typescript-eslint · nayounsang · Jun 17, 2025 · Jun 20, 2025 · Jun 20, 2025 · Jun 20, 2025
diff --git a/packages/eslint-plugin/src/util/collectUnusedVariables.ts b/packages/eslint-plugin/src/util/collectUnusedVariables.ts
@@ -1,6 +1,7 @@
 import type {
   ScopeManager,
   ScopeVariable,
+  Variable,
 } from '@typescript-eslint/scope-manager';
 import type { TSESTree } from '@typescript-eslint/utils';
 
@@ -188,7 +189,7 @@ class UnusedVarsVisitor extends Visitor {
           // basic exported variables
           isExported(variable) ||
           // variables implicitly exported via a merged declaration
-          isMergableExported(variable) ||
+          isMergeableExported(variable) ||
           // used variables
           isUsedVariable(variable)
         ) {
@@ -415,6 +416,14 @@ function isSelfReference(
   return false;
 }
 
+/**
+ * @param variable the variable to check
+ * @returns true if it is `isTypeVariable` and `isValueVariable`
+ */
+function isDualPurposeVariable(variable: Variable): boolean {
+  return variable.isTypeVariable && variable.isValueVariable;
+}
+
 const MERGABLE_TYPES = new Set([
   AST_NODE_TYPES.ClassDeclaration,
   AST_NODE_TYPES.FunctionDeclaration,
@@ -426,7 +435,7 @@ const MERGABLE_TYPES = new Set([
  * Determine if the variable is directly exported
  * @param variable the variable to check
  */
-function isMergableExported(variable: ScopeVariable): boolean {
+function isMergeableExported(variable: Variable): boolean {
   // If all of the merged things are of the same type, TS will error if not all of them are exported - so we only need to find one
   for (const def of variable.defs) {
     // parameters can never be exported.
@@ -441,7 +450,10 @@ function isMergableExported(variable: ScopeVariable): boolean {
         def.node.parent?.type === AST_NODE_TYPES.ExportNamedDeclaration) ||
       def.node.parent?.type === AST_NODE_TYPES.ExportDefaultDeclaration
     ) {
-      return true;
+      return !(
+        def.node.type === AST_NODE_TYPES.TSTypeAliasDeclaration &&
+        isDualPurposeVariable(variable)
+      );
     }
   }
 
@@ -453,7 +465,7 @@ function isMergableExported(variable: ScopeVariable): boolean {
  * @param variable eslint-scope variable object.
  * @returns True if the variable is exported, false if not.
  */
-function isExported(variable: ScopeVariable): boolean {
+function isExported(variable: Variable): boolean {
   return variable.defs.some(definition => {
     let node = definition.node;
 
@@ -465,7 +477,15 @@ function isExported(variable: ScopeVariable): boolean {
     }
 
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-    return node.parent!.type.startsWith('Export');
+    const isExportedFlag = node.parent!.type.startsWith('Export');
+
+    return (
+      isExportedFlag &&
+      !(
+        node.type === AST_NODE_TYPES.TSTypeAliasDeclaration &&
+        isDualPurposeVariable(variable)
+      )
+    );
   });
 }
 

diff --git a/packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts b/packages/eslint-plugin/tests/rules/no-unused-vars/no-unused-vars.test.ts
@@ -1715,6 +1715,44 @@ export {};
       ],
       filename: 'foo.d.ts',
     },
+    // https://github.com/typescript-eslint/typescript-eslint/issues/10658
+    {
+      code: `
+const A = 0;
+export type A = typeof A;
+      `,
+      errors: [
+        {
+          data: {
+            action: 'assigned a value',
+            additional: '',
+            varName: 'A',
+          },
+          line: 2,
+          messageId: 'usedOnlyAsType',
+        },
+      ],
+    },
+    {
+      code: `
+function A() {}
+namespace A {
+  export const prop = 1;
+}
+export type A = typeof A;
+      `,
+      errors: [
+        {
+          data: {
+            action: 'defined',
+            additional: '',
+            varName: 'A',
+          },
+          line: 2,
+          messageId: 'usedOnlyAsType',
+        },
+      ],
+    },
   ],
 
   valid: [
@@ -3018,5 +3056,18 @@ declare class Bar {}
       `,
       filename: 'foo.d.ts',
     },
+    {
+      code: `
+const A = 0;
+type A = typeof A;
+export { A };
+      `,
+    },
+    {
+      code: `
+class A {}
+export type B = A;
+      `,
+    },
   ],
 });