == new_item_ns
+                })
+            {
                 match (existing_item.from_glob, new_item.from_glob) {
-                    (true, _) => {
-                        // `existing_item` is from glob, no matter whether `new_item` is from glob,
-                        // `new_item` should always shadow `existing_item`
+                    (true, false) => {
+                        // `existing_item` is from glob, `new_item` is not,
+                        // `new_item` should shadow `existing_item`
                         debug!("push_item: {:?} shadowed by {:?}", existing_item, new_item);
                         *existing_item = new_item;
                         return;
@@ -83,27 +86,56 @@ impl Module<'hir> {
                         // just keep `existing_item` and return at once
                         return;
                     }
+                    (true, true) => {
+                        // both `existing_item` and `new_item` are from glob
+                        if existing_item.hir_item.def_id == new_item.hir_item.def_id {
+                            // they actually point to same object, it is ok to just keep one of them
+                            return;
+                        } else {
+                            // a "glob import vs glob import in the same module" will raise when actually use these item
+                            // we should accept neither of these two items
+                            to_remove = Some(index);
+                        }
+                    }
                     (false, false) => {
                         // should report "defined multiple time" error before reach this
                         unreachable!()
                     }
                 }
             }
         }
+        if let Some(index) = to_remove {
+            self.items.swap_remove(index);
+            return;
+        }
         // no item with same name and namespace exists, just collect `new_item`
         self.items.push(new_item);
     }
 
     pub(crate) fn push_mod(&mut self, new_mod: Module<'hir>) {
-        if let Some(existing_mod) = self.mods.iter_mut().find(|mod_| mod_.name == new_mod.name) {
+        let mut to_remove = None;
+        if let Some((index, existing_mod)) =
+            self.mods.iter_mut().enumerate().find(|(_, mod_)| mod_.name == new_mod.name)
+        {
             match (existing_mod.from_glob, new_mod.from_glob) {
-                (true, _) => {
+                (true, false) => {
                     // `existing_mod` is from glob, no matter whether `new_mod` is from glob,
                     // `new_mod` should always shadow `existing_mod`
                     debug!("push_mod: {:?} shadowed by {:?}", existing_mod.name, new_mod.name);
                     *existing_mod = new_mod;
                     return;
                 }
+                (true, true) => {
+                    // both `existing_item` and `new_item` are from glob
+                    if existing_mod.id == new_mod.id {
+                        // they actually point to same object, it is ok to just keep one of them
+                        return;
+                    } else {
+                        // a "glob import vs glob import in the same module" will raise when actually use these item
+                        // we should accept neither of these two items
+                        to_remove = Some(index);
+                    }
+                }
                 (false, true) => {
                     // `existing_mod` is not from glob but `new_mod` is,
                     // just keep `existing_mod` and return at once
@@ -115,6 +147,10 @@ impl Module<'hir> {
                 }
             }
         }
+        if let Some(index) = to_remove {
+            self.mods.swap_remove(index);
+            return;
+        }
         // no mod with same name exists, just collect `new_mod`
         self.mods.push(new_mod);
     }

src/test/rustdoc/glob-shadowing.rs

@@ -1,11 +1,11 @@
 // @has 'glob_shadowing/index.html'
 // @count - '//tr[@class="module-item"]' 4
 // @!has - '//tr[@class="module-item"]' 'sub1::describe'
+// @!has - '//tr[@class="module-item"]' 'sub1::describe2'
 // @has - '//tr[@class="module-item"]' 'mod::prelude'
 // @has - '//tr[@class="module-item"]' 'sub2::describe'
 // @has - '//tr[@class="module-item"]' 'sub1::Foo (struct)'
 // @has - '//tr[@class="module-item"]' 'mod::Foo (function)'
-
 // @has 'glob_shadowing/fn.describe.html'
 // @has - '//div[@class="docblock"]' 'sub2::describe'
 
@@ -22,9 +22,16 @@ mod sub1 {
         pub use super::describe;
     }
 
-    // this should not be shadowed, because sub1::Foo and mod::Foo are in different namespace
+    // this should *not* be shadowed, because sub1::Foo and mod::Foo are in different namespace
     /// sub1::Foo (struct)
     pub struct Foo;
+
+    // this should be shadowed, 
+    // because both sub1::describe2 and sub3::describe2 are from glob reexport
+    /// sub1::describe2
+    pub fn describe2() -> &'static str {
+        "sub1::describe2"
+    }
 }
 
 mod sub2 {
@@ -34,6 +41,15 @@ mod sub2 {
     }
 }
 
+mod sub3 {
+    // this should be shadowed
+    // because both sub1::describe2 and sub3::describe2 are from glob reexport
+    /// sub3::describe2
+    pub fn describe2() -> &'static str {
+        "sub3::describe2"
+    }
+}
+
 /// mod::prelude
 pub mod prelude {}
 
@@ -45,3 +61,6 @@ pub use sub2::describe;
 
 #[doc(inline)]
 pub use sub1::*;
+
+#[doc(inline)]
+pub use sub3::*;