Rollup merge of rust-lang#87554 - sexxi-goose:fix-issue-87426, r=niko…

…matsakis

2229: Discr should be read when PatKind is Range

This PR fixes an issue related to pattern matching in closures when Edition 2021 is enabled.

- If any of the patterns the discr is being matched on is `PatKind::Range` then the discr should be read

r? `@nikomatsakis`

Closes rust-lang#87426

compiler/rustc_typeck/src/expr_use_visitor.rs

@@ -267,12 +267,21 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                                     }
                                 }
                             }
-                            PatKind::Lit(_) => {
-                                // If the PatKind is a Lit then we want
+                            PatKind::Lit(_) | PatKind::Range(..) => {
+                                // If the PatKind is a Lit or a Range then we want
                                 // to borrow discr.
                                 needs_to_be_read = true;
                             }
-                            _ => {}
+                            PatKind::Or(_)
+                            | PatKind::Box(_)
+                            | PatKind::Slice(..)
+                            | PatKind::Ref(..)
+                            | PatKind::Wild => {
+                                // If the PatKind is Or, Box, Slice or Ref, the decision is made later
+                                // as these patterns contains subpatterns
+                                // If the PatKind is Wild, the decision is made based on the other patterns being
+                                // examined
+                            }
                         }
                     }));
                 }

src/test/ui/closures/2229_closure_analysis/issue-87426.rs

@@ -0,0 +1,14 @@
+// run-pass
+// edition:2021
+
+pub fn foo() {
+    let ref_x_ck = 123;
+    let _y = || match ref_x_ck {
+        2_000_000..=3_999_999 => { println!("A")}
+        _ => { println!("B")}
+    };
+}
+
+fn main() {
+    foo();
+}