Avoid convertExport when there's a non-identifier or a bogus one

Fixes #44105

Author: elibarzilay

src/services/refactors/convertExport.ts

@@ -23,6 +23,9 @@ namespace ts.refactor {
             if (!info) return emptyArray;
 
             if (!isRefactorErrorInfo(info)) {
+                if (!(isIdentifier(info.exportName) && context.program.getTypeChecker().getSymbolAtLocation(info.exportName))) {
+                    return emptyArray;
+                }
                 const action = info.wasDefault ? defaultToNamedAction : namedToDefaultAction;
                 return [{ name: refactorName, description: action.description, actions: [action] }];
             }
@@ -107,8 +110,9 @@ namespace ts.refactor {
     }
 
     function doChange(exportingSourceFile: SourceFile, program: Program, info: ExportInfo, changes: textChanges.ChangeTracker, cancellationToken: CancellationToken | undefined): void {
-        changeExport(exportingSourceFile, info, changes, program.getTypeChecker());
-        changeImports(program, info, changes, cancellationToken);
+        const checker = program.getTypeChecker();
+        changeExport(exportingSourceFile, info, changes, checker);
+        changeImports(program, info, changes, checker, cancellationToken);
     }
 
     function changeExport(exportingSourceFile: SourceFile, { wasDefault, exportNode, exportName }: ExportInfo, changes: textChanges.ChangeTracker, checker: TypeChecker): void {
@@ -152,8 +156,7 @@ namespace ts.refactor {
         }
     }
 
-    function changeImports(program: Program, { wasDefault, exportName, exportingModuleSymbol }: ExportInfo, changes: textChanges.ChangeTracker, cancellationToken: CancellationToken | undefined): void {
-        const checker = program.getTypeChecker();
+    function changeImports(program: Program, { wasDefault, exportName, exportingModuleSymbol }: ExportInfo, changes: textChanges.ChangeTracker, checker: TypeChecker, cancellationToken: CancellationToken | undefined): void {
         const exportSymbol = Debug.checkDefined(checker.getSymbolAtLocation(exportName), "Export name should resolve to a symbol");
         FindAllReferences.Core.eachExportReference(program.getSourceFiles(), checker, cancellationToken, exportSymbol, exportingModuleSymbol, exportName.text, wasDefault, ref => {
             const importingSourceFile = ref.getSourceFile();

tests/cases/fourslash/refactorConvertExport_onlyValidIdentifiers.ts

@@ -0,0 +1,25 @@
+/// <reference path='fourslash.ts' />
+
+// @allowJs: true
+
+// @Filename: /a.js
+/////*[| |]*/ /** x */ export default 1;
+
+// @Filename: /b.js
+/////*[| |]*/ /** x */ export default (1);
+
+// @Filename: /c.js
+/////*[| |]*/ /** x */ export default x;
+
+goTo.eachRange(r => {
+    goTo.selectRange(r);
+    verify.not.refactorAvailable("Convert export");
+});
+
+// goTo.selectRange(test.ranges()[0]);
+// edit.applyRefactor({
+//     refactorName: "Convert export",
+//     actionName: "Convert default export to named export",
+//     actionDescription: "Convert default export to named export",
+//     newContent: { "/a.js": `...` },
+// });