From 218caa410aa38c29984be31a5229b9fa717560ee Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:19:13 +0200 Subject: Merging upstream version 1.68.2+dfsg1. Signed-off-by: Daniel Baumann --- tests/ui/mir-dataflow/uninits-1.rs | 51 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 tests/ui/mir-dataflow/uninits-1.rs (limited to 'tests/ui/mir-dataflow/uninits-1.rs') diff --git a/tests/ui/mir-dataflow/uninits-1.rs b/tests/ui/mir-dataflow/uninits-1.rs new file mode 100644 index 000000000..c2b4284a7 --- /dev/null +++ b/tests/ui/mir-dataflow/uninits-1.rs @@ -0,0 +1,51 @@ +// General test of maybe_uninits state computed by MIR dataflow. + +#![feature(core_intrinsics, rustc_attrs)] + +use std::intrinsics::rustc_peek; +use std::mem::{drop, replace}; + +struct S(i32); + +#[rustc_mir(rustc_peek_maybe_uninit,stop_after_dataflow)] +fn foo(test: bool, x: &mut S, y: S, mut z: S) -> S { + let ret; + // `ret` starts off uninitialized + rustc_peek(&ret); + + // All function formal parameters start off initialized. + + rustc_peek(&x); //~ ERROR rustc_peek: bit not set + rustc_peek(&y); //~ ERROR rustc_peek: bit not set + rustc_peek(&z); //~ ERROR rustc_peek: bit not set + + ret = if test { + ::std::mem::replace(x, y) + } else { + z = y; + z + }; + + // `z` may be uninitialized here. + rustc_peek(&z); + + // `y` is definitely uninitialized here. + rustc_peek(&y); + + // `x` is still (definitely) initialized (replace above is a reborrow). + rustc_peek(&x); //~ ERROR rustc_peek: bit not set + + ::std::mem::drop(x); + + // `x` is *definitely* uninitialized here + rustc_peek(&x); + + // `ret` is now definitely initialized (via `if` above). + rustc_peek(&ret); //~ ERROR rustc_peek: bit not set + + ret +} +fn main() { + foo(true, &mut S(13), S(14), S(15)); + foo(false, &mut S(13), S(14), S(15)); +} -- cgit v1.2.3