Support PEP 695 type parameters on class definitions and type aliases

CHANGELOG.md

@@ -8,6 +8,7 @@
 - #623, #819, #863 Support MatchOr, MatchSequence, MatchStar (@jheld, @lieryan)
 - #870 Add default implementation for is_dir() (@lieryan)
 - #872 Fix unicode handling in patchedast (@lieryan)
+- #845 Support PEP 695 type parameters on class definitions and type aliases in patchedast (@marlon-costa-dc)
 
 # Release 1.14.0
 

rope/refactor/patchedast.py

@@ -327,6 +327,7 @@ def _ClassDef(self, node):
         for decorator in node.decorator_list:
             children.extend(("@", decorator))
         children.extend(["class", node.name])
+        self._add_type_params(node, children)
         if node.bases:
             children.append("(")
             children.extend(self._child_nodes(node.bases, ","))
@@ -493,9 +494,7 @@ def _handle_function_def_node(self, node, is_async):
             children.extend(("@", decorator))
         children.extend(["async", "def"] if is_async else ["def"])
         children.append(node.name)
-        type_params = getattr(node, "type_params", [])
-        if type_params:
-            children.extend(["[", *self._child_nodes(type_params, ","), "]"])
+        self._add_type_params(node, children)
         children.extend(["(", node.args, ")"])
         children.append(":")
         children.extend(node.body)
@@ -872,9 +871,17 @@ def _MatchMapping(self, node):
         self._handle(node, children)
 
     def _TypeAlias(self, node):
-        children = ["type", node.name, node.value]
+        children = ["type", node.name]
+        self._add_type_params(node, children)
+        children.append(node.value)
         self._handle(node, children)
 
+    def _add_type_params(self, node, children):
+        """Append the PEP 695 ``[T, ...]`` clause of a def, class or type alias."""
+        type_params = getattr(node, "type_params", [])
+        if type_params:
+            children.extend(["[", *self._child_nodes(type_params, ","), "]"])
+
     def _TypeVar(self, node):
         children = [node.name]
         if node.bound:

ropetest/refactor/patchedasttest.py

@@ -326,6 +326,83 @@ def test_handling_format_strings_basic(self):
         checker.check_children("JoinedStr", ['f"', "abc", "FormattedValue", "", '"'])
         checker.check_children("FormattedValue", ["{", "", "Name", "", "}"])
 
+    @testutils.only_for_versions_higher("3.12")
+    def test_handling_pep695_type_alias(self):
+        source = dedent("""\
+            type Alias[T] = list[T]
+        """)
+        ast_frag = patchedast.get_patched_ast(source, True)
+        checker = _ResultChecker(self, ast_frag)
+        checker.check_children(
+            "TypeAlias",
+            ["type", " ", "Name", "", "[", "", "TypeVar", "", "]", " = ",
+             "Subscript"],
+        )
+
+    @testutils.only_for_versions_higher("3.12")
+    def test_handling_pep695_generic_function(self):
+        # TP occurs only in the type parameter list, so its region can only
+        # come from the "[TP]" clause rendered between the name and "(".
+        source = dedent("""\
+            def f[TP](x):
+                return x
+        """)
+        ast_frag = patchedast.get_patched_ast(source, True)
+        checker = _ResultChecker(self, ast_frag)
+        checker.check_children(
+            "FunctionDef",
+            ["def", " ", "f", "", "[", "", "TypeVar", "", "]", "", "(", "",
+             "arguments", "", ")", "", ":", "\n    ", "Return"],
+        )
+        start = source.index("TP")
+        checker.check_region("TypeVar", start, start + len("TP"))
+
+    @testutils.only_for_versions_higher("3.12")
+    def test_handling_pep695_generic_class(self):
+        source = dedent("""\
+            class C[TP]:
+                pass
+        """)
+        ast_frag = patchedast.get_patched_ast(source, True)
+        checker = _ResultChecker(self, ast_frag)
+        checker.check_children(
+            "ClassDef",
+            ["class", " ", "C", "", "[", "", "TypeVar", "", "]", "", ":",
+             "\n    ", "Pass"],
+        )
+        start = source.index("TP")
+        checker.check_region("TypeVar", start, start + len("TP"))
+
+    @testutils.only_for_versions_higher("3.10")
+    def test_handling_match_sequence_and_star(self):
+        source = dedent("""\
+            match x:
+                case [1, *rest]:
+                    pass
+        """)
+        ast_frag = patchedast.get_patched_ast(source, True)
+        checker = _ResultChecker(self, ast_frag)
+        checker.check_children(
+            "MatchSequence",
+            ["[", "", "MatchValue", "", ",", " ", "MatchStar", "", "]"],
+        )
+        start = source.index("[1, *rest]")
+        checker.check_region("MatchSequence", start, start + len("[1, *rest]"))
+        checker.check_children("MatchStar", ["*", "", "rest"])
+
+    @testutils.only_for_versions_higher("3.10")
+    def test_handling_match_or_and_singleton(self):
+        source = dedent("""\
+            match x:
+                case 1 | None:
+                    pass
+        """)
+        ast_frag = patchedast.get_patched_ast(source, True)
+        checker = _ResultChecker(self, ast_frag)
+        checker.check_children(
+            "MatchOr", ["MatchValue", " ", "|", " ", "MatchSingleton"]
+        )
+
     @testutils.only_for_versions_higher("3.6")
     def test_handling_format_strings_with_implicit_join(self):
         source = '''"1" + rf'abc{a}' f"""xxx{b} """\n'''