Handle literal string union complete pattern for JSX attribute snippets (<input type />) (#52562)

Co-authored-by: Andrew Branch <andrewbranch@users.noreply.github.com>

src/compiler/checker.ts

@@ -1727,6 +1727,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         isArrayType,
         isTupleType,
         isArrayLikeType,
+        isEmptyAnonymousObjectType,
         isTypeInvalidDueToUnionDiscriminant,
         getExactOptionalProperties,
         getAllPossiblePropertiesOfTypes,

src/compiler/types.ts

@@ -4946,6 +4946,8 @@ export interface TypeChecker {
     getPromisedTypeOfPromise(promise: Type, errorNode?: Node): Type | undefined;
     /** @internal */
     getAwaitedType(type: Type): Type | undefined;
+    /** @internal */
+    isEmptyAnonymousObjectType(type: Type): boolean;
     getReturnTypeOfSignature(signature: Signature): Type;
     /**
      * Gets the type of a parameter at a given position in a signature.

src/services/completions.ts

@@ -218,6 +218,7 @@ import {
     isStatement,
     isStatic,
     isString,
+    isStringAndEmptyAnonymousObjectIntersection,
     isStringANonContextualKeyword,
     isStringLiteralLike,
     isStringLiteralOrTemplate,
@@ -1442,7 +1443,7 @@ function createCompletionEntry(
             && !(type.flags & TypeFlags.BooleanLike)
             && !(type.flags & TypeFlags.Union && find((type as UnionType).types, type => !!(type.flags & TypeFlags.BooleanLike)))
         ) {
-            if (type.flags & TypeFlags.StringLike || (type.flags & TypeFlags.Union && every((type as UnionType).types, type => !!(type.flags & (TypeFlags.StringLike | TypeFlags.Undefined))))) {
+            if (type.flags & TypeFlags.StringLike || (type.flags & TypeFlags.Union && every((type as UnionType).types, type => !!(type.flags & (TypeFlags.StringLike | TypeFlags.Undefined) || isStringAndEmptyAnonymousObjectIntersection(type))))) {
                 // If is string like or undefined use quotes
                 insertText = `${escapeSnippetText(name)}=${quote(sourceFile, preferences, "$1")}`;
                 isSnippet = true;

src/services/utilities.ts

@@ -342,6 +342,7 @@ import {
     tryCast,
     Type,
     TypeChecker,
+    TypeFlags,
     TypeFormatFlags,
     TypeNode,
     TypeOfExpression,
@@ -2154,6 +2155,17 @@ export function isStringOrRegularExpressionOrTemplateLiteral(kind: SyntaxKind):
     return false;
 }
 
+/** @internal */
+export function isStringAndEmptyAnonymousObjectIntersection(type: Type) {
+    if (!type.isIntersection()) {
+        return false;
+    }
+
+    const { types, checker } = type;
+    return types.length === 2
+        && (types[0].flags & TypeFlags.String) && checker.isEmptyAnonymousObjectType(types[1]);
+}
+
 /** @internal */
 export function isPunctuation(kind: SyntaxKind): boolean {
     return SyntaxKind.FirstPunctuation <= kind && kind <= SyntaxKind.LastPunctuation;