https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85523
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2018-04-25 Ever confirmed|0 |1 --- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- With that patch -fdiagnostics-generate-patch produces: ret.cc: In member function 'X& X::operator=(const X&)': ret.cc:2:28: warning: no return statement in function returning non-void [-Wreturn-type] X& operator=(const X&) { } // show fix-it ^ ret.cc:2:28: note: assignment operators usually return *this X& operator=(const X&) { } // show fix-it ^ return *this; ret.cc: In member function 'int Y::operator=(int)': ret.cc:7:24: warning: no return statement in function returning non-void [-Wreturn-type] int operator=(int) { } // no fix-it here, just a -Wreturn-type warning ^ ret.cc: In member function 'Z& Z::operator=(const Z&)': ret.cc:13:3: warning: no return statement in function returning non-void [-Wreturn-type] } // show fix-it ^ ret.cc:13:3: note: assignment operators usually return *this } // show fix-it ^ return *this; --- ret.cc +++ ret.cc @@ -1,5 +1,5 @@ struct X { - X& operator=(const X&) { } // show fix-it + X& operator=(const X&) { return *this;} // show fix-it }; struct Y { @@ -10,7 +10,7 @@ struct Z { Z& operator=(const Z& z) { i = z.i; - } // show fix-it + return *this;} // show fix-it int i; }; On IRC Dave said: to do it right, should handle both single-line and multiline methods and indent to match that of nearby code; see that add_newline_fixit_with_indentation from https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00334.html probably a trailing space for the single-line case