JavaScriptBench
diff --git a/‎src/compiler/utilities.ts‎
Lines changed: 6 additions & 2 deletions b/‎src/compiler/utilities.ts‎
Lines changed: 6 additions & 2 deletions
@@ -1394,6 +1394,10 @@ namespace ts {
         return SpecialPropertyAssignmentKind.None;
     }
 
+    export function isModuleWithStringLiteralName(node: Node): node is ModuleDeclaration {
+        return isModuleDeclaration(node) && node.name.kind === SyntaxKind.StringLiteral;
+    }
+
     export function getExternalModuleName(node: Node): Expression {
         if (node.kind === SyntaxKind.ImportDeclaration) {
             return (<ImportDeclaration>node).moduleSpecifier;
@@ -1407,8 +1411,8 @@ namespace ts {
         if (node.kind === SyntaxKind.ExportDeclaration) {
             return (<ExportDeclaration>node).moduleSpecifier;
         }
-        if (node.kind === SyntaxKind.ModuleDeclaration && (<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral) {
-            return (<ModuleDeclaration>node).name;
+        if (isModuleWithStringLiteralName(node)) {
+            return node.name;
         }
     }
Original file line number	Diff line number	Diff line change
`@@ -1394,6 +1394,10 @@ namespace ts {`
`1394`	`1394`	`return SpecialPropertyAssignmentKind.None;`
`1395`	`1395`	`}`
`1396`	`1396`
	`1397`	`+ export function isModuleWithStringLiteralName(node: Node): node is ModuleDeclaration {`
	`1398`	`+ return isModuleDeclaration(node) && node.name.kind === SyntaxKind.StringLiteral;`
	`1399`	`+ }`
	`1400`	`+`
`1397`	`1401`	`export function getExternalModuleName(node: Node): Expression {`
`1398`	`1402`	`if (node.kind === SyntaxKind.ImportDeclaration) {`
`1399`	`1403`	`return (<ImportDeclaration>node).moduleSpecifier;`
`@@ -1407,8 +1411,8 @@ namespace ts {`
`1407`	`1411`	`if (node.kind === SyntaxKind.ExportDeclaration) {`
`1408`	`1412`	`return (<ExportDeclaration>node).moduleSpecifier;`
`1409`	`1413`	`}`
`1410`		`- if (node.kind === SyntaxKind.ModuleDeclaration && (<ModuleDeclaration>node).name.kind === SyntaxKind.StringLiteral) {`
`1411`		`- return (<ModuleDeclaration>node).name;`
	`1414`	`+ if (isModuleWithStringLiteralName(node)) {`
	`1415`	`+ return node.name;`
`1412`	`1416`	`}`
`1413`	`1417`	`}`
`1414`	`1418`