2 files changed, 29 insertions, 6 deletions

diff --git a/source/slang/slang-check-shader.cpp b/source/slang/slang-check-shader.cpp
index c588a9018..731619908 100644
--- a/source/slang/slang-check-shader.cpp
+++ b/source/slang/slang-check-shader.cpp
@@ -1216,16 +1216,36 @@ namespace Slang
                 auto specializationArg = args[ii];
                 genericArgs.add(specializationArg.val);
             }
-            ASTBuilder* astBuilder = getLinkage()->getASTBuilder();
-
+            auto astBuilder = getLinkage()->getASTBuilder();
             for (auto constraintDecl : getMembersOfType<GenericTypeConstraintDecl>(
                      getLinkage()->getASTBuilder(), DeclRef<ContainerDecl>(genericDeclRef)))
             {
                 DeclRef<GenericTypeConstraintDecl> constraintDeclRef = astBuilder->getDirectDeclRef(constraintDecl.getDecl());
+                int argIndex = -1;
+                int ii = 0;
+                for (auto member : genericDeclRef.getDecl()->members)
+                {
+                    if (member == constraintDeclRef.getDecl())
+                    {
+                        argIndex = ii;
+                        break;
+                    }
+                    ii++;
+                }
+                if (argIndex == -1)
+                {
+                    SLANG_ASSERT(!"generic parameter not found in generic decl");
+                    continue;
+                }
 
-                auto sub = getSub(astBuilder, constraintDeclRef);
-                auto sup = getSup(astBuilder, constraintDeclRef);
+                auto sub = as<Type>(args[argIndex].val);
+                if (!sub)
+                {
+                    sink->diagnose(constraintDecl, Diagnostics::expectedTypeForSpecializationArg, argIndex);
+                    continue;
+                }
 
+                auto sup = getSup(astBuilder, constraintDeclRef);
                 auto subTypeWitness = visitor.isSubtype(sub, sup);
                 if(subTypeWitness)
                 {
diff --git a/source/slang/slang-ir-specialize.cpp b/source/slang/slang-ir-specialize.cpp
index 3320a7d09..a4985eee4 100644
--- a/source/slang/slang-ir-specialize.cpp
+++ b/source/slang/slang-ir-specialize.cpp
@@ -2381,9 +2381,12 @@ IRInst* specializeGenericImpl(
                 // further specializations from the specialized function will have as simple specialization 
                 // arguments as possible to avoid creating specializations that eventually simplified into 
                 // the same thing.
-                if (auto func = as<IRFunc>(specializedVal))
+                if (context)
                 {
-                    simplifyFunc(context->targetProgram, func, IRSimplificationOptions::getFast());
+                    if (auto func = as<IRFunc>(specializedVal))
+                    {
+                        simplifyFunc(context->targetProgram, func, IRSimplificationOptions::getFast());
+                    }
                 }
 
                 return specializedVal;