diff --git a/src/ast.cpp b/src/ast.cpp
index 96cf25f..2306b52 100644
--- a/src/ast.cpp
+++ b/src/ast.cpp
@@ -171,6 +171,7 @@ namespace lily {
                 new_env->set_parent(env);
                 std::vector<instruction*> new_branch;
                 branch.expr->compile(mgr, new_branch, new_env);
+                new_branch.push_back(mgr.add_instruction<instruction_slide>(1));
                 ijump->instructions.push_back(std::move(new_branch));
 
                 for(int i = 0; i < ccount; i++) {
@@ -179,7 +180,10 @@ namespace lily {
                 }
             } else {
                 pattern_cons* cons_pattern = dynamic_cast<pattern_cons*>(pattern.get());
-                int constructor = std::distance(data->constructors.begin(), data->constructors.find(cons_pattern->name));
+                int constructor;
+                for(auto& pair : data->constructors) {
+                    if(pair.first == cons_pattern->name) constructor = pair.second->id;
+                }
                 if(branched[constructor]) throw error("cannot branch on the same constructor twice");
                 branched[constructor] = true;
 
@@ -193,6 +197,7 @@ namespace lily {
                 std::vector<instruction*> into;
                 into.push_back(mgr.add_instruction<instruction_split>(vcount));
                 branch.expr->compile(mgr, into, env);
+                into.push_back(mgr.add_instruction<instruction_slide>(vcount));
                 ijump->instructions.push_back(std::move(into));
                 ijump->const_instructions[constructor] = ijump->instructions.size() - 1;
             }
diff --git a/src/gmachine.cpp b/src/gmachine.cpp
index 336776d..4becc62 100644
--- a/src/gmachine.cpp
+++ b/src/gmachine.cpp
@@ -147,8 +147,8 @@ namespace lily {
 
     void instruction_op::gen_llvm(llvm_context& ctx) {
         llvm::Value* stack = ctx.get_current_function()->arg_begin();
-        llvm::Value* param1 = builder.CreateCall(stack_pop_func, { stack }, "temp");
         llvm::Value* param2 = builder.CreateCall(stack_pop_func, { stack }, "temp");
+        llvm::Value* param1 = builder.CreateCall(stack_pop_func, { stack }, "temp");
         llvm::Value* param1_node_num = builder.CreatePointerCast(param1, llvm::PointerType::getUnqual(node_num_type), "temp");
         llvm::Value* param2_node_num = builder.CreatePointerCast(param2, llvm::PointerType::getUnqual(node_num_type), "temp");
         llvm::Value* param1_intptr = builder.CreateGEP(param1_node_num, { get_int32_constant(0), get_int32_constant(1) }, "temp");
diff --git a/src/main.cpp b/src/main.cpp
index abdbc4b..3056dfa 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -8,10 +8,12 @@ int main() {
     try {
 
         lily::program_ptr prog = lily::parse(
-                "data Bool = { False, True }\n"
-                "defn if c t e = { case not c of { True -> { t } False -> { e } } }\n"
-                "defn not b = { case b of { True -> { False } False -> { True } } }\n"
-                "defn main = { if True 3 2 }"
+                "data IntPair = { MkPair(Int, Int) }\n"
+                "data IntList = { Nil, Cons(Int, IntList) }"
+                "defn fst p = { case p of { MkPair(a, b) -> { a } } }\n"
+                "defn snd p = { case p of { MkPair(a, b) -> { b } } }\n"
+                "defn sum l = { case l of { Nil -> { 0 } Cons(x, xs) -> { x + sum xs } } }\n"
+                "defn main = { let tl1 = { Cons 1 Nil } in { let tl2 = { Cons 2 tl1 } in { let tl3 = { Cons 3 tl2 } in { sum tl3 } } } }"
                 );
         prog->gen_llvm();
     } catch(lily::error& e) {
diff --git a/src/type_manager.cpp b/src/type_manager.cpp
index 0d962e2..7cc7f2d 100644
--- a/src/type_manager.cpp
+++ b/src/type_manager.cpp
@@ -29,7 +29,6 @@ namespace lily {
 
     type_data* type_manager::create_data_type(const std::string& name) {
         if(type_names.count(name)) throw error("redefinition of type");
-
         auto new_type = std::make_unique<type_data>(next_id++);
         type_data* raw_ptr = new_type.get();
         types.push_back(std::move(new_type));
@@ -43,7 +42,8 @@ namespace lily {
     }
 
     void type_manager::register_constructors(std::shared_ptr<type_env> env) {
-        for(auto& type_ref : types) {
+        for(int i = 0; i < types.size(); i++) {
+            std::unique_ptr<type>& type_ref = types[i];
             type_data* data_type = dynamic_cast<type_data*>(type_ref.get());
             if(!data_type) continue;