6 files changed, 21 insertions, 8 deletions
diff --git a/source/slang/slang-ast-base.h b/source/slang/slang-ast-base.h
index dea02afbb..04788340a 100644
--- a/source/slang/slang-ast-base.h
+++ b/source/slang/slang-ast-base.h
@@ -9,6 +9,8 @@
 
 #include "slang-serialize-reflection.h"
 
+#include "../core/slang-digest.h"
+
 // This file defines the primary base classes for the hierarchy of
 // AST nodes and related objects. For example, this is where the
 // basic `Decl`, `Stmt`, `Expr`, `type`, etc. definitions come from.
diff --git a/source/slang/slang-ast-type.cpp b/source/slang/slang-ast-type.cpp
index 39b7a8e04..480589af4 100644
--- a/source/slang/slang-ast-type.cpp
+++ b/source/slang/slang-ast-type.cpp
@@ -1089,7 +1089,6 @@ Val* AndType::_substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet su
 
 // ModifiedType
 
-
 void ModifiedType::_toTextOverride(StringBuilder& out)
 {
     for( auto modifier : modifiers )
diff --git a/source/slang/slang-ast-type.h b/source/slang/slang-ast-type.h
index 5bb91e5da..895b64f35 100644
--- a/source/slang/slang-ast-type.h
+++ b/source/slang/slang-ast-type.h
@@ -26,7 +26,6 @@ class InitializerListType : public Type
 {
     SLANG_AST_CLASS(InitializerListType)
 
-    
     // Overrides should be public so base classes can access
     void _toTextOverride(StringBuilder& out);
     Type* _createCanonicalTypeOverride();
@@ -694,7 +693,7 @@ class NamespaceType : public Type
     void _toTextOverride(StringBuilder& out);
     bool _equalsImplOverride(Type* type);
     HashCode _getHashCodeOverride();
-    Type* _createCanonicalTypeOverride();    
+    Type* _createCanonicalTypeOverride();
 };
 
 // The concrete type for a value wrapped in an existential, accessible
diff --git a/source/slang/slang-ast-val.h b/source/slang/slang-ast-val.h
index a67d62e3b..49189f65c 100644
--- a/source/slang/slang-ast-val.h
+++ b/source/slang/slang-ast-val.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include "slang-ast-base.h"
+#include "../core/slang-digest.h"
 
 namespace Slang {
 
@@ -379,7 +380,6 @@ class TaggedUnionSubtypeWitness : public SubtypeWitness
     //
     List<Val*> caseWitnesses;
 
-
     // Overrides should be public so base classes can access
     bool _equalsValOverride(Val* val);
     void _toTextOverride(StringBuilder& out);
diff --git a/source/slang/slang-hash-utils.h b/source/slang/slang-hash-utils.h
index 62232dd21..c354e43f0 100644
--- a/source/slang/slang-hash-utils.h
+++ b/source/slang/slang-hash-utils.h
@@ -29,12 +29,13 @@ namespace Slang
     {
         StringBuilder filename;
 
-        for (Index i = 0; i < 4; ++i)
+        uint8_t* uint8Hash = (uint8_t*)hash.values;
+
+        for (Index i = 0; i < 16; ++i)
         {
-            auto hashSegmentString = String(hash.values[i], 16);
+            auto hashSegmentString = String(uint8Hash[i], 16);
 
-            auto leadingZeroCount = 8 - hashSegmentString.getLength();
-            for (Index j = 0; j < leadingZeroCount; ++j)
+            if (hashSegmentString.getLength() == 1)
             {
                 filename.append("0");
             }
diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 20cad2465..3fb89c549 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -1367,6 +1367,18 @@ void Linkage::updateDependencyBasedHash(
     {
         builder.addToDigest(capability);
     }
+
+    // Add the downstream compiler version (if it exists) to the hash
+    auto passThroughMode = getDownstreamCompilerRequiredForTarget(targetReq->getTarget());
+    auto downstreamCompiler = getSessionImpl()->getOrLoadDownstreamCompiler(passThroughMode, nullptr);
+    if (downstreamCompiler)
+    {
+        ComPtr<ISlangBlob> versionString;
+        if (SLANG_SUCCEEDED(downstreamCompiler->getVersionString(versionString.writeRef())))
+        {
+            builder.addToDigest(versionString);
+        }
+    }
 }
 
 SlangResult Linkage::addSearchPath(