fix: raise SyntaxError for declare before getter/setter

packages/babel-parser/src/parser/error-message.js

@@ -32,6 +32,7 @@ export const ErrorMessages = Object.freeze({
   ConstructorIsAsync: "Constructor can't be an async function",
   ConstructorIsGenerator: "Constructor can't be a generator",
   DeclarationMissingInitializer: "%0 require an initialization value",
+  DeclareAccessor: "'declare' is not allowed in %0ters.",
   DecoratorBeforeExport:
     "Decorators must be placed *before* the 'export' keyword. You can set the 'decoratorsBeforeExport' option to false to use the 'export @decorator class {}' syntax",
   DecoratorConstructor:

packages/babel-parser/src/parser/statement.js

@@ -1509,7 +1509,14 @@ export default class StatementParser extends ExpressionParser {
   // https://tc39.es/proposal-class-fields/#prod-ClassElementName
   parseClassElementName(member: N.ClassMember): N.Expression | N.Identifier {
     const key = this.parsePropertyName(member, /* isPrivateNameAllowed */ true);
+    this.checkClassElementName(member, key);
+    return key;
+  }
 
+  checkClassElementName(
+    member: N.ClassMember,
+    key: N.Expression | N.Identifier,
+  ) {
     if (
       !member.computed &&
       member.static &&
@@ -1525,8 +1532,6 @@ export default class StatementParser extends ExpressionParser {
     ) {
       this.raise(key.start, Errors.ConstructorClassPrivateField);
     }
-
-    return key;
   }
 
   parseClassStaticBlock(

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

@@ -2191,6 +2191,20 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return this.tsParseModifier(["public", "protected", "private"]);
     }
 
+    checkClassElementName(
+      member: N.ClassMember,
+      key: N.Expression | N.Identifier,
+    ) {
+      if (
+        // $FlowIgnore
+        member.declare &&
+        (key.name === "get" || key.name === "set")
+      ) {
+        this.raise(member.start, Errors.DeclareAccessor, key.name);
+      }
+      super.checkClassElementName(member, key);
+    }
+
     parseClassMember(
       classBody: N.ClassBody,
       member: any,

packages/babel-parser/test/fixtures/typescript/class/declare-accessor/input.ts

@@ -0,0 +1,4 @@
+class Foo {
+  declare get foo()
+  declare set foo(v)
+}

packages/babel-parser/test/fixtures/typescript/class/declare-accessor/output.json

@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+  "errors": [
+    "SyntaxError: 'declare' is not allowed in getters. (2:2)",
+    "SyntaxError: 'declare' is not allowed in setters. (3:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":4,"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":54,"loc":{"start":{"line":1,"column":10},"end":{"line":4,"column":1}},
+          "body": [
+            {
+              "type": "TSDeclareMethod",
+              "start":14,"end":31,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":19}},
+              "declare": true,
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":26,"end":29,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":17},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false,
+              "kind": "get",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": []
+            },
+            {
+              "type": "TSDeclareMethod",
+              "start":34,"end":52,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":20}},
+              "declare": true,
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":46,"end":49,"loc":{"start":{"line":3,"column":14},"end":{"line":3,"column":17},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false,
+              "kind": "set",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":50,"end":51,"loc":{"start":{"line":3,"column":18},"end":{"line":3,"column":19},"identifierName":"v"},
+                  "name": "v"
+                }
+              ]
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}