In C++, if you leave the capture specifier at the beginning of a lambda expression empty (e.g. [](int x) { return x + 1; }), you can't capture variables from outer scopes, so you effectively have an anonymous function without inheritance. Non-capturing lambdas can be coerced to regular function pointers, so they behave almost identically to true functions, though they technically have different types (before being coerced).

Rust also allows the "non-capturing lambda to function pointer" conversion but (for better or worse) doesn't have explicit syntax for non-capturing lambdas; a lambda automatically qualifies if it doesn't mention any outer variable names.