Compiler allows for wrong struct initialization

[ldanko]

By mistake I used recursively Default::default() inside Default::default() implementation.
Compilation suceeded, but program crashed on illegal instruction.

I tried this code:

struct A {
    x: i32,
}

impl Default for A {
    fn default() -> A {
        A {
            x: 1
        }
    }
}

struct B {
    x: i32,
    a: A
}

impl Default for B {
    fn default() -> B {
        B {
            x: 5,
            ..Default::default()
        }
    }
}

fn main() {
    let _b = B {..Default::default()};

}

I expected to see this happen: compiler error

Instead, this happened: compilation succeeded, program crashes (illegal instruction)

Meta

rustc --version --verbose:

rustc 1.1.0 (35ceea399 2015-06-19)
binary: rustc
commit-hash: 35ceea3997c79a3b7562e89b462ab76af5b86b22
commit-date: 2015-06-19
host: x86_64-unknown-linux-gnu
release: 1.1.0

Backtrace:

thread '<main>' has overflowed its stack

Program received signal SIGILL, Illegal instruction.
0x000055555555b97e in rust_stack_exhausted ()
(gdb) bt
#0  0x000055555555b97e in rust_stack_exhausted ()
#1  0x00005555555590c1 in __morestack ()
#2  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
#3  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
#4  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
#5  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
#6  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
#7  0x000055555555900b in B.Default::default::h3de843a3f3bb0910zaa ()
(...)

[ldanko]

This may be related to #24732

[eefriedman]

See also #26783.

[eddyb]

The SIGILL is an intentional abort triggered by the stack overflow handling code.
The important part is thread '<main>' has overflowed its stack.
Even with #26783, this would only be a warning, Rust does not statically prevent infinite recursion.

[huonw]

Dupe of #18785.

Thanks for filing!