AST: Remove some unnecessary boxes

compiler/rustc_ast/src/ast.rs

@@ -2695,7 +2695,7 @@ pub enum ItemKind {
     /// A use declaration item (`use`).
     ///
     /// E.g., `use foo;`, `use foo::bar;` or `use foo::bar as FooBar;`.
-    Use(P<UseTree>),
+    Use(UseTree),
     /// A static item (`static`).
     ///
     /// E.g., `static FOO: i32 = 42;` or `static FOO: &'static str = "bar";`.
@@ -2719,7 +2719,7 @@ pub enum ItemKind {
     /// E.g., `extern {}` or `extern "C" {}`.
     ForeignMod(ForeignMod),
     /// Module-level inline assembly (from `global_asm!()`).
-    GlobalAsm(P<GlobalAsm>),
+    GlobalAsm(GlobalAsm),
     /// A type alias (`type`).
     ///
     /// E.g., `type Foo = Bar<u8>;`.

compiler/rustc_builtin_macros/src/global_asm.rs

@@ -28,7 +28,7 @@ pub fn expand_global_asm<'cx>(
             ident: Ident::invalid(),
             attrs: Vec::new(),
             id: ast::DUMMY_NODE_ID,
-            kind: ast::ItemKind::GlobalAsm(P(global_asm)),
+            kind: ast::ItemKind::GlobalAsm(global_asm),
             vis: ast::Visibility {
                 span: sp.shrink_to_lo(),
                 kind: ast::VisibilityKind::Inherited,

compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -1,5 +1,4 @@
 use rustc_ast as ast;
-use rustc_ast::ptr::P;
 use rustc_expand::base::{ExtCtxt, ResolverExpand};
 use rustc_expand::expand::ExpansionConfig;
 use rustc_session::Session;
@@ -72,11 +71,11 @@ pub fn inject(
         span,
         Ident::invalid(),
         vec![cx.attribute(cx.meta_word(span, sym::prelude_import))],
-        ast::ItemKind::Use(P(ast::UseTree {
+        ast::ItemKind::Use(ast::UseTree {
             prefix: cx.path(span, import_path),
             kind: ast::UseTreeKind::Glob,
             span,
-        })),
+        }),
     );
 
     krate.items.insert(0, use_item);

compiler/rustc_parse/src/parser/item.rs

@@ -225,7 +225,7 @@ impl<'a> Parser<'a> {
                 return Err(e);
             }
 
-            (Ident::invalid(), ItemKind::Use(P(tree)))
+            (Ident::invalid(), ItemKind::Use(tree))
         } else if self.check_fn_front_matter() {
             // FUNCTION ITEM
             let (ident, sig, generics, body) = self.parse_fn(attrs, req_name, lo)?;