https://github.com/python/cpython/commit/85f727c5fb2afa60affa9ae3396ce4149cf5215d
commit: 85f727c5fb2afa60affa9ae3396ce4149cf5215d
branch: main
author: Jelle Zijlstra <[email protected]>
committer: JelleZijlstra <[email protected]>
date: 2024-04-22T12:50:26-07:00
summary:
gh-109118: Allow lambdas in annotation scopes in classes (#118019)
files:
A Misc/NEWS.d/next/Core and
Builtins/2024-04-17-17-52-32.gh-issue-109118.q9iPEI.rst
M Doc/whatsnew/3.13.rst
M Lib/test/test_type_params.py
M Python/symtable.c
diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst
index c04dc924d1efa5..67d1956a19697e 100644
--- a/Doc/whatsnew/3.13.rst
+++ b/Doc/whatsnew/3.13.rst
@@ -241,6 +241,9 @@ Other Language Changes
ones if configured to do so.
(Contributed by Pedro Sousa Lacerda in :gh:`66449`.)
+* :ref:`annotation scope <annotation-scopes>` within class scopes can now
+ contain lambdas. (Contributed by Jelle Zijlstra in :gh:`109118`.)
+
New Modules
===========
diff --git a/Lib/test/test_type_params.py b/Lib/test/test_type_params.py
index 25ee188731f31f..fbb80d9aac9942 100644
--- a/Lib/test/test_type_params.py
+++ b/Lib/test/test_type_params.py
@@ -486,8 +486,6 @@ class C[T]:
{}
"""
error_cases = [
- "type Alias1[T] = lambda: T",
- "type Alias2 = lambda: T",
"type Alias3[T] = (T for _ in (1,))",
"type Alias4 = (T for _ in (1,))",
"type Alias5[T] = [T for _ in (1,)]",
@@ -499,6 +497,54 @@ class C[T]:
r"Cannot use [a-z]+ in annotation
scope within class scope"):
run_code(code.format(case))
+ def test_lambda_in_alias_in_class(self):
+ code = """
+ T = "global"
+ class C:
+ T = "class"
+ type Alias = lambda: T
+ """
+ C = run_code(code)["C"]
+ self.assertEqual(C.Alias.__value__(), "global")
+
+ def test_lambda_in_alias_in_generic_class(self):
+ code = """
+ class C[T]:
+ T = "class"
+ type Alias = lambda: T
+ """
+ C = run_code(code)["C"]
+ self.assertIs(C.Alias.__value__(), C.__type_params__[0])
+
+ def test_lambda_in_generic_alias_in_class(self):
+ # A lambda nested in the alias cannot see the class scope, but can see
+ # a surrounding annotation scope.
+ code = """
+ T = U = "global"
+ class C:
+ T = "class"
+ U = "class"
+ type Alias[T] = lambda: (T, U)
+ """
+ C = run_code(code)["C"]
+ T, U = C.Alias.__value__()
+ self.assertIs(T, C.Alias.__type_params__[0])
+ self.assertEqual(U, "global")
+
+ def test_lambda_in_generic_alias_in_generic_class(self):
+ # A lambda nested in the alias cannot see the class scope, but can see
+ # a surrounding annotation scope.
+ code = """
+ class C[T, U]:
+ T = "class"
+ U = "class"
+ type Alias[T] = lambda: (T, U)
+ """
+ C = run_code(code)["C"]
+ T, U = C.Alias.__value__()
+ self.assertIs(T, C.Alias.__type_params__[0])
+ self.assertIs(U, C.__type_params__[1])
+
def make_base(arg):
class Base:
diff --git a/Misc/NEWS.d/next/Core and
Builtins/2024-04-17-17-52-32.gh-issue-109118.q9iPEI.rst b/Misc/NEWS.d/next/Core
and Builtins/2024-04-17-17-52-32.gh-issue-109118.q9iPEI.rst
new file mode 100644
index 00000000000000..124540045547b1
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and
Builtins/2024-04-17-17-52-32.gh-issue-109118.q9iPEI.rst
@@ -0,0 +1,2 @@
+:ref:`annotation scope <annotation-scopes>` within class scopes can now
+contain lambdas.
diff --git a/Python/symtable.c b/Python/symtable.c
index 36ccc0e73723d5..483ef1c3c46542 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -2140,17 +2140,6 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
VISIT(st, expr, e->v.UnaryOp.operand);
break;
case Lambda_kind: {
- if (st->st_cur->ste_can_see_class_scope) {
- // gh-109118
- PyErr_Format(PyExc_SyntaxError,
- "Cannot use lambda in annotation scope within class
scope");
- PyErr_RangedSyntaxLocationObject(st->st_filename,
- e->lineno,
- e->col_offset + 1,
- e->end_lineno,
- e->end_col_offset + 1);
- VISIT_QUIT(st, 0);
- }
if (e->v.Lambda.args->defaults)
VISIT_SEQ(st, expr, e->v.Lambda.args->defaults);
if (e->v.Lambda.args->kw_defaults)
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