diff --git a/enzyme/Enzyme/AdjointGenerator.h b/enzyme/Enzyme/AdjointGenerator.h
index 9f1d3cd65dfc..a3abf6991e95 100644
--- a/enzyme/Enzyme/AdjointGenerator.h
+++ b/enzyme/Enzyme/AdjointGenerator.h
@@ -4821,7 +4821,7 @@ class AdjointGenerator : public llvm::InstVisitor<AdjointGenerator> {
           if (call.getAttributes().hasParamAttr(i, attr)) {
             if (gutils->getWidth() == 1) {
               structAttrs[args.size()].push_back(call.getParamAttr(i, attr));
-            } else if (attr == "enzymejl_returnRoots") {
+            } else if (attr == std::string("enzymejl_returnRoots")) {
               structAttrs[args.size()].push_back(
                   Attribute::get(call.getContext(), "enzymejl_returnRoots_v"));
             }
@@ -5155,7 +5155,7 @@ class AdjointGenerator : public llvm::InstVisitor<AdjointGenerator> {
             if (gutils->getWidth() == 1) {
               structAttrs[pre_args.size()].push_back(
                   call.getParamAttr(i, attr));
-            } else if (attr == "enzymejl_returnRoots") {
+            } else if (attr == std::string("enzymejl_returnRoots")) {
               structAttrs[pre_args.size()].push_back(
                   Attribute::get(call.getContext(), "enzymejl_returnRoots_v"));
             }
diff --git a/enzyme/Enzyme/EnzymeLogic.cpp b/enzyme/Enzyme/EnzymeLogic.cpp
index 76fc71921654..f930d4e1375b 100644
--- a/enzyme/Enzyme/EnzymeLogic.cpp
+++ b/enzyme/Enzyme/EnzymeLogic.cpp
@@ -3937,14 +3937,40 @@ Function *EnzymeLogic::CreatePrimalAndGradient(
         hasTape = false;
         // res.first.push_back(StructType::get(todiff->getContext(), {}));
       } else {
-        llvm::errs() << "expected args: [";
+        std::string s;
+        llvm::raw_string_ostream ss(s);
+        ss << "Bad function type of custom reverse pass for function "
+           << key.todiff->getName() << " of type "
+           << *key.todiff->getFunctionType() << "\n";
+        ss << "  expected gradient function to have argument types [";
+        bool seen = false;
         for (auto a : res.first) {
-          llvm::errs() << *a << " ";
+          if (seen)
+            ss << ", ";
+          seen = true;
+          ss << *a;
+        }
+        ss << "]\n";
+        ss << "  Instead found " << foundcalled->getName() << " of type "
+           << *foundcalled->getFunctionType() << "\n";
+        Value *toshow = key.todiff;
+        if (context.req) {
+          toshow = context.req;
+          ss << " at context: " << *context.req;
+        } else {
+          ss << *key.todiff << "\n";
+        }
+        if (CustomErrorHandler) {
+          CustomErrorHandler(ss.str().c_str(), wrap(toshow),
+                             ErrorType::NoDerivative, nullptr, wrap(key.todiff),
+                             wrap(context.ip));
+        } else if (context.req) {
+          EmitFailure("NoDerivative", context.req->getDebugLoc(), context.req,
+                      ss.str());
+        } else {
+          assert(0 && "bad type for custom gradient");
+          llvm_unreachable("bad type for custom gradient");
         }
-        llvm::errs() << "]\n";
-        llvm::errs() << *foundcalled << "\n";
-        assert(0 && "bad type for custom gradient");
-        llvm_unreachable("bad type for custom gradient");
       }
 
       auto st = dyn_cast<StructType>(foundcalled->getReturnType());