diff --git a/gen/arrays.cpp b/gen/arrays.cpp
index da4196e3..6ad22c49 100644
--- a/gen/arrays.cpp
+++ b/gen/arrays.cpp
@@ -578,20 +578,18 @@ void DtoCatArrays(llvm::Value* arr, Expression* exp1, Expression* exp2)
     assert(t1->ty == t2->ty);
 
     DValue* e1 = exp1->toElem(gIR);
-    llvm::Value* a = e1->getRVal();
-
     DValue* e2 = exp2->toElem(gIR);
-    llvm::Value* b = e2->getRVal();
 
     llvm::Value *len1, *len2, *src1, *src2, *res;
-    len1 = gIR->ir->CreateLoad(DtoGEPi(a,0,0,"tmp"),"tmp");
-    len2 = gIR->ir->CreateLoad(DtoGEPi(b,0,0,"tmp"),"tmp");
+
+    len1 = DtoArrayLen(e1);
+    len2 = DtoArrayLen(e2);
     res = gIR->ir->CreateAdd(len1,len2,"tmp");
 
     llvm::Value* mem = DtoNewDynArray(arr, res, DtoDType(t1->next), false);
 
-    src1 = gIR->ir->CreateLoad(DtoGEPi(a,0,1,"tmp"),"tmp");
-    src2 = gIR->ir->CreateLoad(DtoGEPi(b,0,1,"tmp"),"tmp");
+    src1 = DtoArrayPtr(e1);
+    src2 = DtoArrayPtr(e2);
 
     DtoMemCpy(mem,src1,len1);
     mem = gIR->ir->CreateGEP(mem,len1,"tmp");
diff --git a/ir/irsymbol.cpp b/ir/irsymbol.cpp
index 4b8fcc15..c8d6394c 100644
--- a/ir/irsymbol.cpp
+++ b/ir/irsymbol.cpp
@@ -14,13 +14,13 @@ void IrDsymbol::resetAll()
 
 IrDsymbol::IrDsymbol()
 {
-    list.insert(this);
+    assert(list.insert(this).second);
     reset();
 }
 
 IrDsymbol::IrDsymbol(const IrDsymbol& s)
 {
-    list.insert(this);
+    assert(list.insert(this).second);
     DModule = s.DModule;
     irModule = s.irModule;
     irStruct = s.irStruct;
diff --git a/ir/irtype.cpp b/ir/irtype.cpp
index ffb7c414..12dcc998 100644
--- a/ir/irtype.cpp
+++ b/ir/irtype.cpp
@@ -13,13 +13,13 @@ void IrType::resetAll()
 
 IrType::IrType()
 {
-    list.insert(this);
+    assert(list.insert(this).second);
     reset();
 }
 
 IrType::IrType(const IrType& s)
 {
-    list.insert(this);
+    assert(list.insert(this).second);
     type = s.type;
     vtblType = s.type;
 }