Handle literal property names and skip rest in destructured-param signature help

Follow-up to review feedback: the destructured-parameter doc helper rejected
string/numeric property names (`{ "foo": x }`) because of an identifier-only
guard, and it could borrow the documentation of a same-named property for an
object-rest binding (`{ a, ...rest }`). Use isPropertyNameLiteral so quoted and
numeric names resolve while computed/private names are skipped, and skip rest
elements via dotDotDotToken. Extends the fourslash test accordingly.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: DukeDeSouth

src/services/signatureHelp.ts

@@ -50,6 +50,7 @@ import {
     isOmittedExpression,
     isParameter,
     isPropertyAccessExpression,
+    isPropertyNameLiteral,
     isSourceFile,
     isSourceFileJS,
     isSpreadElement,
@@ -823,8 +824,13 @@ function getDestructuredParameterDocumentation(parameter: Symbol, checker: TypeC
     const parts: SymbolDisplayPart[] = [];
     for (const element of declaration.name.elements) {
         if (isOmittedExpression(element)) continue;
+        // A rest element (`...rest`) captures the remaining properties; its name is not a property
+        // of the object type, so never attempt to resolve documentation for it.
+        if (element.dotDotDotToken) continue;
         const nameNode = element.propertyName || element.name;
-        if (!isIdentifier(nameNode)) continue;
+        // Property names may be identifiers, string literals or numeric literals; computed and
+        // private names cannot be resolved statically and are skipped.
+        if (!isPropertyNameLiteral(nameNode)) continue;
         const propertyName = getTextOfIdentifierOrLiteral(nameNode);
         const propertyDocumentation = firstDefined(types, type => {
             const property = type.getProperty(propertyName);

tests/cases/fourslash/signatureHelpJSDocDestructuredParams.ts

@@ -19,6 +19,21 @@
 //// */
 ////function withoutParentDoc({ id, label }) {}
 ////withoutParentDoc(/*2*/);
+////
+/////**
+//// * @param {Object} opts
+//// * @param {string} opts.foo a foo
+//// */
+////function quotedName({ "foo": x }) {}
+////quotedName(/*3*/);
+////
+/////**
+//// * @param {Object} opts
+//// * @param {number} opts.a aaa
+//// * @param {number} opts.rest REST_DOC
+//// */
+////function withRest({ a, ...rest }) {}
+////withRest(/*4*/);
 
 verify.signatureHelp(
     {
@@ -41,4 +56,25 @@ verify.signatureHelp(
             { name: "param", text: [{ text: "opts.label", kind: "parameterName" }, { text: " ", kind: "space" }, { text: "The display label.", kind: "text" }] },
         ],
     },
+    {
+        // Quoted (string-literal) property name resolves its nested @param doc.
+        marker: "3",
+        parameterName: "__0",
+        parameterDocComment: "foo: a foo",
+        tags: [
+            { name: "param", text: [{ text: "opts", kind: "text" }] },
+            { name: "param", text: [{ text: "opts.foo", kind: "parameterName" }, { text: " ", kind: "space" }, { text: "a foo", kind: "text" }] },
+        ],
+    },
+    {
+        // Object-rest binding must not borrow the doc of a same-named property.
+        marker: "4",
+        parameterName: "__0",
+        parameterDocComment: "a: aaa",
+        tags: [
+            { name: "param", text: [{ text: "opts", kind: "text" }] },
+            { name: "param", text: [{ text: "opts.a", kind: "parameterName" }, { text: " ", kind: "space" }, { text: "aaa", kind: "text" }] },
+            { name: "param", text: [{ text: "opts.rest", kind: "parameterName" }, { text: " ", kind: "space" }, { text: "REST_DOC", kind: "text" }] },
+        ],
+    },
 );