Auto merge of #89282 - sexxi-goose:fix-88118, r=nikomatsakis

2229: Consume IfLet expr

When using the IfLet guard feature, we can ICE when attempting to resolve PlaceBuilders.
For pattern matching, we currently don't consume the IfLet expression when "visiting" the arms leading us to not "read" all variables and hence not being able to resolve them.

r? `@nikomatsakis`
Closes https://github.com/rust-lang/rust/issues/88118

3 files changed, 38 insertions, 0 deletions

diff --git a/compiler/rustc_typeck/src/expr_use_visitor.rs b/compiler/rustc_typeck/src/expr_use_visitor.rs
index ba70006fe96..b5c4d6ac261 100644
--- a/compiler/rustc_typeck/src/expr_use_visitor.rs
+++ b/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);
diff --git a/src/test/ui/closures/2229_closure_analysis/issue-88118-2.rs b/src/test/ui/closures/2229_closure_analysis/issue-88118-2.rs
new file mode 100644
index 00000000000..0cfb1a55bf2
--- /dev/null
+++ b/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() {}
diff --git a/src/test/ui/closures/2229_closure_analysis/issue-88118-2.stderr b/src/test/ui/closures/2229_closure_analysis/issue-88118-2.stderr
new file mode 100644
index 00000000000..15689023d81
--- /dev/null
+++ b/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
+