DefCollector stuff

Author: BoxyUwU

compiler/rustc_resolve/src/def_collector.rs

@@ -367,15 +367,16 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
     }
 
     fn visit_anon_const(&mut self, constant: &'a AnonConst) {
+        // `MgcaDisambiguation::Direct` is set even when MGCA is disabled, so
+        // to avoid affecting stable we have to feature gate the not creating
+        // anon consts
+        if !self.resolver.tcx.features().min_generic_const_args() {
+            let parent =
+                self.create_def(constant.id, None, DefKind::AnonConst, constant.value.span);
+            return self.with_parent(parent, |this| visit::walk_anon_const(this, constant));
+        }
+
         match constant.mgca_disambiguation {
-            // `MgcaDisambiguation::Direct` is set even when MGCA is disabled, so
-            // to avoid affecting stable we have to feature gate the not creating
-            // anon consts
-            _ if !self.resolver.tcx.features().min_generic_const_args() => {
-                let parent =
-                    self.create_def(constant.id, None, DefKind::AnonConst, constant.value.span);
-                self.with_parent(parent, |this| visit::walk_anon_const(this, constant));
-            }
             MgcaDisambiguation::Direct => self.with_const_arg(ConstArgContext::Direct, |this| {
                 visit::walk_anon_const(this, constant);
             }),
@@ -421,28 +422,23 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
             ExprKind::Struct(_) => return visit::walk_expr(self, expr),
             // FIXME(mgca): we may want to handle block labels in some manner
             ExprKind::Block(block, _) if let [stmt] = block.stmts.as_slice() => match stmt.kind {
-                StmtKind::Let(..) | StmtKind::Item(..) | StmtKind::Semi(..) | StmtKind::Empty => {
-                    return self.with_const_arg(ConstArgContext::NonDirect, |this| {
-                        visit::walk_expr(this, expr)
-                    });
-                }
-
                 // FIXME(mgca): this probably means that mac calls that expand
                 // to semi'd const blocks are handled differently to just writing
                 // out a semi'd const block.
-                StmtKind::Expr(..) | StmtKind::MacCall(..) => {
-                    return visit::walk_expr(self, expr);
+                StmtKind::Expr(..) | StmtKind::MacCall(..) => return visit::walk_expr(self, expr),
+
+                // Fallback to normal behaviour
+                StmtKind::Let(..) | StmtKind::Item(..) | StmtKind::Semi(..) | StmtKind::Empty => {
+                    self.invocation_parent.parent_def
                 }
             },
 
-            _ => {
-                return self.with_const_arg(ConstArgContext::NonDirect, |this| {
-                    visit::walk_expr(this, expr)
-                });
-            }
+            _ => self.invocation_parent.parent_def,
         };
 
         self.with_const_arg(ConstArgContext::NonDirect, |this| {
+            // Note in some cases the `parent_def` here may be the existing parent
+            // and this is actually a no-op `with_parent` call.
             this.with_parent(parent_def, |this| visit::walk_expr(this, expr))
         })
     }