diff --git a/artiq/compiler/embedding.py b/artiq/compiler/embedding.py
index f695029cf..d1b276766 100644
--- a/artiq/compiler/embedding.py
+++ b/artiq/compiler/embedding.py
@@ -52,7 +52,14 @@ class EmbeddingMap:
         self.object_forward_map = {}
         self.object_reverse_map = {}
         self.module_map = {}
+
+        # type_map connects the host Python `type` to the pair of associated
+        # `(TInstance, TConstructor)`s. The `used_…_names` sets cache the
+        # respective `.name`s for O(1) collision avoidance.
         self.type_map = {}
+        self.used_instance_type_names = set()
+        self.used_constructor_type_names = set()
+
         self.function_map = {}
         self.str_forward_map = {}
         self.str_reverse_map = {}
@@ -98,16 +105,6 @@ class EmbeddingMap:
 
     # Types
     def store_type(self, host_type, instance_type, constructor_type):
-        self._rename_type(instance_type)
-        self.type_map[host_type] = (instance_type, constructor_type)
-
-    def retrieve_type(self, host_type):
-        return self.type_map[host_type]
-
-    def has_type(self, host_type):
-        return host_type in self.type_map
-
-    def _rename_type(self, new_instance_type):
         # Generally, user-defined types that have exact same name (which is to say, classes
         # defined inside functions) do not pose a problem to the compiler. The two places which
         # cannot handle this are:
@@ -116,12 +113,29 @@ class EmbeddingMap:
         # Since handling #2 requires renaming on ARTIQ side anyway, it's more straightforward
         # to do it once when embedding (since non-embedded code cannot define classes in
         # functions). Also, easier to debug.
-        n = 0
-        for host_type in self.type_map:
-            instance_type, constructor_type = self.type_map[host_type]
-            if instance_type.name == new_instance_type.name:
-                n += 1
-                new_instance_type.name = "{}.{}".format(new_instance_type.name, n)
+        suffix = 0
+        new_instance_name = instance_type.name
+        new_constructor_name = constructor_type.name
+        while True:
+            if (new_instance_name not in self.used_instance_type_names
+                    and new_constructor_name not in self.used_constructor_type_names):
+                break
+            suffix += 1
+            new_instance_name = f"{instance_type.name}.{suffix}"
+            new_constructor_name = f"{constructor_type.name}.{suffix}"
+
+        self.used_instance_type_names.add(new_instance_name)
+        instance_type.name = new_instance_name
+        self.used_constructor_type_names.add(new_constructor_name)
+        constructor_type.name = new_constructor_name
+
+        self.type_map[host_type] = (instance_type, constructor_type)
+
+    def retrieve_type(self, host_type):
+        return self.type_map[host_type]
+
+    def has_type(self, host_type):
+        return host_type in self.type_map
 
     def attribute_count(self):
         count = 0
diff --git a/artiq/test/lit/embedding/class_same_name.py b/artiq/test/lit/embedding/class_same_name.py
new file mode 100644
index 000000000..46cf7c16d
--- /dev/null
+++ b/artiq/test/lit/embedding/class_same_name.py
@@ -0,0 +1,51 @@
+# RUN: %python -m artiq.compiler.testbench.embedding %s
+
+from artiq.language.core import *
+
+
+class InnerA:
+    def __init__(self, val):
+        self.val = val
+
+    @kernel
+    def run_once(self):
+        return self.val
+
+
+class InnerB:
+    def __init__(self, val):
+        self.val = val
+
+    @kernel
+    def run_once(self):
+        return self.val
+
+
+def make_runner(InnerCls, val):
+    class Runner:
+        def __init__(self):
+            self.inner = InnerCls(val)
+
+        @kernel
+        def run_once(self):
+            return self.inner.run_once()
+
+    return Runner()
+
+
+class Parent:
+    def __init__(self):
+        self.a = make_runner(InnerA, 1)
+        self.b = make_runner(InnerB, 42.0)
+
+    @kernel
+    def run_once(self):
+        return self.a.run_once() + self.b.run_once()
+
+
+parent = Parent()
+
+
+@kernel
+def entrypoint():
+    parent.run_once()