Handle restricting closure origin

Author: arora-aman

compiler/rustc_typeck/src/check/upvar.rs

@@ -206,11 +206,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // If we have an origin, store it.
             if let Some(origin) = delegate.current_origin.clone() {
                 let origin = if self.tcx.features().capture_disjoint_fields {
-                    origin
+                    (origin.0, restrict_capture_precision(origin.1))
                 } else {
-                    // FIXME(project-rfc-2229#31): Once the changes to support reborrowing are
-                    //                             made, make sure we are selecting and restricting
-                    //                             the origin correctly.
                     (origin.0, Place { projections: vec![], ..origin.1 })
                 };
 

src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-array-diagnostics.rs

@@ -0,0 +1,16 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+//~| `#[warn(incomplete_features)]` on by default
+//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
+
+// Test that array access is not stored as part of closure kind origin
+
+fn expect_fn<F: Fn()>(_f: F) {}
+
+fn main() {
+    let s = [format!("s"), format!("s")];
+    let c = || { //~ ERROR expected a closure that implements the `Fn`
+        let [_, _s] = s;
+    };
+    expect_fn(c);
+}

src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-array-diagnostics.stderr

@@ -0,0 +1,23 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/closure-origin-array-diagnostics.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[E0525]: expected a closure that implements the `Fn` trait, but this closure only implements `FnOnce`
+  --> $DIR/closure-origin-array-diagnostics.rs:12:13
+   |
+LL |     let c = || {
+   |             ^^ this closure implements `FnOnce`, not `Fn`
+LL |         let [_, _s] = s;
+   |                       - closure is `FnOnce` because it moves the variable `s` out of its environment
+LL |     };
+LL |     expect_fn(c);
+   |     --------- the requirement to implement `Fn` derives from here
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0525`.