From 5eaa50f1d5191ae74e0a1bbe60e8d1fcf36507e3 Mon Sep 17 00:00:00 2001
From: Simon Breidenbach <breidenbach0@users.noreply.github.com>
Date: Wed, 29 Jul 2026 14:48:00 +0200
Subject: [PATCH 1/2] fix(braces): exempt C++20 templated lambdas from
 trailing-semicolon check

A C++20 templated lambda like []<typename T>(T&& t) { ... }; was falsely
flagged with readability/braces 'You don't need a ; after a }'. The lambda
exemption relied on the text before '(' ending in ']' (the capture), but a
template parameter list sits between ']' and '(' so the prefix ends in '>'
and the exemption missed it. Also recognize the ]<...> introducer.

Fixes #385
---
 CHANGELOG.rst       |  1 +
 cpplint.py          |  1 +
 cpplint_unittest.py | 17 +++++++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 4127d4e..bfe5f32 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -6,6 +6,7 @@ TBA
 ===
 
 * Fixed a whitespace/newline false positive for control conditions containing lambdas. (#410)
+* Fixed a false positive where C++20 templated lambdas (``[]<T>(...)``) triggered the redundant trailing semicolon warning. (#385)
 
 2.0.2 (2025-04-08)
 ===========
diff --git a/cpplint.py b/cpplint.py
index 07687d2..cacf69e 100755
--- a/cpplint.py
+++ b/cpplint.py
@@ -5186,6 +5186,7 @@ def CheckTrailingSemicolon(filename, clean_lines, linenum, error):
                     )
                 )
                 or (func and not re.search(r"\boperator\s*\[\s*\]", func.group(1)))
+                or re.search(r"\]\s*<.*>\s*$", line_prefix)
                 or re.search(r"\b(?:struct|union)\s+alignas\s*$", line_prefix)
                 or re.search(r"\bdecltype$", line_prefix)
                 or re.search(r"\brequires.*$", line_prefix)
diff --git a/cpplint_unittest.py b/cpplint_unittest.py
index d568251..38cf6e7 100755
--- a/cpplint_unittest.py
+++ b/cpplint_unittest.py
@@ -3186,6 +3186,23 @@ def testLambda(self):
         # Avoid false positives with operator[]
         self.TestLint("table_to_children[&*table].push_back(dependent);", "")
 
+        # C++20 templated lambdas: []<T>(...) must not trigger the redundant
+        # trailing semicolon check. Regression test for #385.
+        self.TestLint("auto x = []<typename T>(T) {};", "")
+        self.TestLint("auto x = [&]<typename T, int N>(T (&a)[N]) {};", "")
+        self.TestMultiLineLint(
+            "auto x = []<typename T>(T t) {\n"
+            "  return t;\n"
+            "};\n",
+            "",
+        )
+        # A templated *function* (not a lambda) with a redundant trailing
+        # semicolon must still be flagged.
+        self.TestLint(
+            "template <typename T> void f() {};",
+            "You don't need a ; after a }  [readability/braces] [4]",
+        )
+
     def testBraceInitializerList(self):
         self.TestLint("MyStruct p = {1, 2};", "")
         self.TestLint("MyStruct p{1, 2};", "")

From c6a64d4409fe1f1707b3fbc5b46606cee5628069 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Fri, 31 Jul 2026 18:57:06 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 cpplint_unittest.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/cpplint_unittest.py b/cpplint_unittest.py
index 38cf6e7..876c51b 100755
--- a/cpplint_unittest.py
+++ b/cpplint_unittest.py
@@ -3191,9 +3191,7 @@ def testLambda(self):
         self.TestLint("auto x = []<typename T>(T) {};", "")
         self.TestLint("auto x = [&]<typename T, int N>(T (&a)[N]) {};", "")
         self.TestMultiLineLint(
-            "auto x = []<typename T>(T t) {\n"
-            "  return t;\n"
-            "};\n",
+            "auto x = []<typename T>(T t) {\n  return t;\n};\n",
             "",
         )
         # A templated *function* (not a lambda) with a redundant trailing