gh-151128: Improve SyntaxError message for cross language keywords (GH-151129)

Author: zang-langyan

Lib/test/test_traceback.py

@@ -1815,6 +1815,18 @@ class TestKeywordTypoSuggestions(unittest.TestCase):
         ("[x for x\nin range(3)\nof x]", "if"),
         ("[123 fur x\nin range(3)\nif x]", "for"),
         ("for x im n:\n  pass", "in"),
+        ("mach x:", "match"),
+        ("math x:", "match"),
+        ("match 1:\n  cse 1:", "case"),
+        ("typ x = int", "type"),
+        ("typed x = int", "type"),
+        ("lazi import x", "lazy"),
+        ("lezi import x", "lazy"),
+        ("switch x:\n case:", "match"),
+        ("delete x", "del"),
+        ("function f():", "def"),
+        ("func f():", "def"),
+        ("void f():", "def"),
     ]
 
     def test_keyword_suggestions_from_file(self):

Lib/traceback.py

@@ -1485,11 +1485,22 @@ def _find_keyword_typos(self):
             # Limit the number of possible matches to try
             max_matches = 3
             matches = []
+
+            hint = _get_cross_language_keyword_hint(wrong_name)
+            if hint:
+                matches.append(hint)
             if _suggestions is not None:
-                suggestion = _suggestions._generate_suggestions(keyword.kwlist, wrong_name)
+                suggestion = _suggestions._generate_suggestions(keyword.kwlist + keyword.softkwlist, wrong_name)
                 if suggestion:
                     matches.append(suggestion)
-            matches.extend(difflib.get_close_matches(wrong_name, keyword.kwlist, n=max_matches, cutoff=0.5))
+            matches.extend(
+                difflib.get_close_matches(
+                    wrong_name,
+                    keyword.kwlist + keyword.softkwlist,
+                    n=max_matches,
+                    cutoff=0.5
+                )
+            )
             matches = matches[:max_matches]
             for suggestion in matches:
                 if not suggestion or suggestion == wrong_name:
@@ -1787,6 +1798,17 @@ def print(self, *, file=None, chain=True, **kwargs):
 })
 
 
+# Cross-language keyword suggestions.
+_CROSS_LANGUAGE_KEYWORD_HINTS = frozendict({
+    # C/C++ equivalents
+    'switch': 'match',
+    'delete': 'del',
+    # function define equivalents
+    'function': 'def',
+    'func': 'def',
+    'void': 'def',
+})
+
 def _substitution_cost(ch_a, ch_b):
     if ch_a == ch_b:
         return 0
@@ -1866,6 +1888,12 @@ def _get_cross_language_hint(obj, wrong_name):
     return None
 
 
+def _get_cross_language_keyword_hint(wrong_name):
+    """Check if wrong_name is a common keyword from another language
+    """
+    return _CROSS_LANGUAGE_KEYWORD_HINTS.get(wrong_name)
+
+
 def _get_safe___dir__(obj):
     # Use obj.__dir__() to avoid a TypeError when calling dir(obj).
     # See gh-131001 and gh-139933.

Misc/NEWS.d/next/Library/2026-06-12-00-17-29.gh-issue-151128.-LYO3a.rst

@@ -0,0 +1,3 @@
+Cross-language keyword suggestions are now shown for :exc:`SyntaxError` messages.
+For example, ``switch x:`` suggests ``match``, ``delete x`` suggests ``del``,
+``function f():`` suggests ``def``. Contributed by Zang Langyan.