Invalid clippy suggestion for !(a as type >= b)

[folkertdev]

Summary

it would be really surprising to me if this is not a duplicate, but I can't find a similar issue yet.

The problem is that in the right-hand side of an as ... expression, a < is interpreted as starting a generic instantiation (as in as Foo<Bar>. Hence, the suggestion needs to include extra parentheses so that the < in interpreted as a comparison operator as intended.

Reproducer

I tried this code:

fn main() {
    let b = 0;
    let a = 0;

    if !(a as std::ffi::c_uint >= b) {
        // ...
    }
}

I expected to see this happen:

warning: this boolean expression can be simplified
 --> src/main.rs:5:8
  |
5 |     if !(a as std::ffi::c_uint >= b) {
  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(a as std::ffi::c_uint) < b`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
  = note: `#[warn(clippy::nonminimal_bool)]` on by default

Instead, this happened:

warning: this boolean expression can be simplified
 --> src/main.rs:5:8
  |
5 |     if !(a as std::ffi::c_uint >= b) {
  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `a as std::ffi::c_uint < b`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool
  = note: `#[warn(clippy::nonminimal_bool)]` on by default

This blows up with cargo clippy --fix also:

> 
cargo clippy --fix --allow-dirty --allow-staged --broken-code
    Checking playground v0.1.0 (/home/folkertdev/rust/playground)
warning: failed to automatically apply fixes suggested by rustc to crate `playground`

after fixes were automatically applied the compiler reported errors within these files:

  * src/main.rs

This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust-clippy/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag

The following errors were reported:
error: `<` is interpreted as a start of generic arguments for `std::ffi::c_uint`, not a comparison
 --> src/main.rs:5:30
  |
5 |     if a as std::ffi::c_uint < b {
  |                              ^ --- interpreted as generic arguments
  |                              |
  |                              not interpreted as comparison
  |
help: try comparing the cast value
  |
5 |     if (a as std::ffi::c_uint) < b {
  |        +                     +

error: aborting due to 1 previous error

Version

$ rustc --version --verbose
rustc 1.77.0 (aedd173a2 2024-03-17)
binary: rustc
commit-hash: aedd173a2c086e558c2b66d3743b344f977621a7
commit-date: 2024-03-17
host: x86_64-unknown-linux-gnu
release: 1.77.0
LLVM version: 17.0.6

Additional Labels

No response