borrowck typeck children together with their parent

4 files changed, 92 insertions, 26 deletions

diff --git a/tests/ui/pattern/non-structural-match-types-cycle-err.rs b/tests/ui/pattern/non-structural-match-types-cycle-err.rs
new file mode 100644
index 00000000000..a8e494c35b0
--- /dev/null
+++ b/tests/ui/pattern/non-structural-match-types-cycle-err.rs
@@ -0,0 +1,24 @@
+//@ edition:2021
+
+struct AnyOption<T>(T);
+impl<T> AnyOption<T> {
+    const NONE: Option<T> = None;
+}
+
+// This is an unfortunate side-effect of borrowchecking nested items
+// together with their parent. Evaluating the `AnyOption::<_>::NONE`
+// pattern for exhaustiveness checking relies on the layout of the
+// async block. This layout relies on `optimized_mir` of the nested
+// item which is now borrowck'd together with its parent. As
+// borrowck of the parent requires us to have already lowered the match,
+// this is a query cycle.
+
+fn uwu() {}
+fn defines() {
+    match Some(async {}) {
+        AnyOption::<_>::NONE => {}
+        //~^ ERROR cycle detected when building THIR for `defines`
+        _ => {}
+    }
+}
+fn main() {}
diff --git a/tests/ui/pattern/non-structural-match-types-cycle-err.stderr b/tests/ui/pattern/non-structural-match-types-cycle-err.stderr
new file mode 100644
index 00000000000..2f4ac63fc57
--- /dev/null
+++ b/tests/ui/pattern/non-structural-match-types-cycle-err.stderr
@@ -0,0 +1,64 @@
+error[E0391]: cycle detected when building THIR for `defines`
+  --> $DIR/non-structural-match-types-cycle-err.rs:19:9
+   |
+LL |         AnyOption::<_>::NONE => {}
+   |         ^^^^^^^^^^^^^^^^^^^^
+   |
+note: ...which requires evaluating type-level constant...
+  --> $DIR/non-structural-match-types-cycle-err.rs:5:5
+   |
+LL |     const NONE: Option<T> = None;
+   |     ^^^^^^^^^^^^^^^^^^^^^
+note: ...which requires const-evaluating + checking `<impl at $DIR/non-structural-match-types-cycle-err.rs:4:1: 4:21>::NONE`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:5:5
+   |
+LL |     const NONE: Option<T> = None;
+   |     ^^^^^^^^^^^^^^^^^^^^^
+   = note: ...which requires computing layout of `core::option::Option<{async block@$DIR/non-structural-match-types-cycle-err.rs:18:16: 18:21}>`...
+   = note: ...which requires computing layout of `{async block@$DIR/non-structural-match-types-cycle-err.rs:18:16: 18:21}`...
+note: ...which requires optimizing MIR for `defines::{closure#0}`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:18:16
+   |
+LL |     match Some(async {}) {
+   |                ^^^^^
+note: ...which requires elaborating drops for `defines::{closure#0}`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:18:16
+   |
+LL |     match Some(async {}) {
+   |                ^^^^^
+note: ...which requires borrow-checking `defines`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+note: ...which requires promoting constants in MIR for `defines`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+note: ...which requires checking if `defines` contains FFI-unwind calls...
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+note: ...which requires building MIR for `defines`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+note: ...which requires match-checking `defines`...
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+   = note: ...which again requires building THIR for `defines`, completing the cycle
+note: cycle used when unsafety-checking `defines`
+  --> $DIR/non-structural-match-types-cycle-err.rs:17:1
+   |
+LL | fn defines() {
+   | ^^^^^^^^^^^^
+   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/pattern/non-structural-match-types.rs b/tests/ui/pattern/non-structural-match-types.rs
index 5869767c936..a5ff7fcdb5e 100644
--- a/tests/ui/pattern/non-structural-match-types.rs
+++ b/tests/ui/pattern/non-structural-match-types.rs
@@ -1,6 +1,4 @@
 //@ edition:2021
-#![feature(const_async_blocks)]
-
 struct AnyOption<T>(T);
 impl<T> AnyOption<T> {
     const NONE: Option<T> = None;
@@ -19,11 +17,5 @@ fn defines() {
         //~^ ERROR constant of non-structural type
         _ => {}
     }
-
-    match Some(async {}) {
-        AnyOption::<_>::NONE => {}
-        //~^ ERROR constant of non-structural type
-        _ => {}
-    }
 }
 fn main() {}
diff --git a/tests/ui/pattern/non-structural-match-types.stderr b/tests/ui/pattern/non-structural-match-types.stderr
index da675a9f3ff..3b74ffe7cb7 100644
--- a/tests/ui/pattern/non-structural-match-types.stderr
+++ b/tests/ui/pattern/non-structural-match-types.stderr
@@ -1,5 +1,5 @@
 error: constant of non-structural type `Option<fn() {uwu}>` in a pattern
-  --> $DIR/non-structural-match-types.rs:12:9
+  --> $DIR/non-structural-match-types.rs:10:9
    |
 LL | impl<T> AnyOption<T> {
    | --------------------
@@ -11,8 +11,8 @@ LL |         AnyOption::<_>::NONE => {}
    |
    = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details
 
-error: constant of non-structural type `Option<{closure@$DIR/non-structural-match-types.rs:17:16: 17:18}>` in a pattern
-  --> $DIR/non-structural-match-types.rs:18:9
+error: constant of non-structural type `Option<{closure@$DIR/non-structural-match-types.rs:15:16: 15:18}>` in a pattern
+  --> $DIR/non-structural-match-types.rs:16:9
    |
 LL | impl<T> AnyOption<T> {
    | --------------------
@@ -24,19 +24,5 @@ LL |         AnyOption::<_>::NONE => {}
    |
    = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details
 
-error: constant of non-structural type `Option<{async block@$DIR/non-structural-match-types.rs:23:16: 23:21}>` in a pattern
-  --> $DIR/non-structural-match-types.rs:24:9
-   |
-LL | impl<T> AnyOption<T> {
-   | --------------------
-LL |     const NONE: Option<T> = None;
-   |     --------------------- constant defined here
-...
-LL |         AnyOption::<_>::NONE => {}
-   |         ^^^^^^^^^^^^^^^^^^^^ constant of non-structural type
-   |
-   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details
-   = note: `ResumeTy` must be annotated with `#[derive(PartialEq)]` to be usable in patterns
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors