Fix missing JSDoc comments on destructured interface properties

internal/fourslash/tests/destructuredInterfaceJSDoc_test.go

@@ -0,0 +1,81 @@
+package fourslash_test
+
+import (
+	"testing"
+
+	"github.com/microsoft/typescript-go/internal/fourslash"
+	"github.com/microsoft/typescript-go/internal/testutil"
+)
+
+func TestDestructuredInterfaceJSDoc(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+interface FooBar {
+    /** foo comment */
+    foo: number;
+    /** bar comment */
+    bar: string;
+    /** baz comment */
+    baz: string;
+}
+
+declare const fubar: FooBar;
+
+const {/*1*/foo, /*2*/bar, /*3*/baz: /*4*/biz} = fubar;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "1", "const foo: number", "foo comment")
+	f.VerifyQuickInfoAt(t, "2", "const bar: string", "bar comment")
+	f.VerifyQuickInfoAt(t, "3", "(property) FooBar.baz: string", "baz comment")
+	f.VerifyQuickInfoAt(t, "4", "const biz: string", "baz comment")
+}
+
+func TestDestructuredInterfaceJSDocWithRename(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+interface FooBar {
+    /** foo comment */
+    foo: number;
+    /** bar comment */
+    bar: string;
+}
+
+declare const fubar: FooBar;
+
+const {foo: /*1*/myFoo, bar: /*2*/myBar} = fubar;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	f.VerifyQuickInfoAt(t, "1", "const myFoo: number", "foo comment")
+	f.VerifyQuickInfoAt(t, "2", "const myBar: string", "bar comment")
+}
+
+func TestDestructuredWithOwnJSDoc(t *testing.T) {
+	t.Parallel()
+	defer testutil.RecoverAndFail(t, "Panic on fourslash test")
+	const content = `
+interface Foo {
+    /** This is bar from the interface */
+    bar: string;
+    /** This is baz from the interface */
+    baz: number;
+}
+
+declare var foo: Foo;
+
+/** Comment on the variable statement. */
+const {
+    /** Comment on bar destructuring. */ /*1*/bar,
+    /** Comment on baz destructuring. */ /*2*/baz
+} = foo;
+`
+	f, done := fourslash.NewFourslash(t, nil /*capabilities*/, content)
+	defer done()
+	// When binding elements have their own JSDoc, TypeScript doesn't currently show it in hover
+	// Instead, it falls back to the property's JSDoc from the interface
+	f.VerifyQuickInfoAt(t, "1", "const bar: string", "This is bar from the interface")
+	f.VerifyQuickInfoAt(t, "2", "const baz: number", "This is baz from the interface")
+}

internal/ls/hover.go

@@ -67,16 +67,40 @@ func (l *LanguageService) getQuickInfoAndDocumentationForSymbol(c *checker.Check
 	if quickInfo == "" {
 		return "", ""
 	}
-	return quickInfo, l.getDocumentationFromDeclaration(c, declaration, contentFormat)
+	return quickInfo, l.getDocumentationFromDeclaration(c, symbol, declaration, node, contentFormat)
 }
 
-func (l *LanguageService) getDocumentationFromDeclaration(c *checker.Checker, declaration *ast.Node, contentFormat lsproto.MarkupKind) string {
+func (l *LanguageService) getDocumentationFromDeclaration(c *checker.Checker, symbol *ast.Symbol, declaration *ast.Node, location *ast.Node, contentFormat lsproto.MarkupKind) string {
 	if declaration == nil {
 		return ""
 	}
+
 	isMarkdown := contentFormat == lsproto.MarkupKindMarkdown
 	var b strings.Builder
-	if jsdoc := getJSDocOrTag(c, declaration); jsdoc != nil && !containsTypedefTag(jsdoc) {
+	jsdoc := getJSDocOrTag(c, declaration)
+
+	// Handle binding elements specially (variables created from destructuring) - we need to get the documentation from the property type
+	// If the binding element doesn't have its own JSDoc, fall back to the property's JSDoc
+	if jsdoc == nil && symbol != nil && symbol.ValueDeclaration != nil && ast.IsBindingElement(symbol.ValueDeclaration) && ast.IsIdentifier(location) {
+		bindingElement := symbol.ValueDeclaration
+		parent := bindingElement.Parent
+		name := bindingElement.PropertyName()
+		if name == nil {
+			name = bindingElement.Name()
+		}
+		if ast.IsIdentifier(name) && ast.IsObjectBindingPattern(parent) {
+			propertyName := name.Text()
+			objectType := c.GetTypeAtLocation(parent)
+			if objectType != nil {
+				propertySymbol := findPropertyInType(c, objectType, propertyName)
+				if propertySymbol != nil && propertySymbol.ValueDeclaration != nil {
+					jsdoc = getJSDocOrTag(c, propertySymbol.ValueDeclaration)
+				}
+			}
+		}
+	}
+
+	if jsdoc != nil && !containsTypedefTag(jsdoc) {
 		l.writeComments(&b, c, jsdoc.Comments(), isMarkdown)
 		if jsdoc.Kind == ast.KindJSDoc {
 			if tags := jsdoc.AsJSDoc().Tags; tags != nil {
@@ -582,6 +606,20 @@ func writeQuotedString(b *strings.Builder, str string, quote bool) {
 	}
 }
 
