From 85028e146914290bf68a8243ee8dc7f696356d59 Mon Sep 17 00:00:00 2001
From: Cort Stratton <cdwfs@users.noreply.github.com>
Date: Thu, 30 Jun 2016 12:51:10 -0700
Subject: [PATCH] When parsing Vulkan GLSL, suggest
 gl_VertexIndex/gl_InstanceIndex instead of gl_VertexID/gl_InstanceID.

---
 glslang/MachineIndependent/ParseHelper.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/glslang/MachineIndependent/ParseHelper.cpp b/glslang/MachineIndependent/ParseHelper.cpp
index fe22ff80..b01d773f 100644
--- a/glslang/MachineIndependent/ParseHelper.cpp
+++ b/glslang/MachineIndependent/ParseHelper.cpp
@@ -1930,7 +1930,13 @@ void TParseContext::variableCheck(TIntermTyped*& nodePtr)
         return;
 
     if (symbol->getType().getBasicType() == EbtVoid) {
-        error(symbol->getLoc(), "undeclared identifier", symbol->getName().c_str(), "");
+        const char *extraInfoFormat = "";
+        if (spvVersion.vulkan != 0 && symbol->getName() == "gl_VertexID") {
+          extraInfoFormat = "(Did you mean gl_VertexIndex?)";
+        } else if (spvVersion.vulkan != 0 && symbol->getName() == "gl_InstanceID") {
+          extraInfoFormat = "(Did you mean gl_InstanceIndex?)";
+        }
+        error(symbol->getLoc(), "undeclared identifier", symbol->getName().c_str(), extraInfoFormat);
 
         // Add to symbol table to prevent future error messages on the same name
         if (symbol->getName().size() > 0) {