Compiler segfaults when invoking a function stored in a comptime field

[tauoverpi]

Zig Version

0.10.0-dev.3952+9e070b653

Steps to Reproduce

This issue was discovered by a user on telegram (posting on their behalf as they don't have a github account).

build the following

comptime capacity: fn () u64 = capacity_,
// comptime capacity: *const fn () u64 = capacity_,
fn capacity_() u64 {
    return 64;
}

pub export fn _start() void {
    _ = (@This(){}).capacity();
}

and for the second case, the given:

const print = @import("std").debug.print;
const Auto = struct {
    auto: [max_len]u8 = undefined,
    offset: u64 = 0,

    comptime capacity: *const fn () u64 = capacity,

    const max_len: u64 = 32;

    fn length(heap: Auto) u64 {
        return heap.offset;
    }
    fn capacity() u64 {
        return max_len;
    }
};
const Heap = struct {
    start: u64,
    next: u64,
    finish: u64,

    fn length(heap: Heap) u64 {
        return heap.next - heap.start;
    }
    fn capacity(heap: Heap) u64 {
        return heap.finish - heap.start;
    }
};
fn doPrint(any: anytype) void {
    print("offset: {d}, capacity: {d}\n", .{ any.length(), any.capacity() });
}
pub fn main() void {
    const a: Auto = .{ .offset = 16, .capacity = Auto.capacity };
    const b: Heap = .{ .start = 0x4000000, .next = 0x4000010, .finish = 0x4000020 };
    doPrint(a);
    doPrint(b);
}

Expected Behavior

Compile as this works with stage1 (first example) and not generate invalid IR (second example).

Actual Behavior

Segfault

> zig build-exe c.zig
fish: Job 1, 'zig build-exe c.zig' terminated by signal SIGSEGV (Address boundary error)

For the second one, invalid IR

><> zig run c.zig
LLVM Emit Object... LLVM ERROR: Cannot select: 0x7fa0816eeaf0: ch,glue = X86ISD::CALL 0x7fa0816eeb58, 0x7fa0816d6d90, RegisterMask:Untyped, c.zig:30:72
  0x7fa0816d6d90: i8,ch = CopyFromReg 0x7fa0818ad3e8, Register:i8 %4, c.zig:30:72
    0x7fa0816ef2a8: i8 = Register %4
  0x7fa0816d6ec8: Untyped = RegisterMask
In function: c.doPrint__anon_3733