diff --git a/scripts/processDiagnosticMessages.ts b/scripts/processDiagnosticMessages.ts
index 0a81b993616..e40f119b382 100644
--- a/scripts/processDiagnosticMessages.ts
+++ b/scripts/processDiagnosticMessages.ts
@@ -10,10 +10,6 @@ interface InputDiagnosticMessageTable {
     [msg: string]: DiagnosticDetails;
 }
 
-interface IIndexable<V> {
-    [key: string]: V;
-}
-
 function main(): void {
     var sys = ts.sys;
     if (sys.args.length < 1) {
@@ -25,21 +21,42 @@ function main(): void {
     var inputFilePath = sys.args[0].replace(/\\/g, "/");
     var inputStr = sys.readFile(inputFilePath);
     
-    var diagnosticMesages: InputDiagnosticMessageTable = JSON.parse(inputStr);
+    var diagnosticMessages: InputDiagnosticMessageTable = JSON.parse(inputStr);
 
-    var names = Utilities.getObjectKeys(diagnosticMesages);
+    var names = Utilities.getObjectKeys(diagnosticMessages);
     var nameMap = buildUniqueNameMap(names);
 
-    var infoFileOutput = buildInfoFileOutput(diagnosticMesages, nameMap);
-    
+    var infoFileOutput = buildInfoFileOutput(diagnosticMessages, nameMap);
+    checkForUniqueCodes(names, diagnosticMessages);
+
     // TODO: Fix path joining
     var inputDirectory = inputFilePath.substr(0,inputFilePath.lastIndexOf("/"));
     var fileOutputPath = inputDirectory + "/diagnosticInformationMap.generated.ts";
     sys.writeFile(fileOutputPath, infoFileOutput);
 }
 
-function buildUniqueNameMap(names: string[]): IIndexable<string> {
-    var nameMap: IIndexable<string> = {};
+function checkForUniqueCodes(messages: string[], diagnosticTable: InputDiagnosticMessageTable) {
+    const originalMessageForCode: string[] = [];
+    
+    for (const currentMessage of messages) {
+        const code = diagnosticTable[currentMessage].code;
+
+        if (code in originalMessageForCode) {
+            const originalMessage = originalMessageForCode[code];
+            ts.sys.write("\x1b[93m"); // High intensity yellow.
+            ts.sys.write("Warning");
+            ts.sys.write("\x1b[0m");  // Reset formatting.
+            ts.sys.write(`: Diagnostic code '${code}' conflicts between "${originalMessage}" and "${currentMessage}".`);
+            ts.sys.write(ts.sys.newLine + ts.sys.newLine);
+        }
+        else {
+            originalMessageForCode[code] = currentMessage;
+        }
+    }
+}
+
+function buildUniqueNameMap(names: string[]): ts.Map<string> {
+    var nameMap: ts.Map<string> = {};
 
     var uniqueNames = NameGenerator.ensureUniqueness(names, /* isCaseSensitive */ false, /* isFixed */ undefined);
 
@@ -50,7 +67,7 @@ function buildUniqueNameMap(names: string[]): IIndexable<string> {
     return nameMap;
 }
 
-function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: IIndexable<string>): string {
+function buildInfoFileOutput(messageTable: InputDiagnosticMessageTable, nameMap: ts.Map<string>): string {
     var result =
         '// <auto-generated />\r\n' +
         '/// <reference path="types.ts" />\r\n' +
@@ -172,7 +189,7 @@ module Utilities {
     }
 
     // Like Object.keys
-    export function getObjectKeys(obj: any): string[]{
+    export function getObjectKeys(obj: any): string[] {
         var result: string[] = [];
 
         for (var name in obj) {