+// findPropertyInType finds a property in a type, handling union types by searching constituent types
+func findPropertyInType(c *checker.Checker, objectType *checker.Type, propertyName string) *ast.Symbol {
+	// For union types, try to find the property in any of the constituent types
+	if objectType.IsUnion() {
+		for _, t := range objectType.Types() {
+			if prop := c.GetPropertyOfType(t, propertyName); prop != nil {
+				return prop
+			}
+		}
+		return nil
+	}
+	return c.GetPropertyOfType(objectType, propertyName)
+}
+
 func getEntityNameString(name *ast.Node) string {
 	var b strings.Builder
 	writeEntityNameParts(&b, name)

internal/ls/signaturehelp.go

@@ -428,7 +428,7 @@ func (l *LanguageService) getSignatureHelpItem(candidate *checker.Signature, isT
 	// Generate documentation from the signature's declaration
 	var documentation *string
 	if declaration := candidate.Declaration(); declaration != nil {
-		doc := l.getDocumentationFromDeclaration(c, declaration, docFormat)
+		doc := l.getDocumentationFromDeclaration(c, nil, declaration, nil, docFormat)
 		if doc != "" {
 			documentation = &doc
 		}

testdata/baselines/reference/fourslash/quickInfo/quickInfoForObjectBindingElementName03.baseline

@@ -14,7 +14,7 @@
 // | ```tsx
 // | var foo: string
 // | ```
-// | 
+// | A description of foo
 // | ----------------------------------------------------------------------
 // }
 [
@@ -31,7 +31,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nvar foo: string\n```\n"
+        "value": "```tsx\nvar foo: string\n```\nA description of foo"
       },
       "range": {
         "start": {

testdata/baselines/reference/fourslash/quickInfo/quickInfoForObjectBindingElementName04.baseline

@@ -19,15 +19,15 @@
 // | ```tsx
 // | var a: { b: string; }
 // | ```
-// | 
+// | A description of 'a'
 // | ----------------------------------------------------------------------
 //     b;
 //     ^
 // | ----------------------------------------------------------------------
 // | ```tsx
 // | var b: string
 // | ```
-// | 
+// | A description of 'b'
 // | ----------------------------------------------------------------------
 // }
 [
@@ -44,7 +44,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nvar a: { b: string; }\n```\n"
+        "value": "```tsx\nvar a: { b: string; }\n```\nA description of 'a'"
       },
       "range": {
         "start": {
@@ -71,7 +71,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nvar b: string\n```\n"
+        "value": "```tsx\nvar b: string\n```\nA description of 'b'"
       },
       "range": {
         "start": {

testdata/baselines/reference/fourslash/quickInfo/quickInfoForObjectBindingElementName05.baseline

@@ -17,7 +17,7 @@
 // | ```tsx
 // | var a: string | number
 // | ```
-// | 
+// | A description of a
 // | ----------------------------------------------------------------------
 // }
 [
@@ -34,7 +34,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nvar a: string | number\n```\n"
+        "value": "```tsx\nvar a: string | number\n```\nA description of a"
       },
       "range": {
         "start": {

testdata/baselines/reference/fourslash/quickInfo/quickInfoForObjectBindingElementName06.baseline

@@ -23,7 +23,7 @@
 // | ```tsx
 // | const isBar: boolean
 // | ```
-// | 
+// | Thing is a baz
 // | ----------------------------------------------------------------------
 [
   {
@@ -39,7 +39,7 @@
     "item": {
       "contents": {
         "kind": "markdown",
-        "value": "```tsx\nconst isBar: boolean\n```\n"
+        "value": "```tsx\nconst isBar: boolean\n```\nThing is a baz"
       },
       "range": {
         "start": {