segmentation fault when initializing dereferenced struct defined directly in function call with var

[viviicat]

Zig Version

0.9.0, 0.10.0-dev.2977+7d2e14267

Steps to Reproduce

The following minimal reproduction produces a segfault when assigning baz to the struct. If baz is made const the segfault goes away.

const Foo = struct {
    a: Bar,
};

const Bar = struct {
    b: u32,
};

pub fn doCrash(foo: *const Foo) void {
    _ = foo;
}

test "segfault" {
    var baz: u32 = 24;

    doCrash(&.{
        .a = .{
            .b = baz,
        },
    });
}

Expected Behavior

I would expect this to either fail compilation, or properly assign 24 to Foo.Bar.b.

Actual Behavior

Test [1/1] test "segfault"... Segmentation fault at address 0x20551c
/home/vv/Projects/zig-bugs/zig-minimal-array-pointer-struct.zig:18:18: 0x208292 in test "segfault" (test)
            .b = baz,
                 ^

It's not immediately obvious to me why the segfault occurs. Perhaps it is because the struct memory is actually initialized inside the doCrash stack, so it does not have access to baz at that scope?

More alarmingly, in an expanded example, this pattern actually caused a segfault in the compiler. I have yet to figure out how to create a minimal repro of the compiler crash, but perhaps the runtime crash will assist in resolving that, since they both segfault.

I have reproduced this on master, as well as 0.9.0 on Godbolt