Fix invalid cast: JSDocSignature is not a SignatureDeclaration (#25734)

src/compiler/parser.ts

@@ -494,9 +494,9 @@ namespace ts {
             case SyntaxKind.JSDocSignature:
                 return visitNodes(cbNode, cbNodes, node.decorators) ||
                     visitNodes(cbNode, cbNodes, node.modifiers) ||
-                    visitNodes(cbNode, cbNodes, (<SignatureDeclaration>node).typeParameters) ||
-                    visitNodes(cbNode, cbNodes, (<SignatureDeclaration>node).parameters) ||
-                    visitNode(cbNode, (<SignatureDeclaration>node).type);
+                    forEach((<JSDocSignature>node).typeParameters, cbNode) ||
+                    forEach((<JSDocSignature>node).parameters, cbNode) ||
+                    visitNode(cbNode, (<JSDocSignature>node).type);
             case SyntaxKind.JSDocTypeLiteral:
                 if ((node as JSDocTypeLiteral).jsDocPropertyTags) {
                     for (const tag of (node as JSDocTypeLiteral).jsDocPropertyTags!) {

tests/cases/fourslash/updateSourceFile_jsdocSignature.ts

@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts' />
+
+/////**
+//// * @callback Cb
+//// * @return {/**/}
+//// */
+////let x;
+
+// Previously this crashed due to an invalid cast in `forEachChild` for `JSDocSignature`.
+
+goTo.marker("");
+edit.insert("number");