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-rw-r--r--src/test/ui/mir-dataflow/def-inits-1.rs51
1 files changed, 51 insertions, 0 deletions
diff --git a/src/test/ui/mir-dataflow/def-inits-1.rs b/src/test/ui/mir-dataflow/def-inits-1.rs
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+++ b/src/test/ui/mir-dataflow/def-inits-1.rs
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+// 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_definite_init,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); //~ ERROR rustc_peek: bit not set
+
+ // All function formal parameters start off initialized.
+
+ rustc_peek(&x);
+ rustc_peek(&y);
+ rustc_peek(&z);
+
+ ret = if test {
+ ::std::mem::replace(x, y)
+ } else {
+ z = y;
+ z
+ };
+
+ // `z` may be uninitialized here.
+ rustc_peek(&z); //~ ERROR rustc_peek: bit not set
+
+ // `y` is definitely uninitialized here.
+ rustc_peek(&y); //~ ERROR rustc_peek: bit not set
+
+ // `x` is still (definitely) initialized (replace above is a reborrow).
+ rustc_peek(&x);
+
+ ::std::mem::drop(x);
+
+ // `x` is *definitely* uninitialized here
+ rustc_peek(&x); //~ ERROR rustc_peek: bit not set
+
+ // `ret` is now definitely initialized (via `if` above).
+ rustc_peek(&ret);
+
+ ret
+}
+fn main() {
+ foo(true, &mut S(13), S(14), S(15));
+ foo(false, &mut S(13), S(14), S(15));
+}