Wrong `try_into` for enum variant if `Result` is shadowed

If std::result::Result is shadowed, the "Generate a try_into_ method for this enum variant" code action produces a wrong return type.

Setup

There is a Result type which shadows the std::result::Result from the prelude.

The "Generate a try_into_ method for this enum variant" code action produces wrong code, because it uses the Result type instead of StdResult.

The "Implement missing members" code action for the FromStr trait does correctly use StdResult.

use std::{result::Result as StdResult, str::FromStr};

pub type Result<T> = StdResult<T, ()>;

enum A {
    B(String),
}

// --- code below is generated ---

impl A {
    fn try_into_b(self) -> Result<String, Self> {
        if let Self::B(v) = self {
            Ok(v)
        } else {
            Err(self)
        }
    }
}

impl FromStr for A {
    type Err;

    fn from_str(s: &str) -> StdResult<Self, Self::Err> {
        todo!()
    }
}

Versions

rust-analyzer version: 0.3.1831-standalone

rustc version: rustc 1.75.0 (82e1608df 2023-12-21)

relevant settings: none

Thanks to @japaric for finding.

Start by locating the implementation of the “Generate a try_into_ method for this enum variant” code action and compare it with the FromStr “Implement missing members” action described in the issue. Reproduce the shadowed-Result example, then verify that the generated return type remains the standard Result and add regression coverage for the case.