Cannot add an exception to #[deny(lint group)] with #[warn(specific lint)] #41941

#![deny(warnings)]
#![warn(illegal_floating_point_literal_pattern)]

fn main() {
    if let 0.0 = 1.0 {}
}

error: floating-point literals cannot be used in patterns
 --> a.rs:5:12
  |
5 |     if let 0.0 = 1.0 {}
  |            ^^^
  |
  = note: #[deny(illegal_floating_point_literal_pattern)] implied by #[deny(warnings)]
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
note: lint level defined here
 --> a.rs:1:9
  |
1 | #![deny(warnings)]
  |         ^^^^^^^^

ERROR:rustc_lint::builtin: span mc spanspam
error: aborting due to previous error

#![deny(warnings)]
#![allow(illegal_floating_point_literal_pattern)]

fn main() {
    if let 0.0 = 1.0 {}
}