unnecessary_to_owned causes type mismatch

Summary

Clippy will suggest turning .to_vec().into_iter() into .iter().copied() even when doing so causes a type mismatch later in the function

Lint Name

unnecessary_to_owned

Reproducer

I tried this code:

full code

let mut foos_left = FOOS.to_vec().into_iter().filter(make_filter(true, 'b'));
foos_left = foos_left
    .collect::<Vec<_>>()
    .into_iter()
    .filter(make_filter(false, 'z'));

I saw this happen:

warning: unnecessary use of `to_vec`
  --> src/main.rs:17:25
   |
17 |     let mut foos_left = FOOS.to_vec().into_iter().filter(make_filter(true, 'b'));
   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `FOOS.iter().copied()`
   |
   = note: `#[warn(clippy::unnecessary_to_owned)]` on by default
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_to_owned

I expected to see this happen:
Nothing; applying the change causes a type mismatch error because the type of foos_left changes

Version

rustc 1.63.0-nightly (e09449220 2022-05-31)
binary: rustc
commit-hash: e0944922007e1bb4fe59809293acf4364410cccc
commit-date: 2022-05-31
host: x86_64-unknown-linux-gnu
release: 1.63.0-nightly
LLVM version: 14.0.4

Additional Labels

@rustbot label +l-suggestion-causes-error

Begin with the linked Rust Playground reproducer and the unnecessary_to_owned lint. Compare the suggested iter().copied() form with the original to identify why reassignment changes the type. Done means the lint no longer suggests a change that produces a type mismatch, with regression coverage for the reproducer.