Teach the explicit constructor check about constexpr.
If a constructor is marked constexpr it evades the explicit constructor
check right now, since the check only knows about the inline keyword.
Teach it that constexpr can be used also.
diff --git a/cpplint/cpplint.py b/cpplint/cpplint.py
index 3366b39..fafc243 100755
--- a/cpplint/cpplint.py
+++ b/cpplint/cpplint.py
@@ -2779,7 +2779,8 @@
# Look for single-argument constructors that aren't marked explicit.
# Technically a valid construct, but against style.
explicit_constructor_match = Match(
- r'\s+(?:inline\s+)?(explicit\s+)?(?:inline\s+)?%s\s*'
+ r'\s+(?:(?:inline|constexpr)\s+)*(explicit\s+)?'
+ r'(?:(?:inline|constexpr)\s+)*%s\s*'
r'\(((?:[^()]|\([^()]*\))*)\)'
% re.escape(base_classname),
line)