Auto merge of #9148 - arieluy:then_some_unwrap_or, r=Jarcho

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

diff --git a/clippy_lints/src/unused_self.rs b/clippy_lints/src/unused_self.rs
index 73c64b808405819239ca856976b32c61469e57b8..51c65d898cf5ffe8dc44758ddda8633576b4bd39 100644 (file)
--- a/clippy_lints/src/unused_self.rs
+++ b/clippy_lints/src/unused_self.rs
@@ -1,22 +1,19 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::visitors::is_local_used;
 use if_chain::if_chain;
-use rustc_hir::def::Res;
-use rustc_hir::intravisit::{walk_path, NestedVisitorMap, Visitor};
-use rustc_hir::{HirId, Impl, ImplItem, ImplItemKind, ItemKind, Path};
+use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::hir::map::Map;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-
-use crate::utils::span_lint_and_help;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks methods that contain a `self` argument but don't use it
+    /// ### What it does
+    /// Checks methods that contain a `self` argument but don't use it
     ///
-    /// **Why is this bad?** It may be clearer to define the method as an associated function instead
+    /// ### Why is this bad?
+    /// It may be clearer to define the method as an associated function instead
     /// of an instance method if it doesn't require `self`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// struct A;
     /// impl A {
@@ -32,12 +29,25 @@
     ///     fn method() {}
     /// }
     /// ```
+    #[clippy::version = "1.40.0"]
     pub UNUSED_SELF,
     pedantic,
     "methods that contain a `self` argument but don't use it"
 }
 
-declare_lint_pass!(UnusedSelf => [UNUSED_SELF]);
+pub struct UnusedSelf {
+    avoid_breaking_exported_api: bool,
+}
+
+impl_lint_pass!(UnusedSelf => [UNUSED_SELF]);
+
+impl UnusedSelf {
+    pub fn new(avoid_breaking_exported_api: bool) -> Self {
+        Self {
+            avoid_breaking_exported_api,
+        }
+    }
+}
 
 impl<'tcx> LateLintPass<'tcx> for UnusedSelf {
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &ImplItem<'_>) {
@@ -51,54 +61,20 @@ fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &ImplItem<'_>)
             if let ItemKind::Impl(Impl { of_trait: None, .. }) = parent_item.kind;
             if assoc_item.fn_has_self_parameter;
             if let ImplItemKind::Fn(.., body_id) = &impl_item.kind;
+            if !cx.access_levels.is_exported(impl_item.def_id) || !self.avoid_breaking_exported_api;
             let body = cx.tcx.hir().body(*body_id);
-            if !body.params.is_empty();
+            if let [self_param, ..] = body.params;
+            if !is_local_used(cx, body, self_param.pat.hir_id);
             then {
-                let self_param = &body.params[0];
-                let self_hir_id = self_param.pat.hir_id;
-                let mut visitor = UnusedSelfVisitor {
+                span_lint_and_help(
                     cx,
-                    uses_self: false,
-                    self_hir_id: &self_hir_id,
-                };
-                visitor.visit_body(body);
-                if !visitor.uses_self {
-                    span_lint_and_help(
-                        cx,
-                        UNUSED_SELF,
-                        self_param.span,
-                        "unused `self` argument",
-                        None,
-                        "consider refactoring to a associated function",
-                    );
-                    return;
-                }
+                    UNUSED_SELF,
+                    self_param.span,
+                    "unused `self` argument",
+                    None,
+                    "consider refactoring to a associated function",
+                );
             }
         }
     }
 }
-
-struct UnusedSelfVisitor<'a, 'tcx> {
-    cx: &'a LateContext<'tcx>,
-    uses_self: bool,
-    self_hir_id: &'a HirId,
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for UnusedSelfVisitor<'a, 'tcx> {
-    type Map = Map<'tcx>;
-
-    fn visit_path(&mut self, path: &'tcx Path<'_>, _id: HirId) {
-        if self.uses_self {
-            // This function already uses `self`
-            return;
-        }
-        if let Res::Local(hir_id) = &path.res {
-            self.uses_self = self.self_hir_id == hir_id
-        }
-        walk_path(self, path);
-    }
-
-    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
-        NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
-    }
-}