It's even more fun than I remember. This compiles without warnings with "gcc -Wall", and produces an error (declaration of x shadows a parameter) if f4 is uncom

It's even more fun than I remember. This compiles without warnings with "gcc -Wall", and produces an error (declaration of x shadows a parameter) if f4 is uncommented struct S { int x; int f1() { int x = x; return x; } int f2(int x) { return [x=x]{return x;}(); } int f3(int x) { if (int x=x) return x; return x;} // int f4(int x) { int x=x; return x; } }; int main(){} clang warns a bit with -Wall a.cpp:5:26: warning: variable 'x' is uninitialized when used within its own initialization [-Wuninitialized] 5 | int f3(int x) { if (int x=x) return x; return x;} | ~ ^