Rollup merge of #81062 - sexxi-goose:precise_capture_diagnostics, r=nikomatsakis

Improve diagnostics for Precise Capture

This is just the capture analysis part and borrow checker logging will updated as part of rust-lang/project-rfc-2229#8

Closes rust-lang/project-rfc-2229#22

src/test/ui/closures/2229_closure_analysis/capture-analysis-1.rs

@@ -0,0 +1,35 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    let p = Point { x: 10, y: 10 };
+    let q = Point { x: 10, y: 10 };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ First Pass analysis includes:
+    //~| Min Capture analysis includes:
+        println!("{:?}", p);
+        //~^ NOTE: Capturing p[] -> ImmBorrow
+        //~| NOTE: Min Capture p[] -> ImmBorrow
+        println!("{:?}", p.x);
+        //~^ NOTE: Capturing p[(0, 0)] -> ImmBorrow
+
+        println!("{:?}", q.x);
+        //~^ NOTE: Capturing q[(0, 0)] -> ImmBorrow
+        println!("{:?}", q);
+        //~^ NOTE: Capturing q[] -> ImmBorrow
+        //~| NOTE: Min Capture q[] -> ImmBorrow
+    };
+}

src/test/ui/closures/2229_closure_analysis/capture-analysis-1.stderr

@@ -0,0 +1,77 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-analysis-1.rs:17:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/capture-analysis-1.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/capture-analysis-1.rs:20:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         println!("{:?}", p);
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing p[] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:23:26
+   |
+LL |         println!("{:?}", p);
+   |                          ^
+note: Capturing p[(0, 0)] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:26:26
+   |
+LL |         println!("{:?}", p.x);
+   |                          ^^^
+note: Capturing q[(0, 0)] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:29:26
+   |
+LL |         println!("{:?}", q.x);
+   |                          ^^^
+note: Capturing q[] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:31:26
+   |
+LL |         println!("{:?}", q);
+   |                          ^
+
+error: Min Capture analysis includes:
+  --> $DIR/capture-analysis-1.rs:20:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         println!("{:?}", p);
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture p[] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:23:26
+   |
+LL |         println!("{:?}", p);
+   |                          ^
+note: Min Capture q[] -> ImmBorrow
+  --> $DIR/capture-analysis-1.rs:31:26
+   |
+LL |         println!("{:?}", q);
+   |                          ^
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/capture-analysis-2.rs

@@ -0,0 +1,30 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+
+#[derive(Debug)]
+struct Point {
+    x: String,
+    y: i32,
+}
+
+fn main() {
+    let mut p = Point { x: String::new(), y: 10 };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ First Pass analysis includes:
+    //~| Min Capture analysis includes:
+        let _x = p.x;
+        //~^ NOTE: Capturing p[(0, 0)] -> ByValue
+        //~| NOTE: p[] captured as ByValue here
+        println!("{:?}", p);
+        //~^ NOTE: Capturing p[] -> ImmBorrow
+        //~| NOTE: Min Capture p[] -> ByValue
+        //~| NOTE: p[] used here
+    };
+}

src/test/ui/closures/2229_closure_analysis/capture-analysis-2.stderr

@@ -0,0 +1,65 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-analysis-2.rs:16:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/capture-analysis-2.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/capture-analysis-2.rs:19:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = p.x;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing p[(0, 0)] -> ByValue
+  --> $DIR/capture-analysis-2.rs:22:18
+   |
+LL |         let _x = p.x;
+   |                  ^^^
+note: Capturing p[] -> ImmBorrow
+  --> $DIR/capture-analysis-2.rs:25:26
+   |
+LL |         println!("{:?}", p);
+   |                          ^
+
+error: Min Capture analysis includes:
+  --> $DIR/capture-analysis-2.rs:19:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = p.x;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture p[] -> ByValue
+  --> $DIR/capture-analysis-2.rs:22:18
+   |
+LL |         let _x = p.x;
+   |                  ^^^ p[] captured as ByValue here
+...
+LL |         println!("{:?}", p);
+   |                          ^ p[] used here
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/capture-analysis-3.rs

@@ -0,0 +1,35 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+
+#[derive(Debug)]
+struct Child {
+    c: String,
+    d: String,
+}
+
+#[derive(Debug)]
+struct Parent {
+    b: Child,
+}
+
+fn main() {
+    let mut a = Parent { b: Child {c: String::new(), d: String::new()} };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ First Pass analysis includes:
+    //~| Min Capture analysis includes:
+        let _x = a.b.c;
+        //~^ NOTE: Capturing a[(0, 0),(0, 0)] -> ByValue
+        //~| NOTE: a[(0, 0)] captured as ByValue here
+        println!("{:?}", a.b);
+        //~^ NOTE: Capturing a[(0, 0)] -> ImmBorrow
+        //~| NOTE: Min Capture a[(0, 0)] -> ByValue
+        //~| NOTE: a[(0, 0)] used here
+    };
+}

