diff --git a/include/util.h b/include/util.h
index 63c91d8..cf48fb2 100644
--- a/include/util.h
+++ b/include/util.h
@@ -55,8 +55,18 @@ libab_result libab_copy_string(char** destination, const char* source);
  * @param to_resolve the parsetype to resolve.
  * @param scope the scope to use for resolving the type info.
  */
-libab_result libab_resolve_parsetype(libab_parsetype* to_resolve,
+libab_result libab_resolve_parsetype_inplace(libab_parsetype* to_resolve,
                                      libab_table* scope);
+/**
+ * Resolves the given parsetype, looking through the scope to find
+ * all referenced base types, and creates a copy with these basetypes.
+ * @param to_resolve the parsetype to resolve.
+ * @param scope the scope to use for resolving the type info.
+ * @return the result of the operation.
+ */
+libab_result libab_resolve_parsetype_copy(libab_parsetype* to_resolve,
+                                          libab_table* scope,
+                                          libab_ref* into);
 /**
  * Creates a new type instance, and stores it into the given reference.
  * @param to_instantiate the basetype to instantiate.
@@ -143,6 +153,13 @@ libab_result libab_create_function_list(libab_ref* into, libab_ref* type);
  */
 libab_result libab_put_table_value(libab_table* table, const char* key,
                                    libab_ref* value);
+/**
+ * Gets the basetype of a parsetype.
+ * @param type the parsetype to get the basetype of.
+ * @param scope the scope to use for searches.
+ * @return the basetype.
+ */
+libab_basetype* libab_get_basetype(libab_parsetype* type, libab_table* scope);
 /**
  * Returns the data stored in the given reference to a libab_value.
  * This is not the same as libab_ref_get: libab_ref_get will return directly
diff --git a/src/interpreter.c b/src/interpreter.c
index ff70d48..d754cb8 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -96,23 +96,6 @@ libab_parsetype* _interpreter_search_type_param_raw(libab_ref_trie* params,
     return to_return;
 }
 
-libab_basetype* _interpreter_get_basetype(libab_parsetype* type,
-                                          libab_table* scope) {
-    libab_ref type_param;
-    libab_basetype* to_return;
-    if(type->variant & LIBABACUS_TYPE_F_RESOLVED) {
-        to_return = type->data_u.base;
-    } else {
-        to_return = libab_table_search_basetype(scope, type->data_u.name);
-        if(to_return == NULL) {
-            libab_table_search_type_param(scope, type->data_u.name, &type_param);
-            to_return = libab_ref_get(&type_param);
-            libab_ref_free(&type_param);
-        }
-    }
-    return to_return;
-}
-
 /**
  * Compares the two types, filling in any missing type parameters
  * in the respective type tries.
@@ -162,14 +145,10 @@ libab_result _interpreter_compare_types(libab_ref* left_type,
 
         if (left != NULL && right != NULL) {
             size_t index = 0;
-            libab_basetype* base_left;
-            libab_basetype* base_right;
             libab_ref temp_left;
             libab_ref temp_right;
             
-            base_left = _interpreter_get_basetype(left, libab_ref_get(scope));
-            base_right = _interpreter_get_basetype(right, libab_ref_get(scope));
-            result = (base_left == base_right)
+            result = (left->data_u.base == right->data_u.base)
                          ? LIBAB_SUCCESS
                          : LIBAB_MISMATCHED_TYPE;
             if (result == LIBAB_SUCCESS &&
@@ -222,7 +201,7 @@ libab_result _interpreter_copy_resolved_type(libab_ref* type,
     } else if ((copy = malloc(sizeof(*copy)))) {
         size_t index = 0;
         copy->variant = original->variant;
-        copy->data_u.base = _interpreter_get_basetype(original, libab_ref_get(scope));
+        copy->data_u.base = original->data_u.base;
         if (copy->variant & LIBABACUS_TYPE_F_PARENT) {
             libab_ref child_copy;
             libab_ref temp_child;
@@ -1019,15 +998,30 @@ int _interpreter_compare_function_param(
     return data->variant == TREE_FUN_PARAM;
 }
 
