diff --git a/include/cudaq/Optimizer/Dialect/CC/CCTypes.td b/include/cudaq/Optimizer/Dialect/CC/CCTypes.td
index 18bce4e156a..fa7706a4ac9 100644
--- a/include/cudaq/Optimizer/Dialect/CC/CCTypes.td
+++ b/include/cudaq/Optimizer/Dialect/CC/CCTypes.td
@@ -83,6 +83,7 @@ def cc_StructType : CCType<"Struct", "struct",
   );
 
   let hasCustomAssemblyFormat = 1;
+  let genVerifyDecl = 1;
 
   let builders = [
     TypeBuilder<(ins CArg<"llvm::StringRef">:$name,
@@ -154,6 +155,7 @@ def cc_ArrayType : CCType<"Array", "array"> {
   );
 
   let hasCustomAssemblyFormat = 1;
+  let genVerifyDecl = 1;
 
   let extraClassDeclaration = [{
     using SizeType = std::int64_t;
@@ -249,6 +251,8 @@ def cc_StdVectorType : CCType<"Stdvec", "stdvec", [],
 
   let assemblyFormat = "`<` qualified($elementType) `>`";
 
+  let genVerifyDecl = 1;
+
   let builders = [
     TypeBuilderWithInferredContext<(ins "mlir::Type":$elementType), [{
       return Base::get(elementType.getContext(), elementType);
diff --git a/lib/Frontend/nvqpp/ASTBridge.cpp b/lib/Frontend/nvqpp/ASTBridge.cpp
index 5d33b6d06f4..74ada130f28 100644
--- a/lib/Frontend/nvqpp/ASTBridge.cpp
+++ b/lib/Frontend/nvqpp/ASTBridge.cpp
@@ -430,14 +430,17 @@ namespace cudaq::details {
 
 bool QuakeBridgeVisitor::generateFunctionDeclaration(
     StringRef funcName, const clang::FunctionDecl *x) {
-  auto loc = toLocation(x);
   allowUnknownRecordType = true;
-  if (!TraverseType(x->getType()))
-    emitFatalError(loc, "failed to generate type for kernel function");
+  if (!TraverseType(x->getType())) {
+    reportClangError(x, mangler, "failed to generate type for kernel function");
+    typeStack.clear();
+    return false;
+  }
   allowUnknownRecordType = false;
   if (!doSyntaxChecks(x))
     return false;
   auto funcTy = cast<FunctionType>(popType());
+  auto loc = toLocation(x);
   [[maybe_unused]] auto fnPair = getOrAddFunc(loc, funcName, funcTy);
   assert(fnPair.first && "expected FuncOp to be created");
   if (!isa<clang::CXXMethodDecl>(x) || x->isStatic())
diff --git a/lib/Frontend/nvqpp/ConvertDecl.cpp b/lib/Frontend/nvqpp/ConvertDecl.cpp
index 101e34d653f..1c25ea319e3 100644
--- a/lib/Frontend/nvqpp/ConvertDecl.cpp
+++ b/lib/Frontend/nvqpp/ConvertDecl.cpp
@@ -180,7 +180,15 @@ bool QuakeBridgeVisitor::interceptRecordDecl(clang::RecordDecl *x) {
       // Traverse template argument 0 to get the vector's element type.
       if (!cts || !TraverseType(cts->getTemplateArgs()[0].getAsType()))
         return false;
-      return pushType(cc::StdvecType::get(ctx, popType()));
+      auto ty = popType();
+      if (quake::isQuantumType(ty)) {
+        if (ty == quake::RefType::get(ctx))
+          return pushType(quake::VeqType::getUnsized(ctx));
+        cudaq::emitFatalError(toLocation(x->getSourceRange()),
+                              "std::vector element type is not supported");
+        return false;
+      }
+      return pushType(cc::StdvecType::get(ctx, ty));
     }
     // std::vector<bool>   =>   cc.stdvec<i1>
     if (name.equals("_Bit_reference") || name.equals("__bit_reference")) {
diff --git a/lib/Frontend/nvqpp/ConvertType.cpp b/lib/Frontend/nvqpp/ConvertType.cpp
index d71be7745c7..14d1eaf170f 100644
--- a/lib/Frontend/nvqpp/ConvertType.cpp
+++ b/lib/Frontend/nvqpp/ConvertType.cpp
@@ -242,10 +242,21 @@ bool QuakeBridgeVisitor::VisitRecordDecl(clang::RecordDecl *x) {
   SmallVector<Type> fieldTys =
       lastTypes(std::distance(x->field_begin(), x->field_end()));
   auto [width, alignInBytes] = getWidthAndAlignment(x);
+
+  // This is a struq if it is not empty and all members are quantum references.
   bool isStruq = !fieldTys.empty();
-  for (auto ty : fieldTys)
+  bool quantumMembers = false;
+  for (auto ty : fieldTys) {
+    if (quake::isQuantumType(ty))
+      quantumMembers = true;
     if (!quake::isQuantumReferenceType(ty))
       isStruq = false;
+  }
+  if (quantumMembers && !isStruq) {
+    reportClangError(x, mangler,
+                     "hybrid quantum-classical struct types are not allowed");
+    return false;
+  }
 
