Rename DummyAstNode as ClobberDummy.

This makes the connection to `visit_clobber` more obvious.

Author: nnethercote

compiler/rustc_ast/src/mut_visit.rs

@@ -313,7 +313,7 @@ pub trait MutVisitor: Sized {
 /// method.
 //
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_clobber<T: DummyAstNode>(t: &mut T, f: impl FnOnce(T) -> T) {
+pub fn visit_clobber<T: ClobberDummy>(t: &mut T, f: impl FnOnce(T) -> T) {
     unsafe {
         // Safe because `t` is used in a read-only fashion by `read()` before
         // being overwritten by `write()`.
@@ -1607,23 +1607,23 @@ pub fn noop_visit_capture_by<T: MutVisitor>(capture_by: &mut CaptureBy, vis: &mu
 /// to `Default` but not intended for wide use. The value will never be used
 /// meaningfully, it exists just to support unwinding in `visit_clobber` in the
 /// case where its closure panics.
-pub trait DummyAstNode {
+pub trait ClobberDummy {
     fn dummy() -> Self;
 }
 
-impl<T> DummyAstNode for Option<T> {
+impl<T> ClobberDummy for Option<T> {
     fn dummy() -> Self {
         Default::default()
     }
 }
 
-impl<T: DummyAstNode + 'static> DummyAstNode for P<T> {
+impl<T: ClobberDummy + 'static> ClobberDummy for P<T> {
     fn dummy() -> Self {
-        P(DummyAstNode::dummy())
+        P(ClobberDummy::dummy())
     }
 }
 
-impl DummyAstNode for Item {
+impl ClobberDummy for Item {
     fn dummy() -> Self {
         Item {
             attrs: Default::default(),
@@ -1641,7 +1641,7 @@ impl DummyAstNode for Item {
     }
 }
 
-impl DummyAstNode for Expr {
+impl ClobberDummy for Expr {
     fn dummy() -> Self {
         Expr {
             id: DUMMY_NODE_ID,
@@ -1653,7 +1653,7 @@ impl DummyAstNode for Expr {
     }
 }
 
-impl DummyAstNode for Ty {
+impl ClobberDummy for Ty {
     fn dummy() -> Self {
         Ty {
             id: DUMMY_NODE_ID,
@@ -1664,7 +1664,7 @@ impl DummyAstNode for Ty {
     }
 }
 
-impl DummyAstNode for Pat {
+impl ClobberDummy for Pat {
     fn dummy() -> Self {
         Pat {
             id: DUMMY_NODE_ID,
@@ -1675,13 +1675,13 @@ impl DummyAstNode for Pat {
     }
 }
 
-impl DummyAstNode for Stmt {
+impl ClobberDummy for Stmt {
     fn dummy() -> Self {
         Stmt { id: DUMMY_NODE_ID, kind: StmtKind::Empty, span: Default::default() }
     }
 }
 
-impl DummyAstNode for Crate {
+impl ClobberDummy for Crate {
     fn dummy() -> Self {
         Crate {
             attrs: Default::default(),
@@ -1693,7 +1693,7 @@ impl DummyAstNode for Crate {
     }
 }
 
-impl<N: DummyAstNode, T: DummyAstNode> DummyAstNode for crate::ast_traits::AstNodeWrapper<N, T> {
+impl<N: ClobberDummy, T: ClobberDummy> ClobberDummy for crate::ast_traits::AstNodeWrapper<N, T> {
     fn dummy() -> Self {
         crate::ast_traits::AstNodeWrapper::new(N::dummy(), T::dummy())
     }

compiler/rustc_expand/src/expand.rs

@@ -1556,7 +1556,7 @@ impl InvocationCollectorNode for AstNodeWrapper<P<ast::Expr>, OptExprTag> {
 /// This struct is a hack to workaround unstable of `stmt_expr_attributes`.
 /// It can be removed once that feature is stabilized.
 struct MethodReceiverTag;
-impl DummyAstNode for MethodReceiverTag {
+impl ClobberDummy for MethodReceiverTag {
     fn dummy() -> MethodReceiverTag {
         MethodReceiverTag
     }
@@ -1822,7 +1822,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
         }
     }
 
-    fn visit_node<Node: InvocationCollectorNode<OutputTy = Node> + DummyAstNode>(
+    fn visit_node<Node: InvocationCollectorNode<OutputTy = Node> + ClobberDummy>(
         &mut self,
         node: &mut Node,
     ) {