findTrackableFields

pub fn findTrackableFields(
    zir: *const Zir,
    gpa: Allocator,
    contents: *DeclContents,
    type_decl_inst: Zir.Inst.Index,
) Allocator.Error!void {
    contents.clear();

    var found_defers: std.AutoHashMapUnmanaged(u32, void) = .empty;
    defer found_defers.deinit(gpa);

    assert(zir.instructions.items(.tag)[@backingInt(type_decl_inst)] == .extended);
    switch (zir.instructions.items(.data)[@backingInt(type_decl_inst)].extended.opcode) {
        .struct_decl => {
            const struct_decl = zir.getStructDecl(type_decl_inst);
            var it = struct_decl.iterateFields();
            while (it.next()) |field| {
                try zir.findTrackableBody(gpa, contents, &found_defers, field.type_body);
                if (field.align_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
                if (field.default_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
            }
        },
        .union_decl => {
            const union_decl = zir.getUnionDecl(type_decl_inst);
            var it = union_decl.iterateFields();
            while (it.next()) |field| {
                if (field.type_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
                if (field.align_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
                if (field.value_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
            }
        },
        .enum_decl => {
            const enum_decl = zir.getEnumDecl(type_decl_inst);
            var it = enum_decl.iterateFields();
            while (it.next()) |field| {
                if (field.value_body) |b| try zir.findTrackableBody(gpa, contents, &found_defers, b);
            }
        },
        .opaque_decl => {},
        else => unreachable,
    }
}