Disallow mixing labeled and unlabeled elements

babel · Jun 28, 2020 · ce28128 · ce28128
1 parent 18bcb42
commit ce28128
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Showing 10 changed files with 32 additions and 79 deletions.
diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
@@ -76,8 +76,8 @@ const TSErrors = Object.freeze({
   IndexSignatureHasStatic: "Index signatures cannot have the 'static' modifier",
   OptionalTypeBeforeRequired:
     "A required element cannot follow an optional element.",
-  LabeledElementBeforeUnlabeled:
-    "An unlabeled element cannot follow a labeled element.",
+  MixedLabeledAndUnlabeledElements:
+    "Tuple members must all have names or all not have names.",
   PatternIsOptional:
     "A binding pattern parameter cannot be optional in an implementation signature.",
   PrivateElementHasAbstract:
@@ -636,7 +636,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       //   No mandatory elements may follow optional elements
       //   If there's a rest element, it must be at the end of the tuple
       let seenOptionalElement = false;
-      let seenLabeledElement = false;
+      let labeledElements = null;
       node.elementTypes.forEach(elementNode => {
         const { type } = elementNode;
 
@@ -649,19 +649,32 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           this.raise(elementNode.start, TSErrors.OptionalTypeBeforeRequired);
         }
 
-        if (
-          seenLabeledElement &&
-          !(type === "TSTupleElementType" && elementNode.label)
-        ) {
-          this.raise(elementNode.start, TSErrors.LabeledElementBeforeUnlabeled);
-        }
+        // Flow doesn't support ||=
+        seenOptionalElement =
+          seenOptionalElement ||
+          (type === "TSTupleElementType" && elementNode.optional) ||
+          type === "TSOptionalType";
+
+        // Don't check labels on spread elements
+        if (type === "TSRestType") return;
+
+        const isLabeled = type === "TSTupleElementType" && !!elementNode.label;
 
-        if (type === "TSTupleElementType") {
-          if (elementNode.label) seenLabeledElement = true;
-          if (elementNode.optional) seenOptionalElement = true;
-        } else if (type === "TSOptionalType") {
-          seenOptionalElement = true;
+        if (labeledElements === false && isLabeled) {
+          this.raise(
+            elementNode.start,
+            TSErrors.MixedLabeledAndUnlabeledElements,
+          );
+        } else if (labeledElements === true && !isLabeled) {
+          this.raise(
+            elementNode.start,
+            TSErrors.MixedLabeledAndUnlabeledElements,
+          );
         }
+
+        labeledElements =
+          labeledElements ??
+          (type === "TSTupleElementType" && !!elementNode.label);
       });
 
       return this.finishNode(node, "TSTupleType");

diff --git a/packages/babel-parser/test/fixtures/typescript/types/.tuple-spread-before-labeled/input.ts b/packages/babel-parser/test/fixtures/typescript/types/.tuple-spread-before-labeled/input.ts
@@ -0,0 +1 @@
+type T = [...B, x: A];
diff --git a/...uple-labeled-and-unlabeled-valid/input.ts → ...es/tuple-labeled-after-unlabeled/input.ts b/...uple-labeled-and-unlabeled-valid/input.ts → ...es/tuple-labeled-after-unlabeled/input.ts
diff --git a/...e-labeled-and-unlabeled-valid/output.json → ...tuple-labeled-after-unlabeled/output.json b/...e-labeled-and-unlabeled-valid/output.json → ...tuple-labeled-after-unlabeled/output.json
@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
+  "errors": [
+    "SyntaxError: Tuple members must all have names or all not have names. (1:13)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},

diff --git a/...le-labeled-and-unlabeled-invalid/input.ts → ...s/tuple-labeled-before-unlabeled/input.ts b/...le-labeled-and-unlabeled-invalid/input.ts → ...s/tuple-labeled-before-unlabeled/input.ts
diff --git a/...labeled-and-unlabeled-invalid/output.json → ...uple-labeled-before-unlabeled/output.json b/...labeled-and-unlabeled-invalid/output.json → ...uple-labeled-before-unlabeled/output.json
@@ -2,7 +2,7 @@
   "type": "File",
   "start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
   "errors": [
-    "SyntaxError: An unlabeled element cannot follow a labeled element. (1:16)"
+    "SyntaxError: Tuple members must all have names or all not have names. (1:16)"
   ],
   "program": {
     "type": "Program",

diff --git a/...abel-parser/test/fixtures/typescript/types/tuple-labeled-optional-after-optional/input.ts b/...abel-parser/test/fixtures/typescript/types/tuple-labeled-optional-after-optional/input.ts
diff --git a/...l-parser/test/fixtures/typescript/types/tuple-labeled-optional-after-optional/output.json b/...l-parser/test/fixtures/typescript/types/tuple-labeled-optional-after-optional/output.json
diff --git a/...t/types/tuple-rest-after-labeled/input.ts → ...types/tuple-spread-after-labeled/input.ts b/...t/types/tuple-rest-after-labeled/input.ts → ...types/tuple-spread-after-labeled/input.ts
diff --git a/...ypes/tuple-rest-after-labeled/output.json → ...es/tuple-spread-after-labeled/output.json b/...ypes/tuple-rest-after-labeled/output.json → ...es/tuple-spread-after-labeled/output.json
@@ -1,9 +1,6 @@
 {
   "type": "File",
   "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
-  "errors": [
-    "SyntaxError: An unlabeled element cannot follow a labeled element. (1:16)"
-  ],
   "program": {
     "type": "Program",
     "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},