src/test/ui/closures/2229_closure_analysis/capture-analysis-3.stderr

@@ -0,0 +1,65 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-analysis-3.rs:21:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/capture-analysis-3.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/capture-analysis-3.rs:24:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = a.b.c;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing a[(0, 0),(0, 0)] -> ByValue
+  --> $DIR/capture-analysis-3.rs:27:18
+   |
+LL |         let _x = a.b.c;
+   |                  ^^^^^
+note: Capturing a[(0, 0)] -> ImmBorrow
+  --> $DIR/capture-analysis-3.rs:30:26
+   |
+LL |         println!("{:?}", a.b);
+   |                          ^^^
+
+error: Min Capture analysis includes:
+  --> $DIR/capture-analysis-3.rs:24:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = a.b.c;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture a[(0, 0)] -> ByValue
+  --> $DIR/capture-analysis-3.rs:27:18
+   |
+LL |         let _x = a.b.c;
+   |                  ^^^^^ a[(0, 0)] captured as ByValue here
+...
+LL |         println!("{:?}", a.b);
+   |                          ^^^ a[(0, 0)] used here
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/capture-analysis-4.rs

@@ -0,0 +1,33 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+
+#[derive(Debug)]
+struct Child {
+    c: String,
+    d: String,
+}
+
+#[derive(Debug)]
+struct Parent {
+    b: Child,
+}
+
+fn main() {
+    let mut a = Parent { b: Child {c: String::new(), d: String::new()} };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ First Pass analysis includes:
+    //~| Min Capture analysis includes:
+        let _x = a.b;
+        //~^ NOTE: Capturing a[(0, 0)] -> ByValue
+        //~| NOTE: Min Capture a[(0, 0)] -> ByValue
+        println!("{:?}", a.b.c);
+        //~^ NOTE: Capturing a[(0, 0),(0, 0)] -> ImmBorrow
+    };
+}

src/test/ui/closures/2229_closure_analysis/capture-analysis-4.stderr

@@ -0,0 +1,62 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-analysis-4.rs:21:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/capture-analysis-4.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/capture-analysis-4.rs:24:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = a.b;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing a[(0, 0)] -> ByValue
+  --> $DIR/capture-analysis-4.rs:27:18
+   |
+LL |         let _x = a.b;
+   |                  ^^^
+note: Capturing a[(0, 0),(0, 0)] -> ImmBorrow
+  --> $DIR/capture-analysis-4.rs:30:26
+   |
+LL |         println!("{:?}", a.b.c);
+   |                          ^^^^^
+
+error: Min Capture analysis includes:
+  --> $DIR/capture-analysis-4.rs:24:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let _x = a.b;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture a[(0, 0)] -> ByValue
+  --> $DIR/capture-analysis-4.rs:27:18
+   |
+LL |         let _x = a.b;
+   |                  ^^^
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/deep-multilevel-struct.rs

@@ -0,0 +1,52 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+#![allow(unused)]
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+#[derive(Debug)]
+struct Line {
+    p: Point,
+    q: Point
+}
+#[derive(Debug)]
+struct Plane {
+    a: Line,
+    b: Line,
+}
+
+fn main() {
+    let mut p = Plane {
+        a: Line {
+            p: Point { x: 1,y: 2 },
+            q: Point { x: 3,y: 4 },
+        },
+        b: Line {
+            p: Point { x: 1,y: 2 },
+            q: Point { x: 3,y: 4 },
+        }
+    };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ ERROR: First Pass analysis includes:
+    //~| ERROR: Min Capture analysis includes:
+        let x = &p.a.p.x;
+        //~^ NOTE: Capturing p[(0, 0),(0, 0),(0, 0)] -> ImmBorrow
+        p.b.q.y = 9;
+        //~^ NOTE: Capturing p[(1, 0),(1, 0),(1, 0)] -> MutBorrow
+        //~| NOTE: p[] captured as MutBorrow here
+        println!("{:?}", p);
+        //~^ NOTE: Capturing p[] -> ImmBorrow
+        //~| NOTE: Min Capture p[] -> MutBorrow
+        //~| NOTE: p[] used here
+    };
+}

src/test/ui/closures/2229_closure_analysis/deep-multilevel-struct.stderr

@@ -0,0 +1,70 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/deep-multilevel-struct.rs:36:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/deep-multilevel-struct.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/deep-multilevel-struct.rs:39:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let x = &p.a.p.x;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing p[(0, 0),(0, 0),(0, 0)] -> ImmBorrow
+  --> $DIR/deep-multilevel-struct.rs:42:18
+   |
+LL |         let x = &p.a.p.x;
+   |                  ^^^^^^^
+note: Capturing p[(1, 0),(1, 0),(1, 0)] -> MutBorrow
+  --> $DIR/deep-multilevel-struct.rs:44:9
+   |
+LL |         p.b.q.y = 9;
+   |         ^^^^^^^
+note: Capturing p[] -> ImmBorrow
+  --> $DIR/deep-multilevel-struct.rs:47:26
+   |
+LL |         println!("{:?}", p);
+   |                          ^
+
+error: Min Capture analysis includes:
+  --> $DIR/deep-multilevel-struct.rs:39:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let x = &p.a.p.x;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture p[] -> MutBorrow
+  --> $DIR/deep-multilevel-struct.rs:44:9
+   |
+LL |         p.b.q.y = 9;
+   |         ^^^^^^^ p[] captured as MutBorrow here
+...
+LL |         println!("{:?}", p);
+   |                          ^ p[] used here
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/deep-multilevel-tuple.rs

