From fa74c3e05044d227ba47a949a755eee99031c21d Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Thu, 4 Jun 2026 14:52:41 +0300
Subject: [PATCH] gh-82312: Further improvement of error messages for
 generating AST nodes

This is a follow up of GH-17715.

* Use %T instead of _PyType_Name().
* Add the wrong type name we got for identifier and string.
---
 Lib/test/test_ast/test_ast.py |  11 ++-
 Parser/asdl_c.py              |  19 ++--
 Python/Python-ast.c           | 175 +++++++++++++++++-----------------
 3 files changed, 105 insertions(+), 100 deletions(-)

diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py
index fd3b33bab7f833..31e218df127ae6 100644
--- a/Lib/test/test_ast/test_ast.py
+++ b/Lib/test/test_ast/test_ast.py
@@ -1098,10 +1098,17 @@ def test_required_field_messages(self):
         ):
             compile(expr_with_wrong_body, "<test>", "eval")
 
+        variable = ast.parse("test", mode="eval")
+        variable.body.id = b'test'
+        with self.assertRaisesRegex(TypeError,
+            "field 'id' was expecting a string object, got bytes"
+        ):
+            compile(variable, "<test>", "eval")
+
         constant = ast.parse("u'test'", mode="eval")
         constant.body.kind = 0xFF
-        with self.assertRaisesRegex(
-            TypeError, "field 'kind' was expecting a string or bytes object"
+        with self.assertRaisesRegex(TypeError,
+            "field 'kind' was expecting a string or bytes object, got int"
         ):
             compile(constant, "<test>", "eval")
 
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index e2a57177d20afb..d53886866f54f8 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -554,8 +554,8 @@ def typeCheck(self, name):
         self.emit("return 1;", 2)
         self.emit("}", 1)
         self.emit("if (!isinstance && field != NULL) {", 1)
-        error = "field '%%s' was expecting node of type '%s', got '%%s'" % name
-        self.emit("PyErr_Format(PyExc_TypeError, \"%s\", field, _PyType_Name(Py_TYPE(obj)));" % error, 2, reflow=False)
+        error = "field '%%s' was expecting node of type '%s', got '%%T'" % name
+        self.emit("PyErr_Format(PyExc_TypeError, \"%s\", field, obj);" % error, 2, reflow=False)
         self.emit("return 1;", 2)
         self.emit("}", 1)
 
@@ -692,7 +692,7 @@ def visitField(self, field, name, sum=None, prod=None, depth=0):
             self.emit("Py_ssize_t i;", depth+1)
             self.emit("if (!PyList_Check(tmp)) {", depth+1)
             self.emit("PyErr_Format(PyExc_TypeError, \"%s field \\\"%s\\\" must "
-                      "be a list, not a %%.200s\", _PyType_Name(Py_TYPE(tmp)));" %
+                      "be a list, not a %%T\", tmp);" %
                       (name, field.name),
                       depth+2, reflow=False)
             self.emit("goto failed;", depth+2)
@@ -991,10 +991,9 @@ def visitModule(self, mod):
 
     res = 0; /* if no error occurs, this stays 0 to the end */
     if (numfields < PyTuple_GET_SIZE(args)) {
-        PyErr_Format(PyExc_TypeError, "%.400s constructor takes at most "
+        PyErr_Format(PyExc_TypeError, "%T constructor takes at most "
                      "%zd positional argument%s",
-                     _PyType_Name(Py_TYPE(self)),
-                     numfields, numfields == 1 ? "" : "s");
+                     self, numfields, numfields == 1 ? "" : "s");
         res = -1;
         goto cleanup;
     }
@@ -1748,7 +1747,7 @@ def visitModule(self, mod):
 static int obj2ast_identifier(struct ast_state *state, PyObject* obj, PyObject** out, const char* field, PyArena* arena)
 {
     if (!PyUnicode_CheckExact(obj) && obj != Py_None) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string object", field);
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string object, got %T", field, obj);
         return -1;
     }
     return obj2ast_object(state, obj, out, field, arena);
@@ -1757,7 +1756,7 @@ def visitModule(self, mod):
 static int obj2ast_string(struct ast_state *state, PyObject* obj, PyObject** out, const char* field, PyArena* arena)
 {
     if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string or bytes object", field);
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string or bytes object, got %T", field, obj);
         return -1;
     }
     return obj2ast_object(state, obj, out, field, arena);
@@ -2144,8 +2143,8 @@ class PartingShots(StaticVisitor):
         return -1;
     }
     if (!isinstance) {
-        PyErr_Format(PyExc_TypeError, "expected %s node, got %.400s",
-                     req_name[mode], _PyType_Name(Py_TYPE(ast)));
+        PyErr_Format(PyExc_TypeError, "expected %s node, got %T",
+                     req_name[mode], ast);
         return -1;
     }
     return 0;
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 49b6bf1d12b6fa..f36072dfce098c 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -5303,10 +5303,9 @@ ast_type_init(PyObject *self, PyObject *args, PyObject *kw)
 
