Don't flag aliases named 'is_transparent'

Author: arxanas

lint381/cpp.py

@@ -235,6 +235,10 @@ def alias_names(source, *, match):
     alias_token = match[1]
     alias = alias_token.value
 
+    # Name mandated by the C++ standard library for heterogeneous lookup.
+    if alias == "is_transparent":
+        return
+
     if not alias[0].isupper():
         yield Error(message="Alias '{}' should be capitalized".format(alias),
                     tokens=[alias_token])

test/integ/cpp/alias_names.cpp

@@ -1,3 +1,7 @@
 using Foo = int;
 
 using bar_t = int;
+
+// Should be accepted because some comparators use this alias name for
+// heterogeneous lookup.
+using is_transparent = int;