Correctly remove type variables from a union type

Author: theosotr

src/ir/typescript_types.py

@@ -489,9 +489,14 @@ def to_type_variable_free(self, factory):
         # type variable free.
         new_types = []
         for t in self.types:
-            new_types.append(t.to_type_variable_free(factory)
-                             if t.is_combound()
-                             else t)
+            if t.is_combound():
+                new_type = t.to_type_variable_free(factory)
+            elif t.is_type_var():
+                bound = t.get_bound_rec(factory)
+                new_type = factory.get_any_type() if bound is None else bound
+            else:
+                new_type = t
+            new_types.append(new_type)
         return UnionType(new_types)
 
     def unify_types(self, t1, factory, same_type=True):
@@ -787,7 +792,7 @@ def __init__(self, name="Array"):
             "T", variance=tp.Covariant)])
 
 
-class FunctionType(tp.TypeConstructor, ObjectType):
+class FunctionType(tp.TypeConstructor):
     def __init__(self, nr_type_parameters: int):
         name = "Function" + str(nr_type_parameters)
 
@@ -811,6 +816,7 @@ def __init__(self, nr_type_parameters: int):
 features of typescript.
 """
 
+
 def gen_type_alias_decl(gen,
                         etype=None) -> ts_ast.TypeAliasDeclaration:
     """ Generate a Type Declaration (Type Alias)
@@ -836,6 +842,7 @@ def gen_type_alias_decl(gen,
     gen._add_node_to_parent(gen.namespace, type_alias_decl)
     return type_alias_decl
 
+
 def add_type_alias(gen, namespace, type_name, ta_decl):
     gen.context._add_entity(namespace, 'types', type_name, ta_decl.get_type())
     gen.context._add_entity(namespace, 'decls', type_name, ta_decl)

tests/test_typescript.py

@@ -205,3 +205,17 @@ def test_union_type_unification2():
     assert (len(res) == 2 and
             res[t2.types[1]] == t1.types[4] and
             res[t2.types[2]] == t1.types[2])
+
+
+def test_union_to_type_variable_free():
+    type_param = tp.TypeParameter("S")
+    union = tst.UnionType([tst.NumberType(), type_param])
+
+    new_union = union.to_type_variable_free(tst.TypeScriptBuiltinFactory())
+    assert new_union == tst.UnionType([tst.NumberType(),
+                                       tst.TypeScriptBuiltinFactory().get_any_type()])
+
+    type_param = tp.TypeParameter("S", bound=tst.StringType())
+    union = tst.UnionType([tst.NumberType(), type_param])
+    new_union = union.to_type_variable_free(tst.TypeScriptBuiltinFactory())
+    assert new_union == tst.UnionType([tst.NumberType(), tst.StringType()])