(ts) Raise syntax error for an abstract method in non-abstract class

packages/babel-parser/src/plugins/typescript/index.js

@@ -85,6 +85,8 @@ const TSErrors = Object.freeze({
     "Tuple members must be labeled with a simple identifier.",
   MixedLabeledAndUnlabeledElements:
     "Tuple members must all have names or all not have names.",
+  NonAbstractClassHasAbstractMethod:
+    "Abstract methods can only appear within an abstract class.",
   OptionalTypeBeforeRequired:
     "A required element cannot follow an optional element.",
   PatternIsOptional:
@@ -1597,6 +1599,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
               cls,
               /* isStatement */ true,
               /* optionalId */ false,
+              /* abstract */ true,
             );
           }
           break;
@@ -2171,6 +2174,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return;
       }
 
+      if (!this.state.inAbstractClass && (member: any).abstract) {
+        this.raise(member.start, TSErrors.NonAbstractClassHasAbstractMethod);
+      }
+
       /*:: invariant(member.type !== "TSIndexSignature") */
 
       super.parseClassMemberWithIsStatic(classBody, member, state, isStatic);
@@ -2824,4 +2831,14 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         this.state.isDeclareContext = oldIsDeclareContext;
       }
     }
+
+    parseClass<T: N.Class>(node: T, ...args: any[]): T {
+      const oldInAbstractClass = this.state.inAbstractClass;
+      this.state.inAbstractClass = !!(node: any).abstract;
+      try {
+        return super.parseClass(node, ...args);
+      } finally {
+        this.state.inAbstractClass = oldInAbstractClass;
+      }
+    }
   };

packages/babel-parser/src/tokenizer/state.js

@@ -65,6 +65,7 @@ export default class State {
   hasFlowComment: boolean = false;
   isIterator: boolean = false;
   isDeclareContext: boolean = false;
+  inAbstractClass: boolean = false;
 
   // For the smartPipelines plugin:
   topicContext: TopicContextState = {

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-1/input.ts

@@ -0,0 +1,3 @@
+class Foo {
+  abstract method();
+}

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-1/output.json

@@ -0,0 +1,49 @@
+{
+  "type": "File",
+  "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Abstract methods can only appear within an abstract class. (2:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":34,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":9,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":9},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":10,"end":34,"loc":{"start":{"line":1,"column":10},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "TSDeclareMethod",
+              "start":14,"end":32,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":20}},
+              "abstract": true,
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":23,"end":29,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":17},"identifierName":"method"},
+                "name": "method"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": []
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-2/input.ts

@@ -0,0 +1,7 @@
+abstract class Foo {
+  method() {
+    return class {
+      abstract m();
+    }
+  }
+}

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-2/output.json

@@ -0,0 +1,89 @@
+{
+  "type": "File",
+  "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "errors": [
+    "SyntaxError: Abstract methods can only appear within an abstract class. (4:6)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":84,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+        "abstract": true,
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":18,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":18},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":19,"end":84,"loc":{"start":{"line":1,"column":19},"end":{"line":7,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":23,"end":82,"loc":{"start":{"line":2,"column":2},"end":{"line":6,"column":3}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":23,"end":29,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":8},"identifierName":"method"},
+                "name": "method"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [],
+              "body": {
+                "type": "BlockStatement",
+                "start":32,"end":82,"loc":{"start":{"line":2,"column":11},"end":{"line":6,"column":3}},
+                "body": [
+                  {
+                    "type": "ReturnStatement",
+                    "start":38,"end":78,"loc":{"start":{"line":3,"column":4},"end":{"line":5,"column":5}},
+                    "argument": {
+                      "type": "ClassExpression",
+                      "start":45,"end":78,"loc":{"start":{"line":3,"column":11},"end":{"line":5,"column":5}},
+                      "id": null,
+                      "superClass": null,
+                      "body": {
+                        "type": "ClassBody",
+                        "start":51,"end":78,"loc":{"start":{"line":3,"column":17},"end":{"line":5,"column":5}},
+                        "body": [
+                          {
+                            "type": "TSDeclareMethod",
+                            "start":59,"end":72,"loc":{"start":{"line":4,"column":6},"end":{"line":4,"column":19}},
+                            "abstract": true,
+                            "static": false,
+                            "key": {
+                              "type": "Identifier",
+                              "start":68,"end":69,"loc":{"start":{"line":4,"column":15},"end":{"line":4,"column":16},"identifierName":"m"},
+                              "name": "m"
+                            },
+                            "computed": false,
+                            "kind": "method",
+                            "id": null,
+                            "generator": false,
+                            "async": false,
+                            "params": []
+                          }
+                        ]
+                      }
+                    }
+                  }
+                ],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-3/input.ts

@@ -0,0 +1 @@
+abstract class C { p = class { abstract method() } }

packages/babel-parser/test/fixtures/typescript/class/abstract-method-in-non-abstract-class-3/output.json

@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":52}},
+  "errors": [
+    "SyntaxError: Abstract methods can only appear within an abstract class. (1:31)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":52}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":52,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":52}},
+        "abstract": true,
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":16,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":16},"identifierName":"C"},
+          "name": "C"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":17,"end":52,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":52}},
+          "body": [
+            {
+              "type": "ClassProperty",
+              "start":19,"end":50,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":50}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":19,"end":20,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":20},"identifierName":"p"},
+                "name": "p"
+              },
+              "computed": false,
+              "value": {
+                "type": "ClassExpression",
+                "start":23,"end":50,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":50}},
+                "id": null,
+                "superClass": null,
+                "body": {
+                  "type": "ClassBody",
+                  "start":29,"end":50,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":50}},
+                  "body": [
+                    {
+                      "type": "TSDeclareMethod",
+                      "start":31,"end":48,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":48}},
+                      "abstract": true,
+                      "static": false,
+                      "key": {
+                        "type": "Identifier",
+                        "start":40,"end":46,"loc":{"start":{"line":1,"column":40},"end":{"line":1,"column":46},"identifierName":"method"},
+                        "name": "method"
+                      },
+                      "computed": false,
+                      "kind": "method",
+                      "id": null,
+                      "generator": false,
+                      "async": false,
+                      "params": []
+                    }
+                  ]
+                }
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/typescript/class/generator-method-with-modifiers/output.json

@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":139,"loc":{"start":{"line":1,"column":0},"end":{"line":9,"column":1}},
+  "errors": [
+    "SyntaxError: Abstract methods can only appear within an abstract class. (5:2)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":139,"loc":{"start":{"line":1,"column":0},"end":{"line":9,"column":1}},

scripts/parser-tests/typescript/allowlist.txt

@@ -4,6 +4,7 @@ ParameterList13.ts
 ParameterList4.ts
 ParameterList5.ts
 ParameterList6.ts
+abstractPropertyNegative.ts
 accessorParameterAccessibilityModifier.ts
 accessorWithoutBody1.ts
 accessorWithoutBody2.ts
@@ -26,6 +27,7 @@ anonClassDeclarationEmitIsAnon.ts
 anyDeclare.ts
 argumentsBindsToFunctionScopeArgumentList.ts
 arrayOfExportedClass.ts
+asiAbstract.ts
 asyncFunctionsAcrossFiles.ts
 augmentExportEquals1.ts
 augmentExportEquals1_1.ts