Edition 2021 enables disjoint capture

compiler/rustc_typeck/src/check/upvar.rs

@@ -177,7 +177,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
  // We now fake capture information for all variables that are mentioned within the closure
  // We do this after handling migrations so that min_captures computes before
- if !self.tcx.features().capture_disjoint_fields {
+ if !enable_precise_capture(self.tcx, span) {
  let mut capture_information: InferredCaptureInformation<'tcx> = Default::default();
 
  if let Some(upvars) = self.tcx.upvars_mentioned(closure_def_id) {
@@ -212,7 +212,7 @@ 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 {
+ let origin = if enable_precise_capture(self.tcx, span) {
  (origin.0, restrict_capture_precision(origin.1))
  } else {
  (origin.0, Place { projections: vec![], ..origin.1 })
@@ -1924,3 +1924,13 @@ fn determine_place_ancestry_relation(
  PlaceAncestryRelation::Divergent
  }
 }
+
+/// Precise capture is enabled if the feature gate `capture_disjoint_fields` is enabled or if
+/// user is using Rust Edition 2021 or higher.
+///
+/// `span` is the span of the closure.
+fn enable_precise_capture(tcx: TyCtxt<'_>, span: Span) -> bool {
+ // We use span here to ensure that if the closure was generated by a macro with a different
+ // edition.
+ tcx.features().capture_disjoint_fields || span.rust_2021()
+}

src/test/ui/closures/2229_closure_analysis/run_pass/edition.rs

@@ -0,0 +1,23 @@
+// edition:2021
+// run-pass
+
+// Test that edition 2021 enables disjoint capture by default.
+
+struct Point {
+ x: i32,
+ y: i32,
+}
+
+fn main() {
+ let mut p = Point { x: 10, y: 10 };
+
+ let c = || {
+ println!("{}", p.x);
+ };
+
+ // `c` should only capture `p.x`, therefore mutating `p.y` is allowed.
+ let py = &mut p.y;
+
+ c();
+ *py = 20;
+}