let ty = fcx.tcx.erase_regions(ty);
let expr_ty = fcx.resolve_vars_if_possible(self.expr_ty);
let expr_ty = fcx.tcx.erase_regions(expr_ty);
let ty = fcx.tcx.erase_regions(ty);
let expr_ty = fcx.resolve_vars_if_possible(self.expr_ty);
let expr_ty = fcx.tcx.erase_regions(expr_ty);