     res = 0; /* if no error occurs, this stays 0 to the end */
     if (numfields < PyTuple_GET_SIZE(args)) {
-        PyErr_Format(PyExc_TypeError, "%.400s constructor takes at most "
+        PyErr_Format(PyExc_TypeError, "%T constructor takes at most "
                      "%zd positional argument%s",
-                     _PyType_Name(Py_TYPE(self)),
-                     numfields, numfields == 1 ? "" : "s");
+                     self, numfields, numfields == 1 ? "" : "s");
         res = -1;
         goto cleanup;
     }
@@ -6060,7 +6059,7 @@ static int obj2ast_constant(struct ast_state *Py_UNUSED(state), PyObject* obj,
 static int obj2ast_identifier(struct ast_state *state, PyObject* obj, PyObject** out, const char* field, PyArena* arena)
 {
     if (!PyUnicode_CheckExact(obj) && obj != Py_None) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string object", field);
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string object, got %T", field, obj);
         return -1;
     }
     return obj2ast_object(state, obj, out, field, arena);
@@ -6069,7 +6068,7 @@ static int obj2ast_identifier(struct ast_state *state, PyObject* obj, PyObject**
 static int obj2ast_string(struct ast_state *state, PyObject* obj, PyObject** out, const char* field, PyArena* arena)
 {
     if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string or bytes object", field);
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting a string or bytes object, got %T", field, obj);
         return -1;
     }
     return obj2ast_object(state, obj, out, field, arena);
@@ -10886,7 +10885,7 @@ obj2ast_mod(struct ast_state *state, PyObject* obj, mod_ty* out, const char*
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'mod', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'mod', got '%T'", field, obj);
         return 1;
     }
     tp = state->Module_type;
@@ -10912,7 +10911,7 @@ obj2ast_mod(struct ast_state *state, PyObject* obj, mod_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Module field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Module field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -10950,7 +10949,7 @@ obj2ast_mod(struct ast_state *state, PyObject* obj, mod_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Module field \"type_ignores\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Module field \"type_ignores\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11000,7 +10999,7 @@ obj2ast_mod(struct ast_state *state, PyObject* obj, mod_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Interactive field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Interactive field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11080,7 +11079,7 @@ obj2ast_mod(struct ast_state *state, PyObject* obj, mod_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "FunctionType field \"argtypes\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "FunctionType field \"argtypes\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11155,7 +11154,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'stmt', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'stmt', got '%T'", field, obj);
         return 1;
     }
     if (PyObject_GetOptionalAttr(obj, state->lineno, &tmp) < 0) {
@@ -11288,7 +11287,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "FunctionDef field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "FunctionDef field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11326,7 +11325,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "FunctionDef field \"decorator_list\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "FunctionDef field \"decorator_list\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11399,7 +11398,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "FunctionDef field \"type_params\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "FunctionDef field \"type_params\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11492,7 +11491,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11530,7 +11529,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"decorator_list\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"decorator_list\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11603,7 +11602,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"type_params\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncFunctionDef field \"type_params\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11678,7 +11677,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ClassDef field \"bases\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ClassDef field \"bases\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11716,7 +11715,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ClassDef field \"keywords\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ClassDef field \"keywords\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11754,7 +11753,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ClassDef field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ClassDef field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11792,7 +11791,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ClassDef field \"decorator_list\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ClassDef field \"decorator_list\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11830,7 +11829,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ClassDef field \"type_params\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ClassDef field \"type_params\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11912,7 +11911,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Delete field \"targets\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Delete field \"targets\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -11965,7 +11964,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Assign field \"targets\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Assign field \"targets\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12070,7 +12069,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TypeAlias field \"type_params\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TypeAlias field \"type_params\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12326,7 +12325,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "For field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "For field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12364,7 +12363,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "For field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "For field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12471,7 +12470,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncFor field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncFor field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12509,7 +12508,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncFor field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncFor field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12598,7 +12597,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "While field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "While field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12636,7 +12635,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "While field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "While field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12706,7 +12705,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "If field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "If field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12744,7 +12743,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "If field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "If field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12797,7 +12796,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "With field \"items\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "With field \"items\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12835,7 +12834,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "With field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "With field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12906,7 +12905,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncWith field \"items\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncWith field \"items\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -12944,7 +12943,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "AsyncWith field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "AsyncWith field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13031,7 +13030,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Match field \"cases\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Match field \"cases\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13133,7 +13132,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Try field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Try field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13171,7 +13170,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Try field \"handlers\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Try field \"handlers\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13209,7 +13208,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Try field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Try field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13247,7 +13246,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Try field \"finalbody\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Try field \"finalbody\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13301,7 +13300,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TryStar field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TryStar field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13339,7 +13338,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TryStar field \"handlers\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TryStar field \"handlers\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13377,7 +13376,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TryStar field \"orelse\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TryStar field \"orelse\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13415,7 +13414,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TryStar field \"finalbody\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TryStar field \"finalbody\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13515,7 +13514,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Import field \"names\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Import field \"names\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13603,7 +13602,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ImportFrom field \"names\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ImportFrom field \"names\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13688,7 +13687,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Global field \"names\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Global field \"names\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13739,7 +13738,7 @@ obj2ast_stmt(struct ast_state *state, PyObject* obj, stmt_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Nonlocal field \"names\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Nonlocal field \"names\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -13864,7 +13863,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'expr', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'expr', got '%T'", field, obj);
         return 1;
     }
     if (PyObject_GetOptionalAttr(obj, state->lineno, &tmp) < 0) {
@@ -13975,7 +13974,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "BoolOp field \"values\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "BoolOp field \"values\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14303,7 +14302,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Dict field \"keys\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Dict field \"keys\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14341,7 +14340,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Dict field \"values\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Dict field \"values\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14392,7 +14391,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Set field \"elts\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Set field \"elts\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14461,7 +14460,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ListComp field \"generators\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ListComp field \"generators\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14530,7 +14529,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "SetComp field \"generators\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "SetComp field \"generators\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14617,7 +14616,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "DictComp field \"generators\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "DictComp field \"generators\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14686,7 +14685,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "GeneratorExp field \"generators\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "GeneratorExp field \"generators\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14846,7 +14845,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Compare field \"ops\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Compare field \"ops\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14884,7 +14883,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Compare field \"comparators\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Compare field \"comparators\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14954,7 +14953,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Call field \"args\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Call field \"args\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -14992,7 +14991,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Call field \"keywords\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Call field \"keywords\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -15195,7 +15194,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "JoinedStr field \"values\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "JoinedStr field \"values\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -15246,7 +15245,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "TemplateStr field \"values\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "TemplateStr field \"values\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -15574,7 +15573,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "List field \"elts\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "List field \"elts\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -15643,7 +15642,7 @@ obj2ast_expr(struct ast_state *state, PyObject* obj, expr_ty* out, const char*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "Tuple field \"elts\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "Tuple field \"elts\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -16131,7 +16130,7 @@ obj2ast_comprehension(struct ast_state *state, PyObject* obj, comprehension_ty*
