Don't create cycles by normalizing opaques defined in the body we're …

…checking

(cherry picked from commit 197f6d8)

compiler/rustc_mir_transform/src/lint_tail_expr_drop_order.rs

@@ -351,14 +351,19 @@ pub(crate) fn run_lint<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId, body: &Body<
     {
         return;
     }
+
+    // FIXME(typing_env): This should be able to reveal the opaques local to the
+    // body using the typeck results.
+    let typing_env = ty::TypingEnv::non_body_analysis(tcx, def_id);
+
     // ## About BIDs in blocks ##
     // Track the set of blocks that contain a backwards-incompatible drop (BID)
     // and, for each block, the vector of locations.
     //
     // We group them per-block because they tend to scheduled in the same drop ladder block.
     let mut bid_per_block = IndexMap::default();
     let mut bid_places = UnordSet::new();
-    let typing_env = ty::TypingEnv::post_analysis(tcx, def_id);
+
     let mut ty_dropped_components = UnordMap::default();
     for (block, data) in body.basic_blocks.iter_enumerated() {
         for (statement_index, stmt) in data.statements.iter().enumerate() {

tests/ui/drop/lint-tail-expr-drop-order.rs

@@ -17,7 +17,6 @@ impl Drop for LoudDropper {
     //~| NOTE: `#1` invokes this custom destructor
     //~| NOTE: `x` invokes this custom destructor
     //~| NOTE: `#1` invokes this custom destructor
-    //~| NOTE: `future` invokes this custom destructor
     //~| NOTE: `_x` invokes this custom destructor
     //~| NOTE: `#1` invokes this custom destructor
     fn drop(&mut self) {

tests/ui/drop/lint-tail-expr-drop-order.stderr

@@ -1,5 +1,5 @@
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:41:15
+  --> $DIR/lint-tail-expr-drop-order.rs:40:15
    |
 LL |     let x = LoudDropper;
    |         -
@@ -40,7 +40,7 @@ LL | #![deny(tail_expr_drop_order)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:66:19
+  --> $DIR/lint-tail-expr-drop-order.rs:65:19
    |
 LL |         let x = LoudDropper;
    |             -
@@ -76,7 +76,7 @@ LL | | }
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:93:7
+  --> $DIR/lint-tail-expr-drop-order.rs:92:7
    |
 LL |     let x = LoudDropper;
    |         -
@@ -112,7 +112,7 @@ LL | | }
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:146:5
+  --> $DIR/lint-tail-expr-drop-order.rs:145:5
    |
 LL |     let future = f();
    |         ------
@@ -136,19 +136,12 @@ note: `#1` invokes this custom destructor
    |
 LL | / impl Drop for LoudDropper {
 ...  |
-LL | | }
-   | |_^
-note: `future` invokes this custom destructor
-  --> $DIR/lint-tail-expr-drop-order.rs:10:1
-   |
-LL | / impl Drop for LoudDropper {
-...  |
 LL | | }
    | |_^
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:163:14
+  --> $DIR/lint-tail-expr-drop-order.rs:162:14
    |
 LL |     let x = T::default();
    |         -
@@ -170,7 +163,7 @@ LL | }
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:177:5
+  --> $DIR/lint-tail-expr-drop-order.rs:176:5
    |
 LL |     let x: Result<LoudDropper, ()> = Ok(LoudDropper);
    |         -
@@ -206,7 +199,7 @@ LL | | }
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:221:5
+  --> $DIR/lint-tail-expr-drop-order.rs:220:5
    |
 LL |     let x = LoudDropper2;
    |         -
@@ -226,7 +219,7 @@ LL | }
    = warning: this changes meaning in Rust 2024
    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html>
 note: `#1` invokes this custom destructor
-  --> $DIR/lint-tail-expr-drop-order.rs:194:5
+  --> $DIR/lint-tail-expr-drop-order.rs:193:5
    |
 LL | /     impl Drop for LoudDropper3 {
 LL | |
@@ -236,7 +229,7 @@ LL | |         }
 LL | |     }
    | |_____^
 note: `x` invokes this custom destructor
-  --> $DIR/lint-tail-expr-drop-order.rs:206:5
+  --> $DIR/lint-tail-expr-drop-order.rs:205:5
    |
 LL | /     impl Drop for LoudDropper2 {
 LL | |
@@ -248,7 +241,7 @@ LL | |     }
    = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages
 
 error: relative drop order changing in Rust 2024
-  --> $DIR/lint-tail-expr-drop-order.rs:234:13
+  --> $DIR/lint-tail-expr-drop-order.rs:233:13
    |
 LL |             LoudDropper.get()
    |             ^^^^^^^^^^^

tests/ui/drop/tail_expr_drop_order-on-coroutine-unwind.stderr

@@ -4,10 +4,14 @@ error: relative drop order changing in Rust 2024
 LL |         match func().await {
    |               ^^^^^^^-----
    |               |      |
+   |               |      this value will be stored in a temporary; let us call it `#3`
+   |               |      up until Edition 2021 `#3` is dropped last but will be dropped earlier in Edition 2024
    |               |      this value will be stored in a temporary; let us call it `#1`
    |               |      `#1` will be dropped later as of Edition 2024
    |               this value will be stored in a temporary; let us call it `#2`
    |               up until Edition 2021 `#2` is dropped last but will be dropped earlier in Edition 2024
+   |               `__awaitee` calls a custom destructor
+   |               `__awaitee` will be dropped later as of Edition 2024
 ...
 LL |             Err(e) => {}
    |                 -

tests/ui/drop/tail_expr_drop_order-on-recursive-boxed-fut.rs

@@ -0,0 +1,13 @@
+//@ edition: 2021
+//@ check-pass
+
+// Make sure we don't cycle error when normalizing types for tail expr drop order lint.
+
+#![deny(tail_expr_drop_order)]
+
+async fn test() -> Result<(), Box<dyn std::error::Error>> {
+    Box::pin(test()).await?;
+    Ok(())
+}
+
+fn main() {}