diff --git a/phasm/type3/constraintsgenerator.py b/phasm/type3/constraintsgenerator.py
index 217bec3..ba95a86 100644
--- a/phasm/type3/constraintsgenerator.py
+++ b/phasm/type3/constraintsgenerator.py
@@ -115,7 +115,7 @@ def expression(ctx: Context, inp: ourlang.Expression) -> ConstraintGenerator:
     if isinstance(inp, ourlang.AccessStructMember):
         assert isinstance(inp.struct_type3, type3types.Type3)  # When does this happen?
         st_args = prelude.struct.did_construct(inp.struct_type3)
-        assert st_args is not None  # When does this happen?
+        assert st_args is not None  # FIXME: See test_struct.py::test_struct_not_accessible
 
         yield from expression(ctx, inp.varref)
         yield SameTypeConstraint(st_args[inp.member], inp.type3,
diff --git a/tests/integration/test_lang/test_struct.py b/tests/integration/test_lang/test_struct.py
index 98020c6..bf9f2b2 100644
--- a/tests/integration/test_lang/test_struct.py
+++ b/tests/integration/test_lang/test_struct.py
@@ -100,3 +100,15 @@ class f32:
 
     with pytest.raises(StaticError, match='f32 already defined as type'):
         Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+@pytest.mark.skip(reason='FIXME: See constraintgenerator.py for AccessStructMember')
+def test_struct_not_accessible():
+    code_py = """
+@exported
+def testEntry(x: u8) -> u8:
+    return x.y
+"""
+
+    with pytest.raises(Type3Exception, match='u8 is not struct'):
+        Suite(code_py).run_code()