Track drop points in generator_interior

This change adds the basic infrastructure for tracking drop ranges in
generator interior analysis, which allows us to exclude dropped types
from the generator type.

Not yet complete, but many of the async/await and generator tests pass.
The main missing piece is tracking branching control flow (e.g. around
an `if` expression). The patch does include support, however, for
multiple yields in th e same block.

Issue #57478

3 files changed, 5 insertions, 69 deletions

diff --git a/src/test/ui/async-await/async-fn-nonsend.rs b/src/test/ui/async-await/async-fn-nonsend.rs
index 845941200fc..4dd36e7f0f0 100644
--- a/src/test/ui/async-await/async-fn-nonsend.rs
+++ b/src/test/ui/async-await/async-fn-nonsend.rs
@@ -18,7 +18,7 @@ async fn fut() {}
 async fn fut_arg<T>(_: T) {}
 
 async fn local_dropped_before_await() {
-    // FIXME: it'd be nice for this to be allowed in a `Send` `async fn`
+    // this is okay now because of the drop
     let x = non_send();
     drop(x);
     fut().await;
@@ -36,7 +36,7 @@ async fn non_send_temporary_in_match() {
 }
 
 async fn non_sync_with_method_call() {
-    // FIXME: it'd be nice for this to work.
+
     let f: &mut std::fmt::Formatter = panic!();
     if non_sync().fmt(f).unwrap() == () {
         fut().await;
@@ -47,9 +47,9 @@ fn assert_send(_: impl Send) {}
 
 pub fn pass_assert() {
     assert_send(local_dropped_before_await());
-    //~^ ERROR future cannot be sent between threads safely
+
     assert_send(non_send_temporary_in_match());
     //~^ ERROR future cannot be sent between threads safely
     assert_send(non_sync_with_method_call());
-    //~^ ERROR future cannot be sent between threads safely
+
 }
diff --git a/src/test/ui/async-await/unresolved_type_param.rs b/src/test/ui/async-await/unresolved_type_param.rs
index 85d868c2703..79c043b701d 100644
--- a/src/test/ui/async-await/unresolved_type_param.rs
+++ b/src/test/ui/async-await/unresolved_type_param.rs
@@ -8,24 +8,8 @@ async fn bar<T>() -> () {}
 async fn foo() {
     bar().await;
     //~^ ERROR type inside `async fn` body must be known in this context
-    //~| ERROR type inside `async fn` body must be known in this context
-    //~| ERROR type inside `async fn` body must be known in this context
-    //~| ERROR type inside `async fn` body must be known in this context
-    //~| ERROR type inside `async fn` body must be known in this context
     //~| NOTE cannot infer type for type parameter `T`
-    //~| NOTE cannot infer type for type parameter `T`
-    //~| NOTE cannot infer type for type parameter `T`
-    //~| NOTE cannot infer type for type parameter `T`
-    //~| NOTE cannot infer type for type parameter `T`
-    //~| NOTE the type is part of the `async fn` body because of this `await`
-    //~| NOTE the type is part of the `async fn` body because of this `await`
     //~| NOTE the type is part of the `async fn` body because of this `await`
-    //~| NOTE the type is part of the `async fn` body because of this `await`
-    //~| NOTE the type is part of the `async fn` body because of this `await`
-    //~| NOTE in this expansion of desugaring of `await`
-    //~| NOTE in this expansion of desugaring of `await`
-    //~| NOTE in this expansion of desugaring of `await`
-    //~| NOTE in this expansion of desugaring of `await`
     //~| NOTE in this expansion of desugaring of `await`
 }
 fn main() {}
diff --git a/src/test/ui/async-await/unresolved_type_param.stderr b/src/test/ui/async-await/unresolved_type_param.stderr
index 8c0ecb8785d..853e53ed69d 100644
--- a/src/test/ui/async-await/unresolved_type_param.stderr
+++ b/src/test/ui/async-await/unresolved_type_param.stderr
@@ -10,54 +10,6 @@ note: the type is part of the `async fn` body because of this `await`
 LL |     bar().await;
    |          ^^^^^^
 
-error[E0698]: type inside `async fn` body must be known in this context
-  --> $DIR/unresolved_type_param.rs:9:5
-   |
-LL |     bar().await;
-   |     ^^^ cannot infer type for type parameter `T` declared on the function `bar`
-   |
-note: the type is part of the `async fn` body because of this `await`
-  --> $DIR/unresolved_type_param.rs:9:10
-   |
-LL |     bar().await;
-   |          ^^^^^^
-
-error[E0698]: type inside `async fn` body must be known in this context
-  --> $DIR/unresolved_type_param.rs:9:5
-   |
-LL |     bar().await;
-   |     ^^^ cannot infer type for type parameter `T` declared on the function `bar`
-   |
-note: the type is part of the `async fn` body because of this `await`
-  --> $DIR/unresolved_type_param.rs:9:10
-   |
-LL |     bar().await;
-   |          ^^^^^^
-
-error[E0698]: type inside `async fn` body must be known in this context
-  --> $DIR/unresolved_type_param.rs:9:5
-   |
-LL |     bar().await;
-   |     ^^^ cannot infer type for type parameter `T` declared on the function `bar`
-   |
-note: the type is part of the `async fn` body because of this `await`
-  --> $DIR/unresolved_type_param.rs:9:10
-   |
-LL |     bar().await;
-   |          ^^^^^^
-
-error[E0698]: type inside `async fn` body must be known in this context
-  --> $DIR/unresolved_type_param.rs:9:5
-   |
-LL |     bar().await;
-   |     ^^^ cannot infer type for type parameter `T` declared on the function `bar`
-   |
-note: the type is part of the `async fn` body because of this `await`
-  --> $DIR/unresolved_type_param.rs:9:10
-   |
-LL |     bar().await;
-   |          ^^^^^^
-
-error: aborting due to 5 previous errors
+error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0698`.