   auto ty = [&]() -> Type {
     if (isStruq)
@@ -458,7 +469,16 @@ bool QuakeBridgeVisitor::VisitRValueReferenceType(
 
 bool QuakeBridgeVisitor::VisitConstantArrayType(clang::ConstantArrayType *t) {
   auto size = t->getSize().getZExtValue();
-  return pushType(cc::ArrayType::get(builder.getContext(), popType(), size));
+  auto ty = popType();
+  if (quake::isQuantumType(ty)) {
+    auto *ctx = builder.getContext();
+    if (ty == quake::RefType::get(ctx))
+      return pushType(quake::VeqType::getUnsized(ctx));
+    emitFatalError(builder.getUnknownLoc(),
+                   "array element type is not supported");
+    return false;
+  }
+  return pushType(cc::ArrayType::get(builder.getContext(), ty, size));
 }
 
 bool QuakeBridgeVisitor::pushType(Type t) {
diff --git a/lib/Optimizer/Dialect/CC/CCTypes.cpp b/lib/Optimizer/Dialect/CC/CCTypes.cpp
index e3b98de5e61..5ed781ce997 100644
--- a/lib/Optimizer/Dialect/CC/CCTypes.cpp
+++ b/lib/Optimizer/Dialect/CC/CCTypes.cpp
@@ -8,6 +8,7 @@
 
 #include "cudaq/Optimizer/Dialect/CC/CCTypes.h"
 #include "cudaq/Optimizer/Dialect/CC/CCDialect.h"
+#include "cudaq/Optimizer/Dialect/Quake/QuakeTypes.h"
 #include "llvm/ADT/TypeSwitch.h"
 #include "mlir/IR/Builders.h"
 #include "mlir/IR/DialectImplementation.h"
@@ -103,6 +104,16 @@ cc::StructType::getPreferredAlignment(const DataLayout &dataLayout,
   return getAlignment();
 }
 
+LogicalResult
+cc::StructType::verify(llvm::function_ref<mlir::InFlightDiagnostic()> emitError,
+                       mlir::StringAttr, llvm::ArrayRef<mlir::Type> members,
+                       bool, bool, unsigned long, unsigned int) {
+  for (auto ty : members)
+    if (quake::isQuantumType(ty))
+      return emitError() << "cc.struct may not contain quake types: " << ty;
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // ArrayType
 //===----------------------------------------------------------------------===//
@@ -139,6 +150,24 @@ void cc::ArrayType::print(AsmPrinter &printer) const {
   printer << '>';
 }
 
+LogicalResult
+cc::ArrayType::verify(function_ref<InFlightDiagnostic()> emitError, Type eleTy,
+                      long) {
+  if (quake::isQuantumType(eleTy))
+    return emitError() << "cc.array may not have a quake element type: "
+                       << eleTy;
+  return success();
+}
+
+LogicalResult
+cc::StdvecType::verify(function_ref<InFlightDiagnostic()> emitError,
+                       Type eleTy) {
+  if (quake::isQuantumType(eleTy))
+    return emitError() << "cc.stdvec may not have a quake element type: "
+                       << eleTy;
+  return success();
+}
+
 } // namespace cudaq
 
 //===----------------------------------------------------------------------===//
diff --git a/test/AST-error/struct_quantum_and_classical.cpp b/test/AST-error/struct_quantum_and_classical.cpp
index f62c661f779..ae9f25544a9 100644
--- a/test/AST-error/struct_quantum_and_classical.cpp
+++ b/test/AST-error/struct_quantum_and_classical.cpp
@@ -20,6 +20,7 @@ struct test {
 
 __qpu__ void hello(cudaq::qubit &q) { h(q); }
 
+// expected-error@+1 {{failed to generate type for kernel function}}
 __qpu__ void kernel(test t) {
   h(t.q);
   hello(t.q[0]);