readability-redundant-string-cstr doesn't catch c_str() calls in make_pair

[Quuxplusone]

Bugzilla Link	PR24824
Status	NEW
Importance	P normal
Reported by	Eugene Zelenko (eugene.zelenko@gmail.com)
Reported on	2015-09-15 13:11:24 -0700
Last modified on	2016-01-18 23:14:17 -0800
Version	unspecified
Hardware	PC Linux
CC	adrian@adek.io, alexfh@google.com, djasper@google.com, klimek@google.com
Fixed by commit(s)
Attachments	AST (7126 bytes, application/octet-stream)
Blocks
Blocked by
See also

Created attachment 14882
AST generated from my code

readability-redundant-string-cstr doesn't catch c_str() calls in make_pair.

Sample situation:

std::map<std::string, int> Map;
std::string Key( "Key" );

Map.insert( std::make_pair( Key.c_str(), 1 ) );

I use GCC 4.8.3 STL. I tried both 3.7 and trunk clang-tidy.

[Quuxplusone]

Attached AST (7126 bytes, application/octet-stream): AST generated from my code

[Quuxplusone]

From what I can tell after reading the code of this check, the way matchers are
registered implies that this is catching only "direct" mismatch between
arguments. Here, when I look at the AST, there is an implicit conversion
happening from std::pair<const char*, int> to std::pair<std::string, int> which
by no means is detected by this check.

I don't have much experience in writing this kind of semantic checks, but it
seems that it would need to match any function which expects std::string. Then,
the parameter which is of the std::string would have to be tracked down the AST
to get the origin (more than one layer, e.g. implicit conversions, temporaries,
...) of the value. This value, should be checked for a presence of .c_str()
call.

Can someone point to an existing solution which does a similar thing? I am sure
there are some more complex analysis already implemented, which might help in
shaping the solution.