From f89840747316ea9ba764bdc684a920198838685f Mon Sep 17 00:00:00 2001
From: fisker <lionkay@gmail.com>
Date: Sun, 28 Sep 2025 22:05:11 +0800
Subject: [PATCH] fix(typescript-estree): forbid `abstract` modifier in object
 methods

---
 .../fixtures/_error_/abstract-method/fixture.ts      |  1 +
 .../abstract-method/snapshots/1-TSESTree-Error.shot  |  7 +++++++
 .../abstract-method/snapshots/2-Babel-Error.shot     |  8 ++++++++
 .../abstract-method/snapshots/3-Alignment-Error.shot |  4 ++++
 packages/typescript-estree/src/convert.ts            | 12 ++++++++++++
 5 files changed, 32 insertions(+)
 create mode 100644 packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/fixture.ts
 create mode 100644 packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/1-TSESTree-Error.shot
 create mode 100644 packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/2-Babel-Error.shot
 create mode 100644 packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/3-Alignment-Error.shot

diff --git a/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/fixture.ts b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/fixture.ts
new file mode 100644
index 000000000000..8d7ba0694b01
--- /dev/null
+++ b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/fixture.ts
@@ -0,0 +1 @@
+({abstract method(){}})
diff --git a/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/1-TSESTree-Error.shot b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/1-TSESTree-Error.shot
new file mode 100644
index 000000000000..dc431453e57a
--- /dev/null
+++ b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/1-TSESTree-Error.shot
@@ -0,0 +1,7 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`AST Fixtures > expression > ObjectExpression > _error_ > abstract-method > TSESTree - Error`]
+TSError
+> 1 | ({abstract method(){}})
+    |   ^^^^^^^^ 'abstract' modifier cannot be used here.
+  2 |
diff --git a/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/2-Babel-Error.shot b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/2-Babel-Error.shot
new file mode 100644
index 000000000000..b186e7ceed16
--- /dev/null
+++ b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/2-Babel-Error.shot
@@ -0,0 +1,8 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`AST Fixtures > expression > ObjectExpression > _error_ > abstract-method > Babel - Error`]
+BabelError
+> 1 | ({abstract method(){}})
+    |            ^ Unexpected token, expected "," (1:11)
+  2 |
+  
diff --git a/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/3-Alignment-Error.shot b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/3-Alignment-Error.shot
new file mode 100644
index 000000000000..2285aeb1e136
--- /dev/null
+++ b/packages/ast-spec/src/expression/ObjectExpression/fixtures/_error_/abstract-method/snapshots/3-Alignment-Error.shot
@@ -0,0 +1,4 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`AST Fixtures > expression > ObjectExpression > _error_ > abstract-method > Error Alignment`]
+Both errored
diff --git a/packages/typescript-estree/src/convert.ts b/packages/typescript-estree/src/convert.ts
index bec26fede610..23ef63e6a94e 100644
--- a/packages/typescript-estree/src/convert.ts
+++ b/packages/typescript-estree/src/convert.ts
@@ -398,6 +398,18 @@ export class Converter {
           );
         }
       }
+
+      // TODO: There are more cases in `checkGrammarObjectLiteralExpression` in typescript
+      if (
+        modifier.kind === SyntaxKind.AbstractKeyword &&
+        node.kind === SyntaxKind.MethodDeclaration &&
+        node.parent.kind === SyntaxKind.ObjectLiteralExpression
+      ) {
+        this.#throwError(
+          modifier,
+          `'${ts.tokenToString(modifier.kind)}' modifier cannot be used here.`,
+        );
+      }
     }
   }