diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 9dbce88c32b..102b6b0c670 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -46,7 +46,7 @@ namespace ts {
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
         const modulekind = compilerOptions.module ? compilerOptions.module : languageVersion === ScriptTarget.ES6 ? ModuleKind.ES6 : ModuleKind.None;
-        const allowSyntheticDefaultImports = compilerOptions.hasOwnProperty("allowSyntheticDefaultImports") ? compilerOptions.allowSyntheticDefaultImports : modulekind === ModuleKind.System;
+        const allowSyntheticDefaultImports = typeof compilerOptions.allowSyntheticDefaultImports !== "undefined" ? compilerOptions.allowSyntheticDefaultImports : modulekind === ModuleKind.System;
 
         const emitResolver = createResolver();