diff --git a/src/compiler/builder.ts b/src/compiler/builder.ts
index 9a60557ae36..0881f68800c 100644
--- a/src/compiler/builder.ts
+++ b/src/compiler/builder.ts
@@ -166,12 +166,16 @@ namespace ts {
                 semanticDiagnosticsPerFile.delete(sourceFile.path);
             }
 
-            newReferences && referencedMap.set(sourceFile.path, newReferences);
+            if (newReferences) {
+                referencedMap.set(sourceFile.path, newReferences);
+            }
             fileInfos.set(sourceFile.path, { version, signature: oldInfo && oldInfo.signature });
         }
 
         // For removed files, remove the semantic diagnostics removed files as changed
-        useOldState && oldState.fileInfos.forEach((_value, path) => !fileInfos.has(path) && semanticDiagnosticsPerFile.delete(path));
+        if (useOldState) {
+            oldState.fileInfos.forEach((_value, path) => !fileInfos.has(path) && semanticDiagnosticsPerFile.delete(path));
+        }
 
         // Set the old state and program to undefined to ensure we arent keeping them alive hence forward
         oldState = undefined;
diff --git a/src/harness/unittests/builder.ts b/src/harness/unittests/builder.ts
index 60297d2b7fc..89b0852bd32 100644
--- a/src/harness/unittests/builder.ts
+++ b/src/harness/unittests/builder.ts
@@ -53,7 +53,9 @@ namespace ts {
             const program = getProgram();
             builderState = createBuilderState(program, builderOptions, builderState);
             const outputFileNames: string[] = [];
-            while (builderState.emitNextAffectedFile(program, fileName => outputFileNames.push(fileName))) { }
+            // tslint:disable-next-line no-empty
+            while (builderState.emitNextAffectedFile(program, fileName => outputFileNames.push(fileName))) {
+            }
             assert.deepEqual(outputFileNames, fileNames);
         };
     }