+libab_result _interpreter_resolve_and_insert_param(
+        libab_parsetype* type, libab_table* scope, libab_ref_vec* into) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_ref copy;
+    result = libab_resolve_parsetype_copy(type, scope, &copy);
+    if(result == LIBAB_SUCCESS) {
+        result = libab_ref_vec_insert(into, &copy);
+    }
+    libab_ref_free(&copy);
+    return result;
+}
+
 int _interpreter_foreach_insert_function_param(
         void* data, va_list args) {
     libab_tree* tree = data;
     libab_ref_vec* into = va_arg(args, libab_ref_vec*);
-    return libab_ref_vec_insert(into, &tree->type);
+    libab_ref* scope = va_arg(args, libab_ref*);
+    return _interpreter_resolve_and_insert_param(libab_ref_get(&tree->type),
+                                                 libab_ref_get(scope),
+                                                 into);
 }
 
 libab_result _interpreter_create_function_type(
-        struct interpreter_state* state, libab_tree* tree, libab_parsetype** type) {
+        struct interpreter_state* state, libab_tree* tree, libab_ref* scope, libab_parsetype** type) {
     libab_result result = LIBAB_SUCCESS;
     libab_basetype* funciton_type = libab_get_basetype_function(state->ab);
 
@@ -1041,9 +1035,10 @@ libab_result _interpreter_create_function_type(
 
     if(result == LIBAB_SUCCESS) {
         result = vec_foreach(&tree->children, NULL, _interpreter_compare_function_param, 
-                _interpreter_foreach_insert_function_param, &(*type)->children);
+                _interpreter_foreach_insert_function_param, &(*type)->children, scope);
         if(result == LIBAB_SUCCESS) {
-            result = libab_ref_vec_insert(&(*type)->children, &tree->type);
+            result = _interpreter_resolve_and_insert_param(libab_ref_get(&tree->type), 
+                    libab_ref_get(scope), &(*type)->children);
         }
         if(result != LIBAB_SUCCESS) {
             libab_ref_vec_free(&(*type)->children);
@@ -1059,9 +1054,9 @@ libab_result _interpreter_create_function_type(
 }
 
 libab_result _interpreter_wrap_function_type(
-        struct interpreter_state* state, libab_tree* tree, libab_ref* into) {
+        struct interpreter_state* state, libab_tree* tree, libab_ref* scope, libab_ref* into) {
     libab_parsetype* type;
-    libab_result result = _interpreter_create_function_type(state, tree, &type);
+    libab_result result = _interpreter_create_function_type(state, tree, scope, &type);
 
     if(result == LIBAB_SUCCESS) {
         result = libab_ref_new(into, type, free_parsetype);
@@ -1085,7 +1080,7 @@ libab_result _interpreter_create_function_value(
 
     if(result == LIBAB_SUCCESS) {
         libab_ref_free(&type);
-        result = _interpreter_wrap_function_type(state, tree, &type);
+        result = _interpreter_wrap_function_type(state, tree, scope, &type);
     }
 
     if(result == LIBAB_SUCCESS) {
diff --git a/src/libabacus.c b/src/libabacus.c
index 1a948f7..5b67105 100644
--- a/src/libabacus.c
+++ b/src/libabacus.c
@@ -340,7 +340,7 @@ libab_result libab_create_type(libab* ab, libab_ref* into, const char* type) {
         result = libab_parser_parse_type(&ab->parser, &tokens, type, into);
     }
     if (result == LIBAB_SUCCESS) {
-        result = libab_resolve_parsetype(libab_ref_get(into),
+        result = libab_resolve_parsetype_inplace(libab_ref_get(into),
                                          libab_ref_get(&ab->table));
     }
     ll_foreach(&tokens, NULL, compare_always, libab_lexer_foreach_match_free);
diff --git a/src/util.c b/src/util.c
index 5738e41..e383a52 100644
--- a/src/util.c
+++ b/src/util.c
@@ -45,7 +45,7 @@ libab_result _libab_check_parsetype(libab_parsetype* to_check) {
     libab_result result = LIBAB_SUCCESS;
     return result;
 }
-libab_result libab_resolve_parsetype(libab_parsetype* to_resolve,
+libab_result libab_resolve_parsetype_inplace(libab_parsetype* to_resolve,
                                      libab_table* scope) {
     libab_result result = LIBAB_SUCCESS;
     int resolve_name, check_parents;
@@ -61,7 +61,7 @@ libab_result libab_resolve_parsetype(libab_parsetype* to_resolve,
 
     if (resolve_name && result == LIBAB_SUCCESS) {
         libab_basetype* basetype =
-            libab_table_search_basetype(scope, to_resolve->data_u.name);
+            libab_get_basetype(to_resolve, scope);
         if (basetype) {
             free(to_resolve->data_u.name);
             to_resolve->data_u.base = basetype;
@@ -81,7 +81,7 @@ libab_result libab_resolve_parsetype(libab_parsetype* to_resolve,
 
