Rollup merge of #115936 - oli-obk:inline_const_promotion, r=RalfJung

Prevent promotion of const fn calls in inline consts

We don't wanna make that mistake we did for statics and consts worse by letting more code use it.

r? ``@RalfJung``

cc https://github.com/rust-lang/rust/issues/76001

2 files changed, 36 insertions, 0 deletions

diff --git a/tests/ui/inline-const/promotion.rs b/tests/ui/inline-const/promotion.rs
new file mode 100644
index 00000000000..242959c6b51
--- /dev/null
+++ b/tests/ui/inline-const/promotion.rs
@@ -0,0 +1,22 @@
+#![feature(inline_const)]
+#![allow(arithmetic_overflow, unconditional_panic)]
+
+// The only way to have promoteds that fail is in `const fn` called from `const`/`static`.
+// Make sure that in a `const` block, we do not promote such calls.
+const fn div_by_zero() -> i32 {
+    1 / 0
+}
+
+const fn mk_false() -> bool {
+    false
+}
+
+fn main() {
+    let v = const {
+        if mk_false() {
+            let _x: &'static i32 = &div_by_zero();
+            //~^ ERROR: temporary value dropped while borrowed
+        }
+        42
+    };
+}
diff --git a/tests/ui/inline-const/promotion.stderr b/tests/ui/inline-const/promotion.stderr
new file mode 100644
index 00000000000..795fc8f5921
--- /dev/null
+++ b/tests/ui/inline-const/promotion.stderr
@@ -0,0 +1,14 @@
+error[E0716]: temporary value dropped while borrowed
+  --> $DIR/promotion.rs:17:37
+   |
+LL |             let _x: &'static i32 = &div_by_zero();
+   |                     ------------    ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
+   |                     |
+   |                     type annotation requires that borrow lasts for `'static`
+LL |
+LL |         }
+   |         - temporary value is freed at the end of this statement
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0716`.