feat: remove callback param for walk_local method

Author: Embers-of-the-Fire

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -451,7 +451,7 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
             }
 
             hir::ExprKind::Let(hir::LetExpr { pat, init, .. }) => {
-                self.walk_local(init, pat, None, || Ok(()))?;
+                self.walk_local(init, pat, None)?;
             }
 
             hir::ExprKind::Match(discr, arms, _) => {
@@ -577,7 +577,7 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
     fn walk_stmt(&self, stmt: &hir::Stmt<'_>) -> Result<(), Cx::Error> {
         match stmt.kind {
             hir::StmtKind::Let(hir::LetStmt { pat, init: Some(expr), els, .. }) => {
-                self.walk_local(expr, pat, *els, || Ok(()))?;
+                self.walk_local(expr, pat, *els)?;
             }
 
             hir::StmtKind::Let(_) => {}
@@ -617,19 +617,14 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
         Ok(())
     }
 
-    fn walk_local<F>(
+    fn walk_local(
         &self,
         expr: &hir::Expr<'_>,
         pat: &hir::Pat<'_>,
         els: Option<&hir::Block<'_>>,
-        mut f: F,
-    ) -> Result<(), Cx::Error>
-    where
-        F: FnMut() -> Result<(), Cx::Error>,
-    {
+    ) -> Result<(), Cx::Error> {
         self.walk_expr(expr)?;
         let expr_place = self.cat_expr(expr)?;
-        f()?;
         self.fake_read_scrutinee(&expr_place, els.is_some())?;
         self.walk_pat(&expr_place, pat, false)?;
         if let Some(els) = els {