diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index f8bafa7a38f..3536152ee35 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -10661,9 +10661,6 @@ namespace ts {
                 return;
             }
 
-            // Exports should be checked only if enclosing module contains both exported and non exported declarations.
-            // In case if all declarations are non-exported check is unnecessary.
-
             // if localSymbol is defined on node then node itself is exported - check is required
             let symbol = node.localSymbol;
             if (!symbol) {
@@ -10683,9 +10680,9 @@ namespace ts {
 
             // we use SymbolFlags.ExportValue, SymbolFlags.ExportType and SymbolFlags.ExportNamespace
             // to denote disjoint declarationSpaces (without making new enum type).
-            let exportedDeclarationSpaces: SymbolFlags = 0;
-            let nonExportedDeclarationSpaces: SymbolFlags = 0;
-            forEach(symbol.declarations, d => {
+            let exportedDeclarationSpaces = SymbolFlags.None;
+            let nonExportedDeclarationSpaces = SymbolFlags.None;
+            for (let d of symbol.declarations) {
                 let declarationSpaces = getDeclarationSpaces(d);
                 if (getEffectiveDeclarationFlags(d, NodeFlags.Export)) {
                     exportedDeclarationSpaces |= declarationSpaces;
@@ -10693,17 +10690,17 @@ namespace ts {
                 else {
                     nonExportedDeclarationSpaces |= declarationSpaces;
                 }
-            });
+            }
 
             let commonDeclarationSpace = exportedDeclarationSpaces & nonExportedDeclarationSpaces;
 
             if (commonDeclarationSpace) {
                 // declaration spaces for exported and non-exported declarations intersect
-                forEach(symbol.declarations, d => {
+                for (let d of symbol.declarations) {
                     if (getDeclarationSpaces(d) & commonDeclarationSpace) {
                         error(d.name, Diagnostics.Individual_declarations_in_merged_declaration_0_must_be_all_exported_or_all_local, declarationNameToString(d.name));
                     }
-                });
+                }
             }
 
             function getDeclarationSpaces(d: Declaration): SymbolFlags {