Visit generic parameters in where predicate in order to prevent ICE due to not bound vars.

Author: lenko-d

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -897,6 +897,24 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                         })
                         .unzip();
                 self.record_late_bound_vars(hir_id, binders.clone());
+
+                for param in bound_generic_params {
+                    match param.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));
+                            }
+                        }
+                    }
+                }
+
                 // Even if there are no lifetimes defined here, we still wrap it in a binder
                 // scope. If there happens to be a nested poly trait ref (an error), that
                 // will be `Concatenating` anyways, so we don't have to worry about the depth

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`.