[Issue 15544] New: Escaping fields to a heap delegate must be disallowed in @safe code

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15544

          Issue ID: 15544
           Summary: Escaping fields to a heap delegate must be disallowed
                    in @safe code
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: sludwig at outerproduct.org

>From https://github.com/rejectedsoftware/vibe.d/issues/570

The following code currently compiles fine, but results in a dangling reference
to "this.x" when the delegate gets called after the life time of the
originating "Test" instance. At least in @safe code, taking the address of a
struct field of "this" within a non-scoped delegate must instead result in a
compile-time error.

---
void delegate() @safe _del;

struct Test {
  int x = 42;
  @safe void test() {
    _del = { assert(x == 42); };
 }
}
---

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