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "comprehension field \"ifs\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "comprehension field \"ifs\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -16203,7 +16202,7 @@ obj2ast_excepthandler(struct ast_state *state, PyObject* obj, excepthandler_ty*
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'excepthandler', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'excepthandler', got '%T'", field, obj);
         return 1;
     }
     if (PyObject_GetOptionalAttr(obj, state->lineno, &tmp) < 0) {
@@ -16332,7 +16331,7 @@ obj2ast_excepthandler(struct ast_state *state, PyObject* obj, excepthandler_ty*
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "ExceptHandler field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "ExceptHandler field \"body\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -16395,7 +16394,7 @@ obj2ast_arguments(struct ast_state *state, PyObject* obj, arguments_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "arguments field \"posonlyargs\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "arguments field \"posonlyargs\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -16433,7 +16432,7 @@ obj2ast_arguments(struct ast_state *state, PyObject* obj, arguments_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "arguments field \"args\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "arguments field \"args\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -16488,7 +16487,7 @@ obj2ast_arguments(struct ast_state *state, PyObject* obj, arguments_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "arguments field \"kwonlyargs\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "arguments field \"kwonlyargs\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -16526,7 +16525,7 @@ obj2ast_arguments(struct ast_state *state, PyObject* obj, arguments_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "arguments field \"kw_defaults\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "arguments field \"kw_defaults\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -16581,7 +16580,7 @@ obj2ast_arguments(struct ast_state *state, PyObject* obj, arguments_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "arguments field \"defaults\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "arguments field \"defaults\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -17108,7 +17107,7 @@ obj2ast_match_case(struct ast_state *state, PyObject* obj, match_case_ty* out,
         Py_ssize_t len;
         Py_ssize_t i;
         if (!PyList_Check(tmp)) {
-            PyErr_Format(PyExc_TypeError, "match_case field \"body\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+            PyErr_Format(PyExc_TypeError, "match_case field \"body\" must be a list, not a %T", tmp);
             goto failed;
         }
         len = PyList_GET_SIZE(tmp);
@@ -17163,7 +17162,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'pattern', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'pattern', got '%T'", field, obj);
         return 1;
     }
     if (PyObject_GetOptionalAttr(obj, state->lineno, &tmp) < 0) {
@@ -17316,7 +17315,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchSequence field \"patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchSequence field \"patterns\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17369,7 +17368,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchMapping field \"keys\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchMapping field \"keys\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17407,7 +17406,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchMapping field \"patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchMapping field \"patterns\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17495,7 +17494,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchClass field \"patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchClass field \"patterns\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17533,7 +17532,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchClass field \"kwd_attrs\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchClass field \"kwd_attrs\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17571,7 +17570,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchClass field \"kwd_patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchClass field \"kwd_patterns\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17701,7 +17700,7 @@ obj2ast_pattern(struct ast_state *state, PyObject* obj, pattern_ty* out, const
             Py_ssize_t len;
             Py_ssize_t i;
             if (!PyList_Check(tmp)) {
-                PyErr_Format(PyExc_TypeError, "MatchOr field \"patterns\" must be a list, not a %.200s", _PyType_Name(Py_TYPE(tmp)));
+                PyErr_Format(PyExc_TypeError, "MatchOr field \"patterns\" must be a list, not a %T", tmp);
                 goto failed;
             }
             len = PyList_GET_SIZE(tmp);
@@ -17756,7 +17755,7 @@ obj2ast_type_ignore(struct ast_state *state, PyObject* obj, type_ignore_ty*
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'type_ignore', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'type_ignore', got '%T'", field, obj);
         return 1;
     }
     tp = state->TypeIgnore_type;
@@ -17836,7 +17835,7 @@ obj2ast_type_param(struct ast_state *state, PyObject* obj, type_param_ty* out,
         return 1;
     }
     if (!isinstance && field != NULL) {
-        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'type_param', got '%s'", field, _PyType_Name(Py_TYPE(obj)));
+        PyErr_Format(PyExc_TypeError, "field '%s' was expecting node of type 'type_param', got '%T'", field, obj);
         return 1;
     }
     if (PyObject_GetOptionalAttr(obj, state->lineno, &tmp) < 0) {
@@ -18571,8 +18570,8 @@ int PyAst_CheckMode(PyObject *ast, int mode)
         return -1;
     }
     if (!isinstance) {
-        PyErr_Format(PyExc_TypeError, "expected %s node, got %.400s",
-                     req_name[mode], _PyType_Name(Py_TYPE(ast)));
+        PyErr_Format(PyExc_TypeError, "expected %s node, got %T",
+                     req_name[mode], ast);
         return -1;
     }
     return 0;