// MIR for `mem_replace` after PreCodegen fn mem_replace(_1: &mut u32, _2: u32) -> u32 { debug r => _1; debug v => _2; let mut _0: u32; scope 1 (inlined std::mem::replace::) { scope 2 { scope 4 (inlined std::ptr::write::) { } } scope 3 (inlined std::ptr::read::) { } } bb0: { _0 = (*_1); (*_1) = _2; return; } }