modify code

[rust.git] / clippy_lints / src / returns.rs

diff --git a/clippy_lints/src/returns.rs b/clippy_lints/src/returns.rs
index 494bc7dda18e76008aebf3460fb1d64b4a88d0ee..8068fa22d9ccf8eea0fb4801d0d9b3f92193184a 100644 (file)
--- a/clippy_lints/src/returns.rs
+++ b/clippy_lints/src/returns.rs
@@ -4,10 +4,9 @@
 use if_chain::if_chain;
 use rustc_ast::ast::Attribute;
 use rustc_errors::Applicability;
-use rustc_hir::intravisit::{walk_expr, FnKind, NestedVisitorMap, Visitor};
+use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
 use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, HirId, MatchSource, PatKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::hir::map::Map;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -73,6 +72,7 @@
 enum RetReplacement {
     Empty,
     Block,
+    Unit,
 }
 
 declare_lint_pass!(Return => [LET_AND_RETURN, NEEDLESS_RETURN]);
@@ -212,7 +212,7 @@ fn check_final_expr<'tcx>(
         // (except for unit type functions) so we don't match it
         ExprKind::Match(_, arms, MatchSource::Normal) => {
             for arm in arms.iter() {
-                check_final_expr(cx, arm.body, Some(arm.body.span), RetReplacement::Block);
+                check_final_expr(cx, arm.body, Some(arm.body.span), RetReplacement::Unit);
             }
         },
         ExprKind::DropTemps(expr) => check_final_expr(cx, expr, None, RetReplacement::Empty),
@@ -259,6 +259,17 @@ fn emit_return_lint(cx: &LateContext<'_>, ret_span: Span, inner_span: Option<Spa
                     Applicability::MachineApplicable,
                 );
             },
+            RetReplacement::Unit => {
+                span_lint_and_sugg(
+                    cx,
+                    NEEDLESS_RETURN,
+                    ret_span,
+                    "unneeded `return` statement",
+                    "replace `return` with a unit value",
+                    "()".to_string(),
+                    Applicability::MachineApplicable,
+                );
+            },
         },
     }
 }
@@ -275,8 +286,6 @@ struct BorrowVisitor<'a, 'tcx> {
 }
 
 impl<'tcx> Visitor<'tcx> for BorrowVisitor<'_, 'tcx> {
-    type Map = Map<'tcx>;
-
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
         if self.borrows {
             return;
@@ -289,14 +298,10 @@ fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
                 .fn_sig(def_id)
                 .output()
                 .skip_binder()
-                .walk(self.cx.tcx)
+                .walk()
                 .any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
         }
 
         walk_expr(self, expr);
     }
-
-    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
-        NestedVisitorMap::None
-    }
 }