Auto merge of #113396 - lenko-d:dont_ICE_when_no_bound_vars_for_lifetime_binders, r=compiler-errors

Don't ICE when no bound vars found while doing closure hir type check

The problem was that we were not visiting the const generic default argument in a bound where predicate when the HIR gets traversed in hir_analysis -> collect -> resolve_bound_vars.

Fixes [112574](#112574)

Author: bors

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -856,22 +856,6 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
         let scope = Scope::TraitRefBoundary { s: self.scope };
         self.with(scope, |this| {
             walk_list!(this, visit_generic_param, generics.params);
-            for param in generics.params {
-                match param.kind {
-                    GenericParamKind::Lifetime { .. } => {}
-                    GenericParamKind::Type { default, .. } => {
-                        if let Some(ty) = default {
-                            this.visit_ty(ty);
-                        }
-                    }
-                    GenericParamKind::Const { ty, default } => {
-                        this.visit_ty(ty);
-                        if let Some(default) = default {
-                            this.visit_body(this.tcx.hir().body(default.body));
-                        }
-                    }
-                }
-            }
             walk_list!(this, visit_where_predicate, generics.predicates);
         })
     }
@@ -1000,6 +984,21 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                 // like implicit `?Sized` or const-param-has-ty predicates.
             }
         }
+
+        match p.kind {
+            GenericParamKind::Lifetime { .. } => {}
+            GenericParamKind::Type { default, .. } => {
+                if let Some(ty) = default {
+                    self.visit_ty(ty);
+                }
+            }
+            GenericParamKind::Const { ty, default } => {
+                self.visit_ty(ty);
+                if let Some(default) = default {
+                    self.visit_body(self.tcx.hir().body(default.body));
+                }
+            }
+        }
     }
 }
 

tests/ui/closures/issue-112547.rs

@@ -0,0 +1,15 @@
+#![feature(non_lifetime_binders)]
+        //~^ WARNING the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+
+pub fn bar()
+where
+    for<const N: usize = {
+    (||1usize)()
+}> V: IntoIterator
+//~^ ERROR cannot find type `V` in this scope [E0412]
+{
+}
+
+fn main() {
+    bar();
+}

tests/ui/closures/issue-112547.stderr

@@ -0,0 +1,23 @@
+error[E0412]: cannot find type `V` in this scope
+  --> $DIR/issue-112547.rs:8:4
+   |
+LL | }> V: IntoIterator
+   |    ^ not found in this scope
+   |
+help: you might be missing a type parameter
+   |
+LL | pub fn bar<V>()
+   |           +++
+
+warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/issue-112547.rs:1:12
+   |
+LL | #![feature(non_lifetime_binders)]
+   |            ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0412`.