diff --git a/artiq/py2llvm/types.py b/artiq/py2llvm/types.py
index 078051883..60768a349 100644
--- a/artiq/py2llvm/types.py
+++ b/artiq/py2llvm/types.py
@@ -180,6 +180,18 @@ def TList(elt=None):
     return TMono("list", {"elt": elt})
 
 
+def is_var(typ):
+    return isinstance(typ, TVar)
+
+def is_mono(typ, name, **params):
+    return isinstance(typ, TMono) and \
+        typ.name == name and typ.params == params
+
+def is_numeric(typ):
+    return isinstance(typ, TMono) and \
+        typ.name in ('int', 'float')
+
+
 class TypePrinter(object):
     """
     A class that prints types using Python-like syntax and gives
diff --git a/artiq/py2llvm/typing.py b/artiq/py2llvm/typing.py
index 2fc33fc9d..943b5b6fe 100644
--- a/artiq/py2llvm/typing.py
+++ b/artiq/py2llvm/typing.py
@@ -284,6 +284,27 @@ class Inferencer(algorithm.Transformer):
                                 op_locs=node.op_locs, loc=node.loc)
         return self.visit(node)
 
+    def visit_UnaryOp(self, node):
+        node = self.generic_visit(node)
+        node = asttyped.UnaryOpT(type=types.TVar(),
+                                 op=node.op, operand=node.operand,
+                                 loc=node.loc)
+        return self.visit(node)
+
+    def visit_BinOp(self, node):
+        node = self.generic_visit(node)
+        node = asttyped.BinOpT(type=types.TVar(),
+                               left=node.left, op=node.op, right=node.right,
+                               loc=node.loc)
+        return self.visit(node)
+
+    def visit_Compare(self, node):
+        node = self.generic_visit(node)
+        node = asttyped.CompareT(type=types.TVar(),
+                                 left=node.left, ops=node.ops, comparators=node.comparators,
+                                 loc=node.loc)
+        return self.visit(node)
+
     # Visitors that just unify types
     #
     def visit_ListT(self, node):
@@ -310,6 +331,21 @@ class Inferencer(algorithm.Transformer):
                         node.loc, value.loc, self._makenotes_elts(node.values, "an operand"))
         return node
 
+    def visit_UnaryOpT(self, node):
+        if isinstance(node.op, ast.Not):
+            node.type = types.TBool()
+        else:
+            operand_type = node.operand.type.find()
+            if types.is_numeric(operand_type):
+                node.type = operand_type
+            elif not types.is_var(operand_type):
+                diag = diagnostic.Diagnostic("error",
+                    "expected operand to be of numeric type, not {type}",
+                    {"type": types.TypePrinter().name(operand_type)},
+                    node.operand.loc)
+                self.engine.process(diag)
+        return node
+
     def visit_Assign(self, node):
         node = self.generic_visit(node)
         if len(node.targets) > 1:
@@ -375,7 +411,6 @@ class Inferencer(algorithm.Transformer):
     visit_SetComp = visit_unsupported
     visit_Str = visit_unsupported
     visit_Starred = visit_unsupported
-    visit_UnaryOp = visit_unsupported
     visit_Yield = visit_unsupported
     visit_YieldFrom = visit_unsupported
 
diff --git a/lit-test/py2llvm/typing/error_unify.py b/lit-test/py2llvm/typing/error_unify.py
index 1140ba61f..8f0faf23a 100644
--- a/lit-test/py2llvm/typing/error_unify.py
+++ b/lit-test/py2llvm/typing/error_unify.py
@@ -16,3 +16,6 @@ a = b
 1 and False
 # CHECK-L: note: an operand of type int(width='a)
 # CHECK-L: note: an operand of type bool
+
+# CHECK-L: ${LINE:+1}: error: expected operand to be of numeric type, not list(elt='a)
+~[]
diff --git a/lit-test/py2llvm/typing/unify.py b/lit-test/py2llvm/typing/unify.py
index 8ea23dd0e..64dfb20b7 100644
--- a/lit-test/py2llvm/typing/unify.py
+++ b/lit-test/py2llvm/typing/unify.py
@@ -41,3 +41,9 @@ True and False
 
 1 and 0
 # CHECK-L: 1:int(width='g) and 0:int(width='g):int(width='g)
+
+~1
+# CHECK-L: 1:int(width='h):int(width='h)
+
+not 1
+# CHECK-L: 1:int(width='i):bool