delegation: Implement glob delegation

Author: petrochenkov

compiler/rustc_ast/src/ast.rs

@@ -3110,6 +3110,7 @@ pub struct Fn {
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub enum DelegationKind {
     Single,
+    Glob,
     List(ThinVec<Ident>),
 }
 
@@ -3121,6 +3122,13 @@ pub struct Delegation {
     pub path: Path,
     pub kind: DelegationKind,
     pub body: Option<P<Block>>,
+    pub from_glob: bool,
+}
+
+impl Delegation {
+    pub fn is_glob(&self) -> bool {
+        matches!(self.kind, DelegationKind::Glob)
+    }
 }
 
 #[derive(Clone, Encodable, Decodable, Debug)]

compiler/rustc_ast/src/mut_visit.rs

@@ -1149,12 +1149,12 @@ pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
         }
         ItemKind::MacCall(m) => vis.visit_mac_call(m),
         ItemKind::MacroDef(def) => vis.visit_macro_def(def),
-        ItemKind::Delegation(box Delegation { id, qself, path, kind, body }) => {
+        ItemKind::Delegation(box Delegation { id, qself, path, kind, body, from_glob: _ }) => {
             vis.visit_id(id);
             vis.visit_qself(qself);
             vis.visit_path(path);
             match kind {
-                DelegationKind::Single => {}
+                DelegationKind::Single | DelegationKind::Glob => {}
                 DelegationKind::List(suffixes) => {
                     for ident in suffixes {
                         vis.visit_ident(ident);
@@ -1203,12 +1203,12 @@ pub fn noop_flat_map_assoc_item<T: MutVisitor>(
             visit_opt(ty, |ty| visitor.visit_ty(ty));
         }
         AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
-        AssocItemKind::Delegation(box Delegation { id, qself, path, kind, body }) => {
+        AssocItemKind::Delegation(box Delegation { id, qself, path, kind, body, from_glob: _ }) => {
             visitor.visit_id(id);
             visitor.visit_qself(qself);
             visitor.visit_path(path);
             match kind {
-                DelegationKind::Single => {}
+                DelegationKind::Single | DelegationKind::Glob => {}
                 DelegationKind::List(suffixes) => {
                     for ident in suffixes {
                         visitor.visit_ident(ident);

compiler/rustc_ast/src/visit.rs

@@ -382,13 +382,13 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) -> V::Resu
         }
         ItemKind::MacCall(mac) => try_visit!(visitor.visit_mac_call(mac)),
         ItemKind::MacroDef(ts) => try_visit!(visitor.visit_mac_def(ts, item.id)),
-        ItemKind::Delegation(box Delegation { id, qself, path, kind, body }) => {
+        ItemKind::Delegation(box Delegation { id, qself, path, kind, body, from_glob: _ }) => {
             if let Some(qself) = qself {
                 try_visit!(visitor.visit_ty(&qself.ty));
             }
             try_visit!(visitor.visit_path(path, *id));
             match kind {
-                DelegationKind::Single => {}
+                DelegationKind::Single | DelegationKind::Glob => {}
                 DelegationKind::List(suffixes) => {
                     for ident in suffixes {
                         visitor.visit_ident(*ident);
@@ -790,13 +790,13 @@ pub fn walk_assoc_item<'a, V: Visitor<'a>>(
         AssocItemKind::MacCall(mac) => {
             try_visit!(visitor.visit_mac_call(mac));
         }
-        AssocItemKind::Delegation(box Delegation { id, qself, path, kind, body }) => {
+        AssocItemKind::Delegation(box Delegation { id, qself, path, kind, body, from_glob: _ }) => {
             if let Some(qself) = qself {
                 try_visit!(visitor.visit_ty(&qself.ty));
             }
             try_visit!(visitor.visit_path(path, *id));
             match kind {
-                DelegationKind::Single => {}
+                DelegationKind::Single | DelegationKind::Glob => {}
                 DelegationKind::List(suffixes) => {
                     for ident in suffixes {
                         visitor.visit_ident(*ident);

compiler/rustc_expand/src/base.rs

@@ -728,6 +728,11 @@ pub enum SyntaxExtensionKind {
         /// The produced AST fragment is appended to the input AST fragment.
         Box<dyn MultiItemModifier + sync::DynSync + sync::DynSend>,
     ),
+    GlobDelegation(Box<dyn GlobDelegationExpander + sync::DynSync + sync::DynSend>),
+}
+
+pub trait GlobDelegationExpander {
+    fn expand(&self, ecx: &mut ExtCtxt<'_>) -> ExpandResult<Vec<Ident>, ()>;
 }
 
 /// A struct representing a macro definition in "lowered" form ready for expansion.
@@ -762,7 +767,9 @@ impl SyntaxExtension {
     /// Returns which kind of macro calls this syntax extension.
     pub fn macro_kind(&self) -> MacroKind {
         match self.kind {
-            SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
+            SyntaxExtensionKind::Bang(..)
+            | SyntaxExtensionKind::LegacyBang(..)
+            | SyntaxExtensionKind::GlobDelegation(..) => MacroKind::Bang,
             SyntaxExtensionKind::Attr(..)
             | SyntaxExtensionKind::LegacyAttr(..)
             | SyntaxExtensionKind::NonMacroAttr => MacroKind::Attr,
@@ -1044,6 +1051,13 @@ pub trait ResolverExpand {
 
     /// Tools registered with `#![register_tool]` and used by tool attributes and lints.
     fn registered_tools(&self) -> &RegisteredTools;
+
+    fn glob_delegation_suffixes(
+        &mut self,
+        def_id: DefId,
+        parent_def_id: LocalDefId,
+    ) -> Result<Vec<Ident>, Indeterminate>;
+    fn register_glob_delegation(&mut self, invoc_id: LocalExpnId);
 }
 
 pub trait LintStoreExpand {