     if (to_resolve->variant & LIBABACUS_TYPE_F_PARENT) {
         while (result == LIBAB_SUCCESS && index < to_resolve->children.size) {
-            result = libab_resolve_parsetype(
+            result = libab_resolve_parsetype_inplace(
                 libab_ref_get(&to_resolve->children.data[index]), scope);
             index++;
         }
@@ -90,14 +90,61 @@ libab_result libab_resolve_parsetype(libab_parsetype* to_resolve,
     return result;
 }
 
-void _libab_free_parsetype(void* parsetype) {
-    libab_parsetype_free(parsetype);
-    free(parsetype);
-}
+libab_result libab_resolve_parsetype_copy(libab_parsetype* to_resolve,
+                                          libab_table* scope,
+                                          libab_ref* into) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_parsetype* parsetype;
+    if((parsetype = malloc(sizeof(*parsetype)))) {
+        parsetype->variant = to_resolve->variant | LIBABACUS_TYPE_F_RESOLVED;
+    } else {
+        result = LIBAB_MALLOC;
+    }
 
-void _libab_parsetype_free(void* parsetype) {
-    libab_parsetype_free(parsetype);
-    free(parsetype);
+    if(result == LIBAB_SUCCESS) {
+        libab_basetype* parent_basetype = libab_get_basetype(to_resolve, scope);
+        if(parent_basetype) {
+            parsetype->data_u.base = parent_basetype;
+        } else {
+            result = LIBAB_UNKNOWN_TYPE;
+        }
+    }
+
+
+    if(result == LIBAB_SUCCESS && (to_resolve->variant & LIBABACUS_TYPE_F_PARENT)) {
+        result = libab_ref_vec_init(&parsetype->children);
+    }
+
+    if(result == LIBAB_SUCCESS && (to_resolve->variant & LIBABACUS_TYPE_F_PARENT)) {
+        size_t i;
+        libab_ref temp;
+        libab_ref new_type;
+        for(i = 0; i < to_resolve->children.size && result == LIBAB_SUCCESS; i++) {
+            libab_ref_vec_index(&to_resolve->children, i, &temp);
+            result = libab_resolve_parsetype_copy(libab_ref_get(&temp), scope, &new_type);
+            if(result == LIBAB_SUCCESS) {
+                libab_ref_vec_insert(&parsetype->children, &new_type);
+            }
+            libab_ref_free(&new_type);
+            libab_ref_free(&temp);
+        }
+
+        if(result != LIBAB_SUCCESS) {
+            libab_ref_vec_free(&parsetype->children);
+        }
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        result = libab_ref_new(into, parsetype, free_parsetype);
+        if(result != LIBAB_SUCCESS) libab_parsetype_free(parsetype);
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        free(parsetype);
+        libab_ref_null(into);
+    }
+
+    return result;
 }
 
 libab_result libab_instantiate_basetype(libab_basetype* to_instantiate,
@@ -115,7 +162,7 @@ libab_result libab_instantiate_basetype(libab_basetype* to_instantiate,
     }
 
     if (result == LIBAB_SUCCESS) {
-        result = libab_ref_new(into, parsetype, _libab_parsetype_free);
+        result = libab_ref_new(into, parsetype, free_parsetype);
         if (result != LIBAB_SUCCESS) {
             libab_parsetype_free(parsetype);
         }
@@ -332,6 +379,22 @@ libab_result libab_put_table_value(libab_table* table, const char* key,
     return result;
 }
 
+libab_basetype* libab_get_basetype(libab_parsetype* type, libab_table* scope) {
+    libab_ref type_param;
+    libab_basetype* to_return;
+    if(type->variant & LIBABACUS_TYPE_F_RESOLVED) {
+        to_return = type->data_u.base;
+    } else {
+        to_return = libab_table_search_basetype(scope, type->data_u.name);
+        if(to_return == NULL) {
+            libab_table_search_type_param(scope, type->data_u.name, &type_param);
+            to_return = libab_ref_get(&type_param);
+            libab_ref_free(&type_param);
+        }
+    }
+    return to_return;
+}
+
 void* libab_unwrap_value(libab_ref* ref) {
     libab_value* value = libab_ref_get(ref);
     return libab_ref_get(&value->data);