ts: Throw recoverable for duplicates access modifier (#12775)

* Support parsing for duplicates access modifiers

Support parsing for duplicates access modifiers

* Fix lint problems

* Address reviews

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

@@ -36,9 +36,7 @@ type TsModifier =
   | "abstract"
   | "declare"
   | "static"
-  | "public"
+  | N.Accessibility;
-  | "private"
-  | "protected";
 
 function nonNull<T>(x: ?T): T {
   if (x == null) {
@@ -71,6 +69,7 @@ const TSErrors = Object.freeze({
   DeclareFunctionHasImplementation:
     "An implementation cannot be declared in ambient contexts.",
   DuplicateModifier: "Duplicate modifier: '%0'",
+  DuplicateAccessibilityModifier: "Accessibility modifier already seen.",
   EmptyHeritageClauseType: "'%0' list cannot be empty.",
   EmptyTypeArguments: "Type argument list cannot be empty.",
   EmptyTypeParameters: "Type parameter list cannot be empty.",
@@ -146,6 +145,12 @@ function keywordTypeFromName(
   }
 }
 
+function tsIsAccessModifier(modifier: string): boolean %checks {
+  return (
+    modifier === "private" || modifier === "public" || modifier === "protected"
+  );
+}
+
 export default (superClass: Class<Parser>): Class<Parser> =>
   class extends superClass {
     getScopeHandler(): Class<TypeScriptScopeHandler> {
@@ -196,20 +201,31 @@ export default (superClass: Class<Parser>): Class<Parser> =>
      *    this.tsParseModifiers(node, ["public"]);
      *    this.tsParseModifiers(node, ["abstract", "readonly"]);
      */
-    tsParseModifiers<T: TsModifier>(
+    tsParseModifiers(
-      modified: { [key: TsModifier]: ?true },
+      modified: {
-      allowedModifiers: T[],
+        [key: TsModifier]: ?true,
+        accessibility?: N.Accessibility,
+      },
+      allowedModifiers: TsModifier[],
     ): void {
       for (;;) {
         const startPos = this.state.start;
-        const modifier: ?T = this.tsParseModifier(allowedModifiers);
+        const modifier: ?TsModifier = this.tsParseModifier(allowedModifiers);
 
         if (!modifier) break;
 
-        if (Object.hasOwnProperty.call(modified, modifier)) {
+        if (tsIsAccessModifier(modifier)) {
-          this.raise(startPos, TSErrors.DuplicateModifier, modifier);
+          if (modified.accessibility) {
+            this.raise(startPos, TSErrors.DuplicateAccessibilityModifier);
+          } else {
+            modified.accessibility = modifier;
+          }
+        } else {
+          if (Object.hasOwnProperty.call(modified, modifier)) {
+            this.raise(startPos, TSErrors.DuplicateModifier, modifier);
+          }
+          modified[modifier] = true;
         }
-        modified[modifier] = true;
       }
     }
 
@@ -2120,10 +2136,12 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       member: any,
       state: N.ParseClassMemberState,
     ): void {
-      this.tsParseModifiers(member, ["declare"]);
+      this.tsParseModifiers(member, [
-      const accessibility = this.parseAccessModifier();
+        "declare",
-      if (accessibility) member.accessibility = accessibility;
+        "private",
-      this.tsParseModifiers(member, ["declare"]);
+        "public",
+        "protected",
+      ]);
 
       const callParseClassMember = () => {
         super.parseClassMember(classBody, member, state);

packages/babel-parser/test/fixtures/typescript/class/duplicates-accessibility/input.ts

@@ -0,0 +1,7 @@
+class Foo {
+  public public a;
+  private public b;
+  protected private c;
+  public protected d;
+  public protected private e;
+}

packages/babel-parser/test/fixtures/typescript/class/duplicates-accessibility/output.json

@@ -0,0 +1,102 @@
+{
+  "type": "File",
+  "start":0,"end":127,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+  "errors": [
+    "SyntaxError: Accessibility modifier already seen. (2:9)",
+    "SyntaxError: Accessibility modifier already seen. (3:10)",
+    "SyntaxError: Accessibility modifier already seen. (4:12)",
+    "SyntaxError: Accessibility modifier already seen. (5:9)",
+    "SyntaxError: Accessibility modifier already seen. (6:9)",
+    "SyntaxError: Accessibility modifier already seen. (6:19)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":127,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":127,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"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":127,"loc":{"start":{"line":1,"column":10},"end":{"line":7,"column":1}},
+          "body": [
+            {
+              "type": "ClassProperty",
+              "start":14,"end":30,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":18}},
+              "accessibility": "public",
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":28,"end":29,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":17},"identifierName":"a"},
+                "name": "a"
+              },
+              "computed": false,
+              "value": null
+            },
+            {
+              "type": "ClassProperty",
+              "start":33,"end":50,"loc":{"start":{"line":3,"column":2},"end":{"line":3,"column":19}},
+              "accessibility": "private",
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":48,"end":49,"loc":{"start":{"line":3,"column":17},"end":{"line":3,"column":18},"identifierName":"b"},
+                "name": "b"
+              },
+              "computed": false,
+              "value": null
+            },
+            {
+              "type": "ClassProperty",
+              "start":53,"end":73,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":22}},
+              "accessibility": "protected",
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":71,"end":72,"loc":{"start":{"line":4,"column":20},"end":{"line":4,"column":21},"identifierName":"c"},
+                "name": "c"
+              },
+              "computed": false,
+              "value": null
+            },
+            {
+              "type": "ClassProperty",
+              "start":76,"end":95,"loc":{"start":{"line":5,"column":2},"end":{"line":5,"column":21}},
+              "accessibility": "public",
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":93,"end":94,"loc":{"start":{"line":5,"column":19},"end":{"line":5,"column":20},"identifierName":"d"},
+                "name": "d"
+              },
+              "computed": false,
+              "value": null
+            },
+            {
+              "type": "ClassProperty",
+              "start":98,"end":125,"loc":{"start":{"line":6,"column":2},"end":{"line":6,"column":29}},
+              "accessibility": "public",
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":123,"end":124,"loc":{"start":{"line":6,"column":27},"end":{"line":6,"column":28},"identifierName":"e"},
+                "name": "e"
+              },
+              "computed": false,
+              "value": null
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}