if_same_then_else does not detect same `if let` expression

Lint name: if_same_then_else

I tried this code: https://github.com/deltachat/deltachat-core-rust/blob/master/src/message.rs#L1081-L1091

                        if chat.id.is_deaddrop() {
                            if let Some(contact) = contact {
                                self.text1 = Some(msg.get_sender_name(contact));
                            } else {
                                self.text1 = None;
                            }
                        } else if let Some(contact) = contact {
                            self.text1 = Some(msg.get_sender_name(contact));
                        } else {
                            self.text1 = None;
                        }

I expected to see this happen: detect that chat.id.is_deaddrop() condition could be removed.

Instead, this happened: clippy did not detect anything.

Meta

• cargo clippy -V: clippy 0.0.212 (e1884a8 2020-12-29)
• rustc -Vv:

  rustc 1.49.0 (e1884a8e3 2020-12-29)
  binary: rustc
  commit-hash: e1884a8e3c3e813aada8254edfa120e85bf5ffca
  commit-date: 2020-12-29
  host: x86_64-unknown-linux-gnu
  release: 1.49.0
  

Start with the linked src/message.rs example around lines 1081-1091 and reproduce the behavior using cargo clippy. Trace the if_same_then_else lint entry point and its existing coverage, then add detection for this repeated if let expression and verify that Clippy reports the removable condition.