diff --git a/artiq/py2llvm/builtins.py b/artiq/py2llvm/builtins.py
index 569b85cb2..48621ce10 100644
--- a/artiq/py2llvm/builtins.py
+++ b/artiq/py2llvm/builtins.py
@@ -44,7 +44,7 @@ def is_int(typ, width=None):
 
 def get_int_width(typ):
     if is_int(typ):
-        return types.get_value(typ["width"])
+        return types.get_value(typ.find()["width"])
 
 def is_float(typ):
     return types.is_mono(typ, "float")
diff --git a/artiq/py2llvm/typing.py b/artiq/py2llvm/typing.py
index 5e2c498fc..5d2b140a9 100644
--- a/artiq/py2llvm/typing.py
+++ b/artiq/py2llvm/typing.py
@@ -273,6 +273,22 @@ class ASTTypedRewriter(algorithm.Transformer):
                                if_loc=node.if_loc, else_loc=node.else_loc, loc=node.loc)
         return self.visit(node)
 
+    def visit_ListComp(self, node):
+        extractor = LocalExtractor(env_stack=self.env_stack, engine=self.engine)
+        extractor.visit(node)
+
+        node = asttyped.ListCompT(
+            typing_env=extractor.typing_env, globals_in_scope=extractor.global_,
+            type=types.TVar(),
+            elt=node.elt, generators=node.generators,
+            begin_loc=node.begin_loc, end_loc=node.end_loc, loc=node.loc)
+
+        try:
+            self.env_stack.append(node.typing_env)
+            return self.generic_visit(node)
+        finally:
+            self.env_stack.pop()
+
     def visit_Raise(self, node):
         node = self.generic_visit(node)
         if node.cause:
@@ -297,7 +313,6 @@ class ASTTypedRewriter(algorithm.Transformer):
     visit_Ellipsis = visit_unsupported
     visit_GeneratorExp = visit_unsupported
     visit_Lambda = visit_unsupported
-    visit_ListComp = visit_unsupported
     visit_Set = visit_unsupported
     visit_SetComp = visit_unsupported
     visit_Str = visit_unsupported
@@ -646,6 +661,14 @@ class Inferencer(algorithm.Visitor):
                         [self._coerce_one(typ, operand, other_node) for operand in operands]
         node.type.unify(builtins.TBool())
 
+    def visit_ListCompT(self, node):
+        self.generic_visit(node)
+        node.type.unify(builtins.TList(node.elt.type)) # should never fail
+
+    def visit_comprehension(self, node):
+        self.generic_visit(node)
+        self._unify_collection(element=node.target, collection=node.iter)
+
     def visit_Assign(self, node):
         self.generic_visit(node)
         if len(node.targets) > 1:
diff --git a/lit-test/py2llvm/typing/unify.py b/lit-test/py2llvm/typing/unify.py
index 64dfb20b7..94207cc1f 100644
--- a/lit-test/py2llvm/typing/unify.py
+++ b/lit-test/py2llvm/typing/unify.py
@@ -47,3 +47,6 @@ True and False
 
 not 1
 # CHECK-L: 1:int(width='i):bool
+
+[x for x in [1]]
+# CHECK-L: [x:int(width='j) for x:int(width='j) in [1:int(width='j)]:list(elt=int(width='j))]:list(elt=int(width='j))