Rollup merge of rust-lang#59978 - ollie27:rustdoc_default, r=QuietMisdreavus

rustdoc: Remove default keyword from re-exported trait methods

Fixes rust-lang#59977

r? @QuietMisdreavus

As this fixes a stable to beta regression, could it be backported?

Author: Centril

src/librustdoc/clean/mod.rs

@@ -2325,6 +2325,10 @@ impl<'tcx> Clean<Item> for ty::AssociatedItem {
                     } else {
                         hir::Constness::NotConst
                     };
+                    let defaultness = match self.container {
+                        ty::ImplContainer(_) => Some(self.defaultness),
+                        ty::TraitContainer(_) => None,
+                    };
                     MethodItem(Method {
                         generics,
                         decl,
@@ -2334,7 +2338,7 @@ impl<'tcx> Clean<Item> for ty::AssociatedItem {
                             constness,
                             asyncness: hir::IsAsync::NotAsync,
                         },
-                        defaultness: Some(self.defaultness),
+                        defaultness,
                         all_types,
                         ret_types,
                     })

src/test/rustdoc/default-trait-method.rs

@@ -0,0 +1,26 @@
+#![feature(specialization)]
+
+// @has default_trait_method/trait.Item.html
+// @has - '//*[@id="tymethod.foo"]' 'fn foo()'
+// @!has - '//*[@id="tymethod.foo"]' 'default fn foo()'
+// @has - '//*[@id="tymethod.bar"]' 'fn bar()'
+// @!has - '//*[@id="tymethod.bar"]' 'default fn bar()'
+// @has - '//*[@id="method.baz"]' 'fn baz()'
+// @!has - '//*[@id="method.baz"]' 'default fn baz()'
+pub trait Item {
+    fn foo();
+    fn bar();
+    fn baz() {}
+}
+
+// @has default_trait_method/struct.Foo.html
+// @has - '//*[@id="method.foo"]' 'default fn foo()'
+// @has - '//*[@id="method.bar"]' 'fn bar()'
+// @!has - '//*[@id="method.bar"]' 'default fn bar()'
+// @has - '//*[@id="method.baz"]' 'fn baz()'
+// @!has - '//*[@id="method.baz"]' 'default fn baz()'
+pub struct Foo;
+impl Item for Foo {
+    default fn foo() {}
+    fn bar() {}
+}

src/test/rustdoc/default_trait_method.rs

@@ -0,0 +1,16 @@
+#![feature(specialization)]
+
+#![crate_name = "foo"]
+
+pub trait Item {
+    fn foo();
+    fn bar();
+    fn baz() {}
+}
+
+pub struct Foo;
+
+impl Item for Foo {
+    default fn foo() {}
+    fn bar() {}
+}

src/test/rustdoc/inline_cross/auxiliary/default-trait-method.rs

@@ -0,0 +1,20 @@
+// aux-build:default-trait-method.rs
+
+extern crate foo;
+
+// @has default_trait_method/trait.Item.html
+// @has - '//*[@id="tymethod.foo"]' 'fn foo()'
+// @!has - '//*[@id="tymethod.foo"]' 'default fn foo()'
+// @has - '//*[@id="tymethod.bar"]' 'fn bar()'
+// @!has - '//*[@id="tymethod.bar"]' 'default fn bar()'
+// @has - '//*[@id="method.baz"]' 'fn baz()'
+// @!has - '//*[@id="method.baz"]' 'default fn baz()'
+pub use foo::Item;
+
+// @has default_trait_method/struct.Foo.html
+// @has - '//*[@id="method.foo"]' 'default fn foo()'
+// @has - '//*[@id="method.bar"]' 'fn bar()'
+// @!has - '//*[@id="method.bar"]' 'default fn bar()'
+// @has - '//*[@id="method.baz"]' 'fn baz()'
+// @!has - '//*[@id="method.baz"]' 'default fn baz()'
+pub use foo::Foo;