Add initial set of testcases for RFC 2229

Co-authored-by: Dhruv Jauhar <dhruvjhr@gmail.com>

Author: arora-aman

compiler/rustc_typeck/src/check/upvar.rs

@@ -169,6 +169,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
         .consume_body(body);
 
+        log_capture_analysis!(
+            self,
+            closure_def_id,
+            "capture information: {:#?}",
+            delegate.capture_information
+        );
+
         if let Some(closure_substs) = infer_kind {
             // Unify the (as yet unbound) type variable in the closure
             // substs with the kind we inferred.

src/test/ui/closures/2229_closure_analysis/arrays-completely-captured.rs

@@ -0,0 +1,17 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING the feature `capture_disjoint_fields` is incomplete
+#![feature(rustc_attrs)]
+
+// Ensure that capture analysis results in arrays being completely captured.
+fn main() {
+    let mut m = [1, 2, 3, 4, 5];
+
+    let mut c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    || {
+        m[0] += 10;
+        m[1] += 40;
+    };
+
+    c();
+}

src/test/ui/closures/2229_closure_analysis/arrays-completely-captured.stderr

@@ -0,0 +1,21 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/arrays-completely-captured.rs:9:17
+   |
+LL |     let mut 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/arrays-completely-captured.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: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/arrays-completely-captured.stdout

@@ -0,0 +1,20 @@
+For closure=DefId(0:4 ~ arrays_completely_captured[317d]::main::{closure#0}): Using new-style capture analysis
+For closure=DefId(0:4 ~ arrays_completely_captured[317d]::main::{closure#0}): capture information: {
+    Place {
+        base_ty: [i32; 5],
+        base: Upvar(
+            UpvarId(HirId { owner: DefId(0:3 ~ arrays_completely_captured[317d]::main), local_id: 1 };`m`;DefId(0:4 ~ arrays_completely_captured[317d]::main::{closure#0})),
+        ),
+        projections: [],
+    }: CaptureInfo {
+        expr_id: Some(
+            HirId {
+                owner: DefId(0:3 ~ arrays_completely_captured[317d]::main),
+                local_id: 12,
+            },
+        ),
+        capture_kind: ByRef(
+            UpvarBorrow(MutBorrow, '_#6r),
+        ),
+    },
+}

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-struct.rs

@@ -0,0 +1,26 @@
+// FIXME(arora-aman) add run-pass once 2229 is implemented
+
+#![feature(capture_disjoint_fields)]
+//~^ WARNING the feature `capture_disjoint_fields` is incomplete
+#![feature(rustc_attrs)]
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    let mut p = Point { x: 10, y: 10 };
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    || {
+        println!("{}", p.x);
+    };
+
+    // `c` should only capture `p.x`, therefore mutating `p.y` is allowed.
+    let py = &mut p.y;
+
+    c();
+    *py = 20;
+}

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-struct.stderr

@@ -0,0 +1,21 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-disjoint-field-struct.rs:15:13
+   |
+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-disjoint-field-struct.rs:3:12
+   |
+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: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-struct.stdout

@@ -0,0 +1,28 @@
+For closure=DefId(0:7 ~ capture_disjoint_field_struct[317d]::main::{closure#0}): Using new-style capture analysis
+For closure=DefId(0:7 ~ capture_disjoint_field_struct[317d]::main::{closure#0}): capture information: {
+    Place {
+        base_ty: Point,
+        base: Upvar(
+            UpvarId(HirId { owner: DefId(0:6 ~ capture_disjoint_field_struct[317d]::main), local_id: 1 };`p`;DefId(0:7 ~ capture_disjoint_field_struct[317d]::main::{closure#0})),
+        ),
+        projections: [
+            Projection {
+                ty: i32,
+                kind: Field(
+                    0,
+                    0,
+                ),
+            },
+        ],
+    }: CaptureInfo {
+        expr_id: Some(
+            HirId {
+                owner: DefId(0:6 ~ capture_disjoint_field_struct[317d]::main),
+                local_id: 31,
+            },
+        ),
+        capture_kind: ByRef(
+            UpvarBorrow(ImmBorrow, '_#35r),
+        ),
+    },
+}

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-tuple.rs

@@ -0,0 +1,21 @@
+// FIXME(arora-aman) add run-pass once 2229 is implemented
+
+#![feature(capture_disjoint_fields)]
+//~^ WARNING the feature `capture_disjoint_fields` is incomplete
+#![feature(rustc_attrs)]
+
+fn main() {
+    let mut t = (10, 10);
+
+    let c = #[rustc_capture_analysis]
+    //~^ ERROR: attributes on expressions are experimental
+    || {
+        println!("{}", t.0);
+    };
+
+    // `c` only captures t.0, therefore mutating t.1 is allowed.
+    let t1 = &mut t.1;
+
+    c();
+    *t1 = 20;
+}

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-tuple.stderr

@@ -0,0 +1,21 @@
+error[E0658]: attributes on expressions are experimental
+  --> $DIR/capture-disjoint-field-tuple.rs:8:13
+   |
+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-disjoint-field-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: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/closures/2229_closure_analysis/capture-disjoint-field-tuple.stdout

@@ -0,0 +1,28 @@
+For closure=DefId(0:4 ~ capture_disjoint_field_tuple[317d]::main::{closure#0}): Using new-style capture analysis
+For closure=DefId(0:4 ~ capture_disjoint_field_tuple[317d]::main::{closure#0}): capture information: {
+    Place {
+        base_ty: (i32, i32),
+        base: Upvar(
+            UpvarId(HirId { owner: DefId(0:3 ~ capture_disjoint_field_tuple[317d]::main), local_id: 1 };`t`;DefId(0:4 ~ capture_disjoint_field_tuple[317d]::main::{closure#0})),
+        ),
+        projections: [
+            Projection {
+                ty: i32,
+                kind: Field(
+                    0,
+                    0,
+                ),
+            },
+        ],
+    }: CaptureInfo {
+        expr_id: Some(
+            HirId {
+                owner: DefId(0:3 ~ capture_disjoint_field_tuple[317d]::main),
+                local_id: 28,
+            },
+        ),
+        capture_kind: ByRef(
+            UpvarBorrow(ImmBorrow, '_#35r),
+        ),
+    },
+}