diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index f42ca9ffe34..0bedc9f404a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -51,7 +51,7 @@ namespace ts {
         const compilerOptions = host.getCompilerOptions();
         const languageVersion = compilerOptions.target || ScriptTarget.ES3;
         const modulekind = getEmitModuleKind(compilerOptions);
-        const noUnusedIdentifiers = compilerOptions.noUnusedLocals || compilerOptions.noUnusedParameters;
+        const noUnusedIdentifiers = !!compilerOptions.noUnusedLocals || !!compilerOptions.noUnusedParameters;
         const allowSyntheticDefaultImports = typeof compilerOptions.allowSyntheticDefaultImports !== "undefined" ? compilerOptions.allowSyntheticDefaultImports : modulekind === ModuleKind.System;
         const strictNullChecks = compilerOptions.strictNullChecks;
 
@@ -849,6 +849,10 @@ namespace ts {
                 location = location.parent;
             }
 
+            if (result && nameNotFoundMessage && noUnusedIdentifiers) {
+                result.isReferenced = true;
+            }
+
             if (!result) {
                 result = getSymbol(globals, name, meaning);
             }
@@ -899,10 +903,6 @@ namespace ts {
                         error(errorLocation, Diagnostics.Identifier_0_must_be_imported_from_a_module, name);
                     }
                 }
-
-                if (result && noUnusedIdentifiers && !isInAmbientContext(location)) {
-                    result.isReferenced = true;
-                }
             }
             return result;
         }