Rollup merge of #104741 - bryangarza:bug-104588-async-track-caller, r=compiler-errors

Switch `#[track_caller]` back to a no-op unless feature gate is enabled

This patch fixes a regression, in which `#[track_caller]`, which was previously a no-op, was changed to actually turn on the behavior. This should instead only happen behind the `closure_track_caller` feature gate.

Also, add a warning for the user to understand how their code will compile depending on the feature gate being turned on or not.

Fixes #104588

4 files changed, 52 insertions, 22 deletions

diff --git a/src/test/ui/async-await/track-caller/async-closure-gate.rs b/src/test/ui/async-await/track-caller/async-closure-gate.rs
index 9593fdb1908..d9d55685599 100644
--- a/src/test/ui/async-await/track-caller/async-closure-gate.rs
+++ b/src/test/ui/async-await/track-caller/async-closure-gate.rs
@@ -5,6 +5,5 @@
 fn main() {
     let _ = #[track_caller] async || {
         //~^ ERROR `#[track_caller]` on closures is currently unstable [E0658]
-        //~| ERROR `#[track_caller]` on closures is currently unstable [E0658]
     };
 }
diff --git a/src/test/ui/async-await/track-caller/async-closure-gate.stderr b/src/test/ui/async-await/track-caller/async-closure-gate.stderr
index be3d110eccd..498f1b43b9b 100644
--- a/src/test/ui/async-await/track-caller/async-closure-gate.stderr
+++ b/src/test/ui/async-await/track-caller/async-closure-gate.stderr
@@ -7,19 +7,6 @@ LL |     let _ = #[track_caller] async || {
    = note: see issue #87417 <https://github.com/rust-lang/rust/issues/87417> for more information
    = help: add `#![feature(closure_track_caller)]` to the crate attributes to enable
 
-error[E0658]: `#[track_caller]` on closures is currently unstable
-  --> $DIR/async-closure-gate.rs:6:38
-   |
-LL |       let _ = #[track_caller] async || {
-   |  ______________________________________^
-LL | |
-LL | |
-LL | |     };
-   | |_____^
-   |
-   = note: see issue #87417 <https://github.com/rust-lang/rust/issues/87417> for more information
-   = help: add `#![feature(closure_track_caller)]` to the crate attributes to enable
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/async-await/track-caller/panic-track-caller.nofeat.stderr b/src/test/ui/async-await/track-caller/panic-track-caller.nofeat.stderr
new file mode 100644
index 00000000000..51ea225f4cb
--- /dev/null
+++ b/src/test/ui/async-await/track-caller/panic-track-caller.nofeat.stderr
@@ -0,0 +1,29 @@
+warning: `#[track_caller]` on async functions is a no-op
+  --> $DIR/panic-track-caller.rs:50:1
+   |
+LL |   #[track_caller]
+   |   ^^^^^^^^^^^^^^^
+LL | / async fn bar_track_caller() {
+LL | |     panic!()
+LL | | }
+   | |_- this function will not propagate the caller location
+   |
+   = note: see issue #87417 <https://github.com/rust-lang/rust/issues/87417> for more information
+   = help: add `#![feature(closure_track_caller)]` to the crate attributes to enable
+   = note: `#[warn(ungated_async_fn_track_caller)]` on by default
+
+warning: `#[track_caller]` on async functions is a no-op
+  --> $DIR/panic-track-caller.rs:62:5
+   |
+LL |       #[track_caller]
+   |       ^^^^^^^^^^^^^^^
+LL | /     async fn bar_assoc() {
+LL | |         panic!();
+LL | |     }
+   | |_____- this function will not propagate the caller location
+   |
+   = note: see issue #87417 <https://github.com/rust-lang/rust/issues/87417> for more information
+   = help: add `#![feature(closure_track_caller)]` to the crate attributes to enable
+
+warning: 2 warnings emitted
+
diff --git a/src/test/ui/async-await/track-caller/panic-track-caller.rs b/src/test/ui/async-await/track-caller/panic-track-caller.rs
index 066cf97628f..f45243b0ea6 100644
--- a/src/test/ui/async-await/track-caller/panic-track-caller.rs
+++ b/src/test/ui/async-await/track-caller/panic-track-caller.rs
@@ -1,7 +1,9 @@
 // run-pass
 // edition:2021
+// revisions: feat nofeat
 // needs-unwind
-#![feature(closure_track_caller, async_closure, stmt_expr_attributes)]
+#![feature(async_closure, stmt_expr_attributes)]
+#![cfg_attr(feat, feature(closure_track_caller))]
 
 use std::future::Future;
 use std::panic;
@@ -45,7 +47,7 @@ async fn foo() {
     bar().await
 }
 
-#[track_caller]
+#[track_caller] //[nofeat]~ WARN `#[track_caller]` on async functions is a no-op
 async fn bar_track_caller() {
     panic!()
 }
@@ -57,7 +59,7 @@ async fn foo_track_caller() {
 struct Foo;
 
 impl Foo {
-    #[track_caller]
+    #[track_caller] //[nofeat]~ WARN `#[track_caller]` on async functions is a no-op
     async fn bar_assoc() {
         panic!();
     }
@@ -67,6 +69,9 @@ async fn foo_assoc() {
     Foo::bar_assoc().await
 }
 
+// Since compilation is expected to fail for this fn when using
+// `nofeat`, we test that separately in `async-closure-gate.rs`
+#[cfg(feat)]
 async fn foo_closure() {
     let c = #[track_caller] async || {
         panic!();
@@ -91,8 +96,18 @@ fn panicked_at(f: impl FnOnce() + panic::UnwindSafe) -> u32 {
 }
 
 fn main() {
-    assert_eq!(panicked_at(|| block_on(foo())), 41);
-    assert_eq!(panicked_at(|| block_on(foo_track_caller())), 54);
-    assert_eq!(panicked_at(|| block_on(foo_assoc())), 67);
-    assert_eq!(panicked_at(|| block_on(foo_closure())), 74);
+    assert_eq!(panicked_at(|| block_on(foo())), 43);
+
+    #[cfg(feat)]
+    assert_eq!(panicked_at(|| block_on(foo_track_caller())), 56);
+    #[cfg(nofeat)]
+    assert_eq!(panicked_at(|| block_on(foo_track_caller())), 52);
+
+    #[cfg(feat)]
+    assert_eq!(panicked_at(|| block_on(foo_assoc())), 69);
+    #[cfg(nofeat)]
+    assert_eq!(panicked_at(|| block_on(foo_assoc())), 64);
+
+    #[cfg(feat)]
+    assert_eq!(panicked_at(|| block_on(foo_closure())), 79);
 }