2 files changed, 26 insertions, 0 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 9853b0097..a3662702a 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -212,22 +212,42 @@ struct SemanticsDeclModifiersVisitor : public SemanticsDeclVisitorBase,
         // Export'd/Extern'd variables must be `const`, otherwise we may have a mismatch
         // causing errors.
         bool hasConst = false;
+        bool hasUniform = false;
         bool hasExportOrExtern = false;
         bool hasStatic = false;
+        bool hasSpecializationConstant = false;
         for (auto m : decl->modifiers)
         {
             if (as<ExternModifier>(m) || as<HLSLExportModifier>(m))
                 hasExportOrExtern = true;
             else if (as<ConstModifier>(m))
                 hasConst = true;
+            else if (as<HLSLUniformModifier>(m))
+                hasUniform = true;
             else if (as<HLSLStaticModifier>(m))
                 hasStatic = true;
+            else if (as<SpecializationConstantAttribute>(m) || as<VkConstantIdAttribute>(m))
+                hasSpecializationConstant = true;
         }
         if (hasExportOrExtern && hasConst != hasStatic)
             getSink()->diagnose(
                 decl,
                 Diagnostics::ExternAndExportVarDeclMustBeConst,
                 decl->getName());
+
+
+        // Global const or uniform variables with initializers must be static
+        // In HLSL, const global variables without static are uniform parameters
+        // that cannot have default values
+        // Exception: specialization constants are allowed to have initializers
+        if (isGlobalDecl(decl) && (hasConst || hasUniform) && !hasStatic &&
+            !hasSpecializationConstant && decl->initExpr)
+        {
+            getSink()->diagnose(
+                decl,
+                Diagnostics::constGlobalVarWithInitRequiresStatic,
+                decl->getName());
+        }
     }
 
     void visitDecl(Decl* decl) { checkModifiers(decl); }
diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index c549ccca3..3d584679e 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -1508,6 +1508,12 @@ DIAGNOSTIC(
     ExternAndExportVarDeclMustBeConst,
     "extern and export variables must be static const: '$0'")
 
+DIAGNOSTIC(
+    31224,
+    Error,
+    constGlobalVarWithInitRequiresStatic,
+    "global const variable with initializer must be declared static: '$0'")
+
 // Enums
 
 DIAGNOSTIC(32000, Error, invalidEnumTagType, "invalid tag type for 'enum': '$0'")