2229: Consume IfLet expr

compiler/rustc_typeck/src/expr_use_visitor.rs

@@ -619,6 +619,8 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
 
         if let Some(hir::Guard::If(ref e)) = arm.guard {
             self.consume_expr(e)
+        } else if let Some(hir::Guard::IfLet(_, ref e)) = arm.guard {
+            self.consume_expr(e)
         }
 
         self.consume_expr(&arm.body);

src/test/ui/closures/2229_closure_analysis/issue-88118-2.rs

@@ -0,0 +1,24 @@
+// edition:2021
+// run-pass
+#![feature(if_let_guard)]
+#[allow(unused_must_use)]
+#[allow(dead_code)]
+
+fn print_error_count(registry: &Registry) {
+    |x: &Registry| {
+        match &x {
+            Registry if let _ = registry.try_find_description() => { }
+            //~^ WARNING: irrefutable `if let` guard pattern
+            _ => {}
+        }
+    };
+}
+
+struct Registry;
+impl Registry {
+    pub fn try_find_description(&self) {
+        unimplemented!()
+    }
+}
+
+fn main() {}

src/test/ui/closures/2229_closure_analysis/issue-88118-2.stderr

@@ -0,0 +1,12 @@
+warning: irrefutable `if let` guard pattern
+  --> $DIR/issue-88118-2.rs:10:29
+   |
+LL |             Registry if let _ = registry.try_find_description() => { }
+   |                             ^
+   |
+   = note: `#[warn(irrefutable_let_patterns)]` on by default
+   = note: this pattern will always match, so the guard is useless
+   = help: consider removing the guard and adding a `let` inside the match arm
+
+warning: 1 warning emitted
+