@@ -0,0 +1,27 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| NOTE: `#[warn(incomplete_features)]` on by default
+//~| NOTE: see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+#![feature(rustc_attrs)]
+#![allow(unused)]
+
+fn main() {
+    let mut t = (((1,2),(3,4)),((5,6),(7,8)));
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    //~| NOTE: see issue #15701 <https://github.com/rust-lang/rust/issues/15701>
+    || {
+    //~^ ERROR: First Pass analysis includes:
+    //~| ERROR: Min Capture analysis includes:
+        let x = &t.0.0.0;
+        //~^ NOTE: Capturing t[(0, 0),(0, 0),(0, 0)] -> ImmBorrow
+        t.1.1.1 = 9;
+        //~^ NOTE: Capturing t[(1, 0),(1, 0),(1, 0)] -> MutBorrow
+        //~| NOTE: t[] captured as MutBorrow here
+        println!("{:?}", t);
+        //~^ NOTE: Min Capture t[] -> MutBorrow
+        //~| NOTE: Capturing t[] -> ImmBorrow
+        //~| NOTE: t[] used here
+    };
+}

src/test/ui/closures/2229_closure_analysis/deep-multilevel-tuple.stderr

@@ -0,0 +1,70 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/deep-multilevel-tuple.rs:11:13
+   |
+LL |     let c = #[rustc_capture_analysis]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #15701 <https://github.com/rust-lang/rust/issues/15701> for more information
+   = help: add `#![feature(stmt_expr_attributes)]` to the crate attributes to enable
+
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/deep-multilevel-tuple.rs:1:12
+   |
+LL | #![feature(capture_disjoint_fields)]
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+   = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
+
+error: First Pass analysis includes:
+  --> $DIR/deep-multilevel-tuple.rs:14:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let x = &t.0.0.0;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Capturing t[(0, 0),(0, 0),(0, 0)] -> ImmBorrow
+  --> $DIR/deep-multilevel-tuple.rs:17:18
+   |
+LL |         let x = &t.0.0.0;
+   |                  ^^^^^^^
+note: Capturing t[(1, 0),(1, 0),(1, 0)] -> MutBorrow
+  --> $DIR/deep-multilevel-tuple.rs:19:9
+   |
+LL |         t.1.1.1 = 9;
+   |         ^^^^^^^
+note: Capturing t[] -> ImmBorrow
+  --> $DIR/deep-multilevel-tuple.rs:22:26
+   |
+LL |         println!("{:?}", t);
+   |                          ^
+
+error: Min Capture analysis includes:
+  --> $DIR/deep-multilevel-tuple.rs:14:5
+   |
+LL | /     || {
+LL | |
+LL | |
+LL | |         let x = &t.0.0.0;
+...  |
+LL | |
+LL | |     };
+   | |_____^
+   |
+note: Min Capture t[] -> MutBorrow
+  --> $DIR/deep-multilevel-tuple.rs:19:9
+   |
+LL |         t.1.1.1 = 9;
+   |         ^^^^^^^ t[] captured as MutBorrow here
+...
+LL |         println!("{:?}", t);
+   |                          ^ t[] used here
+
+error: aborting due to 3 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/simple-struct-min-capture.rs

@@ -32,9 +32,11 @@ fn main() {
     //~| ERROR: Min Capture analysis includes:
         p.x += 10;
         //~^ NOTE: Capturing p[(0, 0)] -> MutBorrow
-        //~| NOTE: Min Capture p[] -> MutBorrow
+        //~| NOTE: p[] captured as MutBorrow here
         println!("{:?}", p);
         //~^ NOTE: Capturing p[] -> ImmBorrow
+        //~| NOTE: Min Capture p[] -> MutBorrow
+        //~| NOTE: p[] used here
     };
 
     c();

src/test/ui/closures/2229_closure_analysis/simple-struct-min-capture.stderr

@@ -55,7 +55,10 @@ note: Min Capture p[] -> MutBorrow
   --> $DIR/simple-struct-min-capture.rs:33:9
    |
 LL |         p.x += 10;
-   |         ^^^
+   |         ^^^ p[] captured as MutBorrow here
+...
+LL |         println!("{:?}", p);
+   |                          ^ p[] used here
 
 error: aborting due to 3 previous errors; 1 warning emitted