diff --git a/vyper/ast/nodes.py b/vyper/ast/nodes.py
index c4bce814a4..fb5fb73592 100644
--- a/vyper/ast/nodes.py
+++ b/vyper/ast/nodes.py
@@ -2,6 +2,7 @@
 import contextlib
 import copy
 import decimal
+import functools
 import operator
 import sys
 import warnings
@@ -341,6 +342,7 @@ def from_node(cls, node: "VyperNode", **kwargs) -> "VyperNode":
         return cls(**ast_struct)
 
     @classmethod
+    @functools.lru_cache(maxsize=None)
     def get_fields(cls) -> set:
         """
         Return a set of field names for this node.
diff --git a/vyper/semantics/analysis/utils.py b/vyper/semantics/analysis/utils.py
index fa4dfcc1d1..abea600d88 100644
--- a/vyper/semantics/analysis/utils.py
+++ b/vyper/semantics/analysis/utils.py
@@ -500,12 +500,14 @@ def get_common_types(*nodes: vy_ast.VyperNode, filter_fn: Callable = None) -> Li
     for item in nodes[1:]:
         new_types = _ExprAnalyser().get_possible_types_from_node(item)
 
-        common = [i for i in common_types if _is_type_in_list(i, new_types)]
-
-        rejected = [i for i in common_types if i not in common]
-        common += [i for i in new_types if _is_type_in_list(i, rejected)]
-
-        common_types = common
+        tmp = []
+        for c in common_types:
+            for t in new_types:
+                if t.compare_type(c) or c.compare_type(t):
+                    tmp.append(c)
+                    break
+
+        common_types = tmp
 
     if filter_fn is not None:
         common_types = [i for i in common_types if filter_fn(i)]