"Inline variable" code action is buggy when variable is shadowed

I have a chunk of code that looks like this

fn foo(a: usize) -> usize {
  let b = a;
  let a = a + 1;
  b * 2;
}

If I place the cursor on b in let b = a;, and ask rust-analyzer to inline it, it happily produces

fn foo(a: usize) -> usize {
  let a = a + 1;
  a * 2;
}

which is not the same thing semantically.

rust-analyzer version: (eg. output of "rust-analyzer: Show RA Version" command, accessible in VSCode via Ctrl/⌘+Shift+P)

2023-03-06

rustc version: (eg. output of rustc -V)

rustc 1.70.0-nightly (28a29282f 2023-04-06)

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)

accessed via rustic-mode in doom emacs

Start by reproducing the inline-variable action with the shadowed a example in the issue. Trace the inline-variable code action and its handling of bindings, then verify that applying it preserves the original value and add coverage for this shadowing case if the relevant test location is identified.