no optimization of Some(v).unwrap() to v for certain types of v

[antonilol]

I tried this code:

pub fn example(vec: Vec<u32>) -> Vec<u32> {
    Some(vec).unwrap() 
}

I expected to see this happen: a simple move

Instead, this happened: extra logic was added to check for None

see https://godbolt.org/z/sozWosj88

this does not happen with u32 and &Vec<u32>: https://godbolt.org/z/crhePq97z

Meta

godbolt's rustc version:

rustc 1.71.0-nightly (dbba59457 2023-05-01)

[Jules-Bertholet]

@rustbot label A-codegen I-heavy I-slow

[saethlin]

FWIW I previously reported this: #93011

[workingjubilee]

Thank you for reporting! Closing as duplicate.