[clang-tidy] modernize-use-trailing-return-type fix #44206

[bernhardmgruber]

Summary

prevent rewrite when an unqualified id in a typedef type collides with a function argument name

Fixes #44206.

[bernhardmgruber]

Fixed whitespace in test code.

[aaron.ballman]

LGTM!

[bernhardmgruber]

Thank you for the quick review! Can you please commit it for me as well? Thank you!

[aaron.ballman]

In D88700#2309431, @bernhardmgruber wrote:

Thank you for the quick review! Can you please commit it for me as well? Thank you!

Happy to! I've commit on your behalf in 07028cd5dbb8417fb41121a7e75290fab00f65fc. Thank you for the fix!

[bernhardmgruber]

clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

72

There is a break; missing after this line. The build bot just told me. It should not change the meaning of the program though.

Can someone add that for me or do I need to upload another diff? Thank you!

[aaron.ballman]

clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

72

I'll take care of it, thanks for letting me know!

[bernhardmgruber]

clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

72

Great! Thank you for the help!

[aaron.ballman]

clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

72

Any time! The fix is in 089e628b61f929ccd26565cd4118395f0a0273c3

clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp

if (!Elaborated) {
       case TypeLoc::TemplateSpecialization:
         if (VisitUnqualName(TL.getAs<TemplateSpecializationTypeLoc>()
                                 .getTypePtr()
                                 ->getTemplateName()
                                 .getAsTemplateDecl()
                                 ->getName()))
           return false;
         break;
+      case TypeLoc::Typedef:
+        if (VisitUnqualName(
+                TL.getAs<TypedefTypeLoc>().getTypePtr()->getDecl()->getName()))
+          return false;
       default:
         break;
       }
     }
 
     return RecursiveASTVisitor<UnqualNameVisitor>::TraverseTypeLoc(TL);
   }
 

clang-tools-extra/test/clang-tidy/checkers/modernize-use-trailing-return-type.cpp

 // RUN: %check_clang_tidy -std=c++14-or-later %s modernize-use-trailing-return-type %t -- -- -fdeclspec -fexceptions -DCOMMAND_LINE_INT=int
 
 namespace std {
     template <typename T>
     class vector;
 
     template <typename T, int N>
     class array;
 
     class string;
 
-    class ostream;
+    template <typename T>
+    class basic_ostream;
+
+    using ostream = basic_ostream<char>;
 
     template <typename T>
     auto declval() -> T;
+
+    template <typename... Ts>
+    class tuple;
 }
 
 //
 // Functions
 //
 
 int f();
 // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return-type]

 // CHECK-FIXES: {{^}}vector<Object> j5(unsigned vector);{{$}}
 constexpr auto Size = 5;
 std::array<int, Size> j6(unsigned Size);
 // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: use a trailing return type for this function [modernize-use-trailing-return-type]
 // CHECK-FIXES: {{^}}std::array<int, Size> j6(unsigned Size);{{$}}
 std::array<decltype(Size), (Size * 2) + 1> j8(unsigned Size);
 // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: use a trailing return type for this function [modernize-use-trailing-return-type]
 // CHECK-FIXES: {{^}}std::array<decltype(Size), (Size * 2) + 1> j8(unsigned Size);{{$}}
+using std::ostream;
+std::tuple<int, std::string, ostream>& operator<<(ostream& ostream, float i);
+// CHECK-MESSAGES: :[[@LINE-1]]:40: warning: use a trailing return type for this function [modernize-use-trailing-return-type]
+// CHECK-FIXES: {{^}}std::tuple<int, std::string, ostream>& operator<<(ostream& ostream, float i);{{$}}
 
 class CC {
     int Object;
     struct Object m();
 // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: use a trailing return type for this function [modernize-use-trailing-return-type]
 // CHECK-FIXES: {{^}}    auto m() -> struct Object;{{$}}
 };
 Object CC::m() { return {0}; }

 // CHECK-FIXES: {{^}}auto DD::g() -> Object {{{$}}
     return {0};
 }
 
 //
 // bug 44206, no rewrite should happen due to collision with parameter name
 //
 
-using std::ostream;
 ostream& operator<<(ostream& ostream, int i);
 // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use a trailing return type for this function [modernize-use-trailing-return-type]
 // CHECK-FIXES: {{^}}ostream& operator<<(ostream& ostream, int i);{{$}}
 
 //
 // Samples which do not trigger the check
 //