get appropriate parent jsdoc node for arrow functions

src/services/codefixes/inferFromUsage.ts

@@ -274,7 +274,17 @@ namespace ts.codefix {
             return !!merged;
         }));
         const tag = createJSDocComment(comments.join("\n"), createNodeArray([...(oldTags || emptyArray), ...unmergedNewTags]));
-        changes.insertJsdocCommentBefore(sourceFile, parent, tag);
+        const jsDocNode = parent.kind === SyntaxKind.ArrowFunction ? getJsDocNodeForArrowFunction(parent) : parent;
+        jsDocNode.jsDoc = parent.jsDoc;
+        jsDocNode.jsDocCache = parent.jsDocCache;
+        changes.insertJsdocCommentBefore(sourceFile, jsDocNode, tag);
+    }
+
+    function getJsDocNodeForArrowFunction(signature: ArrowFunction): HasJSDoc {
+        if (signature.parent.kind === SyntaxKind.PropertyDeclaration) {
+            return <HasJSDoc>signature.parent;
+        }
+        return <HasJSDoc>signature.parent.parent;
     }
 
     function tryMergeJsdocTags(oldTag: JSDocTag, newTag: JSDocTag): JSDocTag | undefined {

src/services/textChanges.ts

@@ -340,9 +340,7 @@ namespace ts.textChanges {
         }
 
         public insertJsdocCommentBefore(sourceFile: SourceFile, node: HasJSDoc, tag: JSDoc): void {
-            const fnStart = node.kind === SyntaxKind.ArrowFunction
-                ? node.parent.parent.getStart(sourceFile)
-                : node.getStart(sourceFile);
+            const fnStart = node.getStart(sourceFile);
             if (node.jsDoc) {
                 for (const jsdoc of node.jsDoc) {
                     this.deleteRange(sourceFile, {

tests/cases/fourslash/codeFixInferFromUsageArrowJS.ts

@@ -6,13 +6,22 @@
 // @Filename: test.js
 
 ////const foo = x => x.y + 1;
+////class C {
+////    m = x => x.y + 1;
+////}
 
-verify.codeFix({
-  description: "Infer parameter types from usage",
-  index: 0,
+verify.codeFixAll({
+  fixId: "inferFromUsage",
+  fixAllDescription: "Infer all types from usage",
   newFileContent:
 `/**
  * @param {{ y: number; }} x
  */
-const foo = x => x.y + 1;`,
+const foo = x => x.y + 1;
+class C {
+    /**
+     * @param {{ y: number; }} x
+     */
+    m = x => x.y + 1;
+}`,
 });