Proposal: make errdefer in function not returning an error union a compile error

[ifreund]

The following compiles despite the errdefer being dead code:

const std = @import("std");

pub fn main() void {
    errdefer std.debug.warn("I'm alive!\n", .{});
    std.debug.warn("hello world!\n", .{});
}

Making this a compile error would avoid dead code hanging around after refactoring.

[Vexu]

Duplicate of #2654.

[ifreund]

whoops, should've searched first :D