Bug 15195 – DIP25: Member functions can leak local variables

The following code leaks a reference to a local variable: ref int foo()@safe{ int x; struct S{ ref int bar(){ return x; } } S s; return s.bar(); } It is not enough to require 'return' on member functions if the returned reference is not guaranteed to outlive the 'this' pointer. (This is closely related to issue 15192.)

The compiler actually allocates a closure (so unlike the other DIP25 bug reports, there is no memory corruption here.) I'm not sure what the intended behaviour is. The closure is allocated even in the following case: void foo()@nogc{ int x; struct S{ int bar()@nogc{ return x; } } S s; } Error: function foo @nogc function allocates a closure with the GC

Passing the address of a local variable to a nested function causes a closure to be allocated. It's working as designed, though the analysis is unsophisticated and could potentially be improved, so marked as an enhancement request.

(In reply to Walter Bright from comment #2) > Passing the address of a local variable to a nested function causes a > closure to be allocated. It's working as designed, though the analysis is > unsophisticated and could potentially be improved, so marked as an > enhancement request. I have opened https://issues.dlang.org/show_bug.cgi?id=15232. I'm closing this issue.