diff --git a/artiq/compiler/module.py b/artiq/compiler/module.py
index d5d21391b..2b847eb27 100644
--- a/artiq/compiler/module.py
+++ b/artiq/compiler/module.py
@@ -15,6 +15,7 @@ class Module:
         inferencer = transforms.Inferencer(engine=engine)
         int_monomorphizer = transforms.IntMonomorphizer(engine=engine)
         monomorphism_validator = validators.MonomorphismValidator(engine=engine)
+        escape_validator = validators.EscapeValidator(engine=engine)
 
         parsetree, comments = parse_buffer(source_buffer, engine=engine)
         typedtree = asttyped_rewriter.visit(parsetree)
@@ -22,6 +23,7 @@ class Module:
         int_monomorphizer.visit(typedtree)
         inferencer.visit(typedtree)
         monomorphism_validator.visit(typedtree)
+        escape_validator.visit(typedtree)
 
         self.name = os.path.basename(source_buffer.name)
         self.globals = asttyped_rewriter.globals
diff --git a/artiq/compiler/types.py b/artiq/compiler/types.py
index 47d6f055b..7e8c611f6 100644
--- a/artiq/compiler/types.py
+++ b/artiq/compiler/types.py
@@ -82,8 +82,8 @@ class TMono(Type):
 
     attributes = {}
 
-    def __init__(self, name, params={}, region=None):
-        self.name, self.params, self.region = name, params, region
+    def __init__(self, name, params={}):
+        self.name, self.params = name, params
 
     def find(self):
         return self
@@ -125,7 +125,6 @@ class TTuple(Type):
     """
 
     attributes = {}
-    region = None
 
     def __init__(self, elts=[]):
         self.elts = elts
@@ -171,8 +170,8 @@ class TFunction(Type):
 
     attributes = {}
 
-    def __init__(self, args, optargs, ret, region=None):
-        self.args, self.optargs, self.ret, self.region = args, optargs, ret, region
+    def __init__(self, args, optargs, ret):
+        self.args, self.optargs, self.ret = args, optargs, ret
 
     def arity(self):
         return len(self.args) + len(self.optargs)
@@ -219,8 +218,6 @@ class TBuiltin(Type):
     type is treated specially according to its name.
     """
 
-    region = None
-
     def __init__(self, name):
         self.name = name
         self.attributes = {}
diff --git a/artiq/compiler/validators/escape.py b/artiq/compiler/validators/escape.py
new file mode 100644
index 000000000..4f02b1b7c
--- /dev/null
+++ b/artiq/compiler/validators/escape.py
@@ -0,0 +1,10 @@
+"""
+:class:`EscapeValidator` verifies that no mutable data escapes
+the region of its allocation.
+"""
+
+from pythonparser import algorithm, diagnostic
+from .. import asttyped, types, builtins
+
+class EscapeValidator(algorithm.Visitor):
+    pass