53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
// issue-0008: protocol value created in a function and appended to a list
|
|
// still stores a dangling stack pointer (issue-0007 fix incomplete)
|
|
//
|
|
// When a concrete value is converted to a protocol value inside a function
|
|
// (either implicitly via append or explicitly) and stored in a List, the
|
|
// protocol data pointer targets the function's stack frame instead of a
|
|
// heap-allocated copy.
|
|
//
|
|
// After the function returns, the first dispatch may succeed (stack not yet
|
|
// overwritten), but subsequent dispatches crash because the stack memory has
|
|
// been reused by other calls.
|
|
//
|
|
// STATUS: open — issue-0007 fix only covers some cases
|
|
|
|
#import "modules/std.sx";
|
|
|
|
Sizable :: protocol {
|
|
size :: () -> s64;
|
|
}
|
|
|
|
Leaf :: struct { value: s64; }
|
|
impl Sizable for Leaf {
|
|
size :: (self: *Leaf) -> s64 { self.value; }
|
|
}
|
|
|
|
add :: (items: *List(Sizable), w: Leaf) {
|
|
p := w;
|
|
items.append(p); // protocol value created from stack local `p`
|
|
}
|
|
|
|
main :: () -> void {
|
|
// Works: protocol value created in main, appended to list
|
|
out("=== Created in main ===\n");
|
|
list_a : List(Sizable) = .{};
|
|
s : Sizable = Leaf.{ value = 42 };
|
|
list_a.append(s);
|
|
r1 := list_a.items[0].size();
|
|
print("first: {} (expected 42)\n", r1);
|
|
r2 := list_a.items[0].size();
|
|
print("second: {} (expected 42)\n", r2);
|
|
|
|
// BUG: protocol value created in add(), first dispatch works, second crashes
|
|
out("=== Created in add() ===\n");
|
|
list_b : List(Sizable) = .{};
|
|
add(@list_b, Leaf.{ value = 99 });
|
|
r3 := list_b.items[0].size();
|
|
print("first: {} (expected 99)\n", r3); // works (stack not yet clobbered)
|
|
r4 := list_b.items[0].size();
|
|
print("second: {} (expected 99)\n", r4); // CRASH: stack memory reused
|
|
|
|
out("=== OK ===\n");
|
|
}
|