fix(eslint-plugin): [no-deprecated] report usage of deprecated private identifiers (#10844)

* check private variables for being deprecated

* report the node name correctly

Author: ronami

Diff for: packages/eslint-plugin/src/rules/no-deprecated.ts

@@ -17,6 +17,7 @@ import {
 type IdentifierLike =
   | TSESTree.Identifier
   | TSESTree.JSXIdentifier
+  | TSESTree.PrivateIdentifier
   | TSESTree.Super;
 
 type MessageIds = 'deprecated' | 'deprecatedWithReason';
@@ -377,7 +378,7 @@ export default createRule<Options, MessageIds>({
         return;
       }
 
-      const name = node.type === AST_NODE_TYPES.Super ? 'super' : node.name;
+      const name = getReportedNodeName(node);
 
       context.report({
         ...(reason
@@ -400,7 +401,20 @@ export default createRule<Options, MessageIds>({
           checkIdentifier(node);
         }
       },
+      PrivateIdentifier: checkIdentifier,
       Super: checkIdentifier,
     };
   },
 });
+
+function getReportedNodeName(node: IdentifierLike): string {
+  if (node.type === AST_NODE_TYPES.Super) {
+    return 'super';
+  }
+
+  if (node.type === AST_NODE_TYPES.PrivateIdentifier) {
+    return `#${node.name}`;
+  }
+
+  return node.name;
+}

Diff for: packages/eslint-plugin/tests/rules/no-deprecated.test.ts

@@ -363,6 +363,15 @@ exists('/foo');
       declare const test: string;
       const bar = { test };
     `,
+    `
+      class A {
+        #b = () => {};
+
+        c() {
+          this.#b();
+        }
+      }
+    `,
   ],
   invalid: [
     {
@@ -2862,5 +2871,27 @@ class B extends A {
         },
       ],
     },
+    {
+      code: `
+        class A {
+          /** @deprecated */
+          #b = () => {};
+
+          c() {
+            this.#b();
+          }
+        }
+      `,
+      errors: [
+        {
+          column: 18,
+          data: { name: '#b' },
+          endColumn: 20,
+          endLine: 7,
+          line: 7,
+          messageId: 'deprecated',
+        },
+      ],
+    },
   ],
 });