[PATCH] D146897: [clang:diagnostics] Turning off warn_self_assignment_overloaded for user-defined compound assignments

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith added inline comments.


================
Comment at: clang/lib/Sema/SemaExpr.cpp:15656
   case BO_XorAssign:
-    DiagnoseSelfAssignment(S, LHS, RHS, OpLoc, false);
     CheckIdentityFieldAssignment(LHS, RHS, OpLoc, S);
     break;
----------------
python3kgae wrote:
> rsmith wrote:
> > This is the same thing, but for `this->x += this->x`. I think we should also suppress those warnings for compound assignment, except when one of the operands is an implicit member access and one is an explicit member access (`this->x += x;` should still warn if the latter `x` is also interpreted as `this->x`).
> For case like this:
> 
> ```
> class Vector {
> public:
>     Vector& operator+=(const Vector &v) { return *this; }
>     Vector& operator-=(const Vector &v) { return *this; }
> };
> 
> class A {
> public:
>   A(){}
>   Vector x;
>   void foo() {
>      this->x -= this->x;
>      this->x -= x;
>      this->x += this->x;
>      this->x += x;
>   }
> };
> ```
> clang will report 2 warning:
> 
> ```
> <source>:14:14: warning: assigning field to itself [-Wself-assign-field]
>      this->x -= this->x;
>              ^
> <source>:15:14: warning: assigning field to itself [-Wself-assign-field]
>      this->x -= x;
> ```
> 
> Do you mean we should make it report warning on this->x -= x; and this->x += x; ?
Let's not add any new warnings. Pretend my comment was about `-=`, not `+=`.


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