[release-4.3] Fix duplicate visit of param tag comments (#44443)

src/compiler/parser.ts

@@ -493,12 +493,12 @@ namespace ts {
             case SyntaxKind.JSDocPropertyTag:
                 return visitNode(cbNode, (node as JSDocTag).tagName) ||
                     ((node as JSDocPropertyLikeTag).isNameFirst
-                        ? visitNode(cbNode, (<JSDocPropertyLikeTag>node).name) ||
-                            visitNode(cbNode, (<JSDocPropertyLikeTag>node).typeExpression) ||
+                        ? visitNode(cbNode, (node as JSDocPropertyLikeTag).name) ||
+                            visitNode(cbNode, (node as JSDocPropertyLikeTag).typeExpression) ||
                             (typeof (node as JSDoc).comment === "string" ? undefined : visitNodes(cbNode, cbNodes, (node as JSDoc).comment as NodeArray<JSDocText | JSDocLink> | undefined))
-                        : visitNode(cbNode, (<JSDocPropertyLikeTag>node).typeExpression) ||
-                            visitNode(cbNode, (<JSDocPropertyLikeTag>node).name)) ||
-                            (typeof (node as JSDoc).comment === "string" ? undefined : visitNodes(cbNode, cbNodes, (node as JSDoc).comment as NodeArray<JSDocText | JSDocLink> | undefined));
+                        : visitNode(cbNode, (node as JSDocPropertyLikeTag).typeExpression) ||
+                            visitNode(cbNode, (node as JSDocPropertyLikeTag).name) ||
+                            (typeof (node as JSDoc).comment === "string" ? undefined : visitNodes(cbNode, cbNodes, (node as JSDoc).comment as NodeArray<JSDocText | JSDocLink> | undefined)));
             case SyntaxKind.JSDocAuthorTag:
                 return visitNode(cbNode, (node as JSDocTag).tagName) ||
                     (typeof (node as JSDoc).comment === "string" ? undefined : visitNodes(cbNode, cbNodes, (node as JSDoc).comment as NodeArray<JSDocText | JSDocLink> | undefined));

src/testRunner/unittests/publicApi.ts

@@ -150,6 +150,24 @@ describe("unittests:: Public APIs:: validateLocaleAndSetLanguage", () => {
             }, errors);
         });
     }
-    ts.supportedLocaleDirectories.forEach(locale => verifyValidateLocale(locale, /*expctedToReadFile*/ true));
-    ["en", "en-us"].forEach(locale => verifyValidateLocale(locale, /*expctedToReadFile*/ false));
+    ts.supportedLocaleDirectories.forEach(locale => verifyValidateLocale(locale, /*expectedToReadFile*/ true));
+    ["en", "en-us"].forEach(locale => verifyValidateLocale(locale, /*expectedToReadFile*/ false));
+});
+
+describe("unittests:: Public APIs :: forEachChild of @param comments in JSDoc", () => {
+    const content = `
+/**
+ * @param The {@link TypeReferencesInAedoc}.
+ */
+var x
+`;
+    const sourceFile = ts.createSourceFile("/file.ts", content, ts.ScriptTarget.ESNext, /*setParentNodes*/ true);
+    const paramTag = sourceFile.getChildren()[0].getChildren()[0].getChildren()[0].getChildren()[0];
+    const kids = paramTag.getChildren();
+    const seen: Set<ts.Node> = new Set();
+    ts.forEachChild(paramTag, n => {
+        assert.strictEqual(/*actual*/ false, seen.has(n), "Found a duplicate-added child");
+        seen.add(n);
+    });
+    assert.equal(5, kids.length);
 });