Auto merge of #3946 - rchaser53:issue-3920, r=flip1995

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

diff --git a/clippy_lints/src/identity_conversion.rs b/clippy_lints/src/identity_conversion.rs
index d8b8e8f073b2cbdfacc334f614cf1233de8e8a88..7391f0a5208eba617164a51bac329353315d7a25 100644 (file)
--- a/clippy_lints/src/identity_conversion.rs
+++ b/clippy_lints/src/identity_conversion.rs
@@ -1,35 +1,42 @@
-use rustc::lint::*;
+use crate::utils::{
+    in_macro, match_def_path, match_trait_method, same_tys, snippet, snippet_with_macro_callsite, span_lint_and_then,
+};
+use crate::utils::{paths, resolve_node};
 use rustc::hir::*;
-use syntax::ast::NodeId;
-use crate::utils::{in_macro, match_def_path, match_trait_method, same_tys, snippet, span_lint_and_then};
-use crate::utils::{opt_def_id, paths, resolve_node};
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
+use rustc_errors::Applicability;
 
-/// **What it does:** Checks for always-identical `Into`/`From` conversions.
-///
-/// **Why is this bad?** Redundant code.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// // format!() returns a `String`
-/// let s: String = format!("hello").into();
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for always-identical `Into`/`From`/`IntoIter` conversions.
+    ///
+    /// **Why is this bad?** Redundant code.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// // format!() returns a `String`
+    /// let s: String = format!("hello").into();
+    /// ```
     pub IDENTITY_CONVERSION,
     complexity,
-    "using always-identical `Into`/`From` conversions"
+    "using always-identical `Into`/`From`/`IntoIter` conversions"
 }
 
 #[derive(Default)]
 pub struct IdentityConversion {
-    try_desugar_arm: Vec<NodeId>,
+    try_desugar_arm: Vec<HirId>,
 }
 
 impl LintPass for IdentityConversion {
     fn get_lints(&self) -> LintArray {
         lint_array!(IDENTITY_CONVERSION)
     }
+
+    fn name(&self) -> &'static str {
+        "IdentityConversion"
+    }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for IdentityConversion {
@@ -38,47 +45,76 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
             return;
         }
 
-        if Some(&e.id) == self.try_desugar_arm.last() {
+        if Some(&e.hir_id) == self.try_desugar_arm.last() {
             return;
         }
 
         match e.node {
-            ExprMatch(_, ref arms, MatchSource::TryDesugar) => {
+            ExprKind::Match(_, ref arms, MatchSource::TryDesugar) => {
                 let e = match arms[0].body.node {
-                    ExprRet(Some(ref e)) | ExprBreak(_, Some(ref e)) => e,
+                    ExprKind::Ret(Some(ref e)) | ExprKind::Break(_, Some(ref e)) => e,
                     _ => return,
                 };
-                if let ExprCall(_, ref args) = e.node {
-                    self.try_desugar_arm.push(args[0].id);
+                if let ExprKind::Call(_, ref args) = e.node {
+                    self.try_desugar_arm.push(args[0].hir_id);
                 } else {
                     return;
                 }
             },
 
-            ExprMethodCall(ref name, .., ref args) => {
-                if match_trait_method(cx, e, &paths::INTO[..]) && &*name.name.as_str() == "into" {
+            ExprKind::MethodCall(ref name, .., ref args) => {
+                if match_trait_method(cx, e, &paths::INTO[..]) && &*name.ident.as_str() == "into" {
+                    let a = cx.tables.expr_ty(e);
+                    let b = cx.tables.expr_ty(&args[0]);
+                    if same_tys(cx, a, b) {
+                        let sugg = snippet_with_macro_callsite(cx, args[0].span, "<expr>").to_string();
+
+                        span_lint_and_then(cx, IDENTITY_CONVERSION, e.span, "identical conversion", |db| {
+                            db.span_suggestion(
+                                e.span,
+                                "consider removing `.into()`",
+                                sugg,
+                                Applicability::MachineApplicable, // snippet
+                            );
+                        });
+                    }
+                }
+                if match_trait_method(cx, e, &paths::INTO_ITERATOR) && &*name.ident.as_str() == "into_iter" {
                     let a = cx.tables.expr_ty(e);
                     let b = cx.tables.expr_ty(&args[0]);
                     if same_tys(cx, a, b) {
                         let sugg = snippet(cx, args[0].span, "<expr>").into_owned();
                         span_lint_and_then(cx, IDENTITY_CONVERSION, e.span, "identical conversion", |db| {
-                            db.span_suggestion(e.span, "consider removing `.into()`", sugg);
+                            db.span_suggestion(
+                                e.span,
+                                "consider removing `.into_iter()`",
+                                sugg,
+                                Applicability::MachineApplicable, // snippet
+                            );
                         });
                     }
                 }
             },
 
-            ExprCall(ref path, ref args) => if let ExprPath(ref qpath) = path.node {
-                if let Some(def_id) = opt_def_id(resolve_node(cx, qpath, path.hir_id)) {
-                    if match_def_path(cx.tcx, def_id, &paths::FROM_FROM[..]) {
-                        let a = cx.tables.expr_ty(e);
-                        let b = cx.tables.expr_ty(&args[0]);
-                        if same_tys(cx, a, b) {
-                            let sugg = snippet(cx, args[0].span, "<expr>").into_owned();
-                            let sugg_msg = format!("consider removing `{}()`", snippet(cx, path.span, "From::from"));
-                            span_lint_and_then(cx, IDENTITY_CONVERSION, e.span, "identical conversion", |db| {
-                                db.span_suggestion(e.span, &sugg_msg, sugg);
-                            });
+            ExprKind::Call(ref path, ref args) => {
+                if let ExprKind::Path(ref qpath) = path.node {
+                    if let Some(def_id) = resolve_node(cx, qpath, path.hir_id).opt_def_id() {
+                        if match_def_path(cx.tcx, def_id, &paths::FROM_FROM[..]) {
+                            let a = cx.tables.expr_ty(e);
+                            let b = cx.tables.expr_ty(&args[0]);
+                            if same_tys(cx, a, b) {
+                                let sugg = snippet(cx, args[0].span.source_callsite(), "<expr>").into_owned();
+                                let sugg_msg =
+                                    format!("consider removing `{}()`", snippet(cx, path.span, "From::from"));
+                                span_lint_and_then(cx, IDENTITY_CONVERSION, e.span, "identical conversion", |db| {
+                                    db.span_suggestion(
+                                        e.span,
+                                        &sugg_msg,
+                                        sugg,
+                                        Applicability::MachineApplicable, // snippet
+                                    );
+                                });
+                            }
                         }
                     }
                 }
@@ -89,7 +125,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
     }
 
     fn check_expr_post(&mut self, _: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
-        if Some(&e.id) == self.try_desugar_arm.last() {
+        if Some(&e.hir_id) == self.try_desugar_arm.last() {
             self.try_desugar_arm.pop();
         }
     }