From 9c3bf4de5534846b289de626dd4dc78f7dc7d13c Mon Sep 17 00:00:00 2001
From: Camille GILLOT <gillot.camille@gmail.com>
Date: Tue, 18 Oct 2022 20:53:24 +0000
Subject: [PATCH] Consider patterns in fn params in an `Elided(Infer)` lifetime
 rib.

---
 compiler/rustc_resolve/src/late.rs              | 17 +++++++++++------
 .../lifetimes/elided-lifetime-in-param-pat.rs   | 11 +++++++++++
 2 files changed, 22 insertions(+), 6 deletions(-)
 create mode 100644 src/test/ui/lifetimes/elided-lifetime-in-param-pat.rs

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 776c8ad528c..1675580bd89 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -1853,9 +1853,11 @@ fn resolve_fn_params(
         let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
         for (index, (pat, ty)) in inputs.enumerate() {
             debug!(?pat, ?ty);
-            if let Some(pat) = pat {
-                self.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
-            }
+            self.with_lifetime_rib(LifetimeRibKind::Elided(LifetimeRes::Infer), |this| {
+                if let Some(pat) = pat {
+                    this.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
+                }
+            });
             self.visit_ty(ty);
 
             if let Some(ref candidates) = self.lifetime_elision_candidates {
@@ -2827,10 +2829,13 @@ fn check_trait_item<F>(
 
     fn resolve_params(&mut self, params: &'ast [Param]) {
         let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
-        for Param { pat, ty, .. } in params {
-            self.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
+        self.with_lifetime_rib(LifetimeRibKind::Elided(LifetimeRes::Infer), |this| {
+            for Param { pat, .. } in params {
+                this.resolve_pattern(pat, PatternSource::FnParam, &mut bindings);
+            }
+        });
+        for Param { ty, .. } in params {
             self.visit_ty(ty);
-            debug!("(resolving function / closure) recorded parameter");
         }
     }
 
diff --git a/src/test/ui/lifetimes/elided-lifetime-in-param-pat.rs b/src/test/ui/lifetimes/elided-lifetime-in-param-pat.rs
new file mode 100644
index 00000000000..c1425fa4243
--- /dev/null
+++ b/src/test/ui/lifetimes/elided-lifetime-in-param-pat.rs
@@ -0,0 +1,11 @@
+// check-pass
+
+struct S<T> {
+    _t: T,
+}
+
+fn f(S::<&i8> { .. }: S<&i8>) {}
+
+fn main() {
+    f(S { _t: &42_i8 });
+}