| Issue |
107653
|
| Summary |
[clang-tidy] Request for dangling reference check for (ranges) min, max, minmax
|
| Labels |
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| Assignees |
|
| Reporter |
olologin
|
Hi, is it possible to implement dangling reference clang-tidy check that identifies bad code, for example on inputs like this:
[https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(filename:'1',fontScale:14,fontUsePx:'0',j:1,lang:c%2B%2B,selection:(endColumn:38,endLineNumber:18,positionColumn:38,positionLineNumber:18,selectionStartColumn:38,selectionStartLineNumber:18,startColumn:38,startLineNumber:18),source:'template%3Cclass+T%3E%0Aconst+T%26+min(const+T%26+a,+const+T%26+b)%0A%7B%0A++++return+(b+%3C+a)+%3F+b+:+a%3B%0A%7D%0A%0Aint+normal()%0A%7B%0A++++int+a+%3D+0%3B%0A++++int+b+%3D+0%3B%0A++++const+auto+c+%3D+min(a,+b)%3B%0A%7D%0A%0Aint+dangling()%0A%7B%0A++++const+auto%26+c+%3D+min(1,+2)%3B%0A++++int+a+%3D+2%3B%0A++++const+auto%26+d+%3D+min(a,+normal())%3B%0A++++const+auto%26+e+%3D+min(1,+a*2)%3B%0A%7D'),l:'5',n:'1',o:'C%2B%2B+source+%231',t:'0')),k:35.81213307240704,l:'4',n:'0',o:'',s:0,t:'0'),(g:!((g:!((h:compiler,i:(compiler:clang_trunk,filters:(b:'0',binary:'1',binaryObject:'1',commentOnly:'0',debugCalls:'1',demangle:'0',directives:'0',execute:'1',intel:'1',libraryCode:'0',trim:'1',verboseDemangling:'0'),flagsViewOpen:'1',fontScale:14,fontUsePx:'0',j:1,lang:c%2B%2B,libs:!(),options:'-Xclang+-ast-dump+-std%3Dc%2B%2B20',overrides:!(),selection:(endColumn:1,endLineNumber:1,positionColumn:1,positionLineNumber:1,selectionStartColumn:1,selectionStartLineNumber:1,startColumn:1,startLineNumber:1),source:1),l:'5',n:'0',o:'+x86-64+clang+(trunk)+(Editor+%231)',t:'0')),k:50.82493349378958,l:'4',m:25.357710651828295,n:'0',o:'',s:0,t:'0'),(g:!((h:output,i:(compilerName:'x86-64+clang+18.1.0',editorid:1,fontScale:14,fontUsePx:'0',j:1,wrap:'0'),l:'5',n:'0',o:'Output+of+x86-64+clang+(trunk)+(Compiler+%231)',t:'0')),header:(),l:'4',m:74.6422893481717,n:'0',o:'',s:0,t:'0')),k:64.18786692759295,l:'3',n:'0',o:'',t:'0')),l:'2',n:'0',o:'',t:'0')),version:4](godbolt with ast-dump)
Code from godbolt:
```
template<class T>
const T& min(const T& a, const T& b)
{
return (b < a) ? b : a;
}
int normal()
{
int a = 0;
int b = 0;
const auto c = min(a, b);
}
int dangling()
{
const auto& c = min(1, 2);
int a = 2;
const auto& d = min(a, normal());
const auto& e = min(1, a*2);
}
```
I guess we need to match for function min, max, minmax calls that have `MaterializeTemporaryExpr` child nodes?
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