Hide outermost_fn_param_pat, it's an internal detail

compiler/rustc_typeck/src/check/check.rs

@@ -105,7 +105,7 @@ pub(super) fn check_fn<'a, 'tcx>(
 
     let outer_def_id = tcx.closure_base_def_id(hir.local_def_id(fn_id).to_def_id()).expect_local();
     let outer_hir_id = hir.local_def_id_to_hir_id(outer_def_id);
-    GatherLocalsVisitor::new(&fcx, outer_hir_id, false).visit_body(body);
+    GatherLocalsVisitor::new(&fcx, outer_hir_id).visit_body(body);
 
     // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
     // (as it's created inside the body itself, not passed in from outside).

compiler/rustc_typeck/src/check/gather_locals.rs

@@ -18,12 +18,8 @@ pub(super) struct GatherLocalsVisitor<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> GatherLocalsVisitor<'a, 'tcx> {
-    pub(super) fn new(
-        fcx: &'a FnCtxt<'a, 'tcx>,
-        parent_id: hir::HirId,
-        outermost_fn_param_pat: bool,
-    ) -> Self {
-        Self { fcx, parent_id, outermost_fn_param_pat }
+    pub(super) fn new(fcx: &'a FnCtxt<'a, 'tcx>, parent_id: hir::HirId) -> Self {
+        Self { fcx, parent_id, outermost_fn_param_pat: false }
     }
 
     fn assign(&mut self, span: Span, nid: hir::HirId, ty_opt: Option<LocalTy<'tcx>>) -> Ty<'tcx> {

compiler/rustc_typeck/src/check/mod.rs

@@ -553,7 +553,7 @@ fn typeck_with_fallback<'tcx>(
             };
 
             // Gather locals in statics (because of block expressions).
-            GatherLocalsVisitor::new(&fcx, id, false).visit_body(body);
+            GatherLocalsVisitor::new(&fcx, id).visit_body(body);
 
             fcx.check_expr_coercable_to_type(&body.value, revealed_ty, None);