Add name lookup

mypy/semanal.py

@@ -1956,13 +1956,13 @@ class Foo(Bar, Generic[T]): ...
         for name, tvar_expr in declared_tvars:
             tvar_expr_default = tvar_expr.default
             if isinstance(tvar_expr_default, UnboundType):
-                # Assumption here is that the names cannot be duplicated
                 # TODO: - detect out of order and self-referencing TypeVars
                 #       - nested default types, e.g. list[T1]
-                for fullname, type_var in self.tvar_scope.scope.items():
-                    type_var_name = fullname.rpartition(".")[2]
-                    if tvar_expr_default.name == type_var_name:
-                        tvar_expr.default = type_var
+                n = self.lookup_qualified(
+                    tvar_expr_default.name, tvar_expr_default, suppress_errors=True
+                )
+                if n is not None and (default := self.tvar_scope.get_binding(n)) is not None:
+                    tvar_expr.default = default
             tvar_def = self.tvar_scope.bind_new(name, tvar_expr)
             tvar_defs.append(tvar_def)
         return base_type_exprs, tvar_defs, is_protocol

test-data/unit/check-typevar-defaults.test

@@ -397,6 +397,36 @@ def func_d2(
     n = ClassD2[int, float, str]()
     reveal_type(n)  # N: Revealed type is "__main__.ClassD2[builtins.int, builtins.float, builtins.str]"
 
+[case testTypeVarDefaultsClassRecursiveMultipleFiles]
+# flags: --disallow-any-generics
+from typing import Generic, TypeVar
+from file2 import T as T2
+
+T = TypeVar('T', default=T2)
+
+class ClassG1(Generic[T2, T]):
+    pass
+
+def func(
+    a: ClassG1,
+    b: ClassG1[str],
+    c: ClassG1[str, float],
+) -> None:
+    reveal_type(a)  # N: Revealed type is "__main__.ClassG1[builtins.int, builtins.int]"
+    reveal_type(b)  # N: Revealed type is "__main__.ClassG1[builtins.str, builtins.str]"
+    reveal_type(c)  # N: Revealed type is "__main__.ClassG1[builtins.str, builtins.float]"
+
+    k = ClassG1()
+    reveal_type(k)  # N: Revealed type is "__main__.ClassG1[builtins.int, builtins.int]"
+    l = ClassG1[str]()
+    reveal_type(l)  # N: Revealed type is "__main__.ClassG1[builtins.str, builtins.str]"
+    m = ClassG1[str, float]()
+    reveal_type(m)  # N: Revealed type is "__main__.ClassG1[builtins.str, builtins.float]"
+
+[file file2.py]
+from typing import TypeVar
+T = TypeVar('T', default=int)
+
 [case testTypeVarDefaultsTypeAlias1]
 # flags: --disallow-any-generics
 from typing import Any, Dict, List, Tuple, TypeVar, Union