change the type annotation error heuristic (#2583)

The previous one depended on the message from "typed_ast", which is
   not used anymore.

Instead, we check if there is a "# type:" substring in the source line
   of the exception. This can yield some false positives, but probably
   rarely.

Author: temyurchenko

astroid/builder.py

@@ -12,6 +12,7 @@
 
 import ast
 import os
+import re
 import textwrap
 import types
 import warnings
@@ -33,7 +34,6 @@
 # The comment used to select a statement to be extracted
 # when calling extract_node.
 _STATEMENT_SELECTOR = "#@"
-MISPLACED_TYPE_ANNOTATION_ERROR = "misplaced type annotation"
 
 if PY312_PLUS:
     warnings.filterwarnings("ignore", "invalid escape sequence", SyntaxWarning)
@@ -478,9 +478,11 @@ def _parse_string(
         )
     except SyntaxError as exc:
         # If the type annotations are misplaced for some reason, we do not want
-        # to fail the entire parsing of the file, so we need to retry the parsing without
-        # type comment support.
-        if exc.args[0] != MISPLACED_TYPE_ANNOTATION_ERROR or not type_comments:
+        # to fail the entire parsing of the file, so we need to retry the
+        # parsing without type comment support. We use a heuristic for
+        # determining if the error is due to type annotations.
+        type_annot_related = re.search(r"#\s+type:", exc.text or "")
+        if not (type_annot_related and type_comments):
             raise
 
         parser_module = get_parser_module(type_comments=False)

tests/test_builder.py

@@ -883,12 +883,6 @@ def test_module_build_dunder_file() -> None:
     assert module.path[0] == collections.__file__
 
 
-@pytest.mark.xfail(
-    reason=(
-        "The builtin ast module does not fail with a specific error "
-        "for syntax error caused by invalid type comments."
-    ),
-)
 def test_parse_module_with_invalid_type_comments_does_not_crash():
     node = builder.parse(
         """

tests/test_nodes.py

@@ -1304,6 +1304,10 @@ def test_type_comments_invalid_expression() -> None:
 def test_type_comments_invalid_function_comments() -> None:
     module = builder.parse(
         """
+    def func(
+        # type: () -> int # inside parentheses
+    ):
+        pass
     def func():
         # type: something completely invalid
         pass