X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fno_effect.rs;h=e07518b25868795c691291bc01e28b8d9315e59b;hb=12c61612f7a91df64121dd9c991828c26d665325;hp=b8bfa676a16088cd6b412626308b033b833ddb74;hpb=24f6d643fe45c5acb489d3618736ac40559a883e;p=rust.git

diff --git a/clippy_lints/src/no_effect.rs b/clippy_lints/src/no_effect.rs
index b8bfa676a16..e07518b2586 100644
--- a/clippy_lints/src/no_effect.rs
+++ b/clippy_lints/src/no_effect.rs
@@ -1,4 +1,6 @@
-use crate::utils::{has_drop, qpath_res, snippet_opt, span_lint, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint_hir, span_lint_hir_and_then};
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::has_drop;
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
@@ -7,15 +9,15 @@
 use std::ops::Deref;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for statements which have no effect.
+    /// ### What it does
+    /// Checks for statements which have no effect.
     ///
-    /// **Why is this bad?** Similar to dead code, these statements are actually
+    /// ### Why is this bad?
+    /// Similar to dead code, these statements are actually
     /// executed. However, as they have no effect, all they do is make the code less
     /// readable.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// 0;
     /// ```
@@ -25,15 +27,15 @@
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for expression statements that can be reduced to a
+    /// ### What it does
+    /// Checks for expression statements that can be reduced to a
     /// sub-expression.
     ///
-    /// **Why is this bad?** Expressions by themselves often have no side-effects.
+    /// ### Why is this bad?
+    /// Expressions by themselves often have no side-effects.
     /// Having such expressions reduces readability.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// compute_array()[0];
     /// ```
@@ -42,35 +44,34 @@
     "outer expressions with no effect"
 }
 
-fn has_no_effect(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
+fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if expr.span.from_expansion() {
         return false;
     }
     match expr.kind {
         ExprKind::Lit(..) | ExprKind::Closure(..) => true,
-        ExprKind::Path(..) => !has_drop(cx, cx.tables.expr_ty(expr)),
-        ExprKind::Index(ref a, ref b) | ExprKind::Binary(_, ref a, ref b) => {
-            has_no_effect(cx, a) && has_no_effect(cx, b)
-        },
-        ExprKind::Array(ref v) | ExprKind::Tup(ref v) => v.iter().all(|val| has_no_effect(cx, val)),
-        ExprKind::Repeat(ref inner, _)
-        | ExprKind::Cast(ref inner, _)
-        | ExprKind::Type(ref inner, _)
-        | ExprKind::Unary(_, ref inner)
-        | ExprKind::Field(ref inner, _)
-        | ExprKind::AddrOf(_, _, ref inner)
-        | ExprKind::Box(ref inner) => has_no_effect(cx, inner),
-        ExprKind::Struct(_, ref fields, ref base) => {
-            !has_drop(cx, cx.tables.expr_ty(expr))
-                && fields.iter().all(|field| has_no_effect(cx, &field.expr))
+        ExprKind::Path(..) => !has_drop(cx, cx.typeck_results().expr_ty(expr)),
+        ExprKind::Index(a, b) | ExprKind::Binary(_, a, b) => has_no_effect(cx, a) && has_no_effect(cx, b),
+        ExprKind::Array(v) | ExprKind::Tup(v) => v.iter().all(|val| has_no_effect(cx, val)),
+        ExprKind::Repeat(inner, _)
+        | ExprKind::Cast(inner, _)
+        | ExprKind::Type(inner, _)
+        | ExprKind::Unary(_, inner)
+        | ExprKind::Field(inner, _)
+        | ExprKind::AddrOf(_, _, inner)
+        | ExprKind::Box(inner) => has_no_effect(cx, inner),
+        ExprKind::Struct(_, fields, ref base) => {
+            !has_drop(cx, cx.typeck_results().expr_ty(expr))
+                && fields.iter().all(|field| has_no_effect(cx, field.expr))
                 && base.as_ref().map_or(true, |base| has_no_effect(cx, base))
         },
-        ExprKind::Call(ref callee, ref args) => {
+        ExprKind::Call(callee, args) => {
             if let ExprKind::Path(ref qpath) = callee.kind {
-                let res = qpath_res(cx, qpath, callee.hir_id);
+                let res = cx.qpath_res(qpath, callee.hir_id);
                 match res {
                     Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..) => {
-                        !has_drop(cx, cx.tables.expr_ty(expr)) && args.iter().all(|arg| has_no_effect(cx, arg))
+                        !has_drop(cx, cx.typeck_results().expr_ty(expr))
+                            && args.iter().all(|arg| has_no_effect(cx, arg))
                     },
                     _ => false,
                 }
@@ -78,7 +79,7 @@ fn has_no_effect(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
                 false
             }
         },
-        ExprKind::Block(ref block, _) => {
+        ExprKind::Block(block, _) => {
             block.stmts.is_empty() && block.expr.as_ref().map_or(false, |expr| has_no_effect(cx, expr))
         },
         _ => false,
@@ -87,11 +88,11 @@ fn has_no_effect(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
 
 declare_lint_pass!(NoEffect => [NO_EFFECT, UNNECESSARY_OPERATION]);
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NoEffect {
-    fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt<'_>) {
-        if let StmtKind::Semi(ref expr) = stmt.kind {
+impl<'tcx> LateLintPass<'tcx> for NoEffect {
+    fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
+        if let StmtKind::Semi(expr) = stmt.kind {
             if has_no_effect(cx, expr) {
-                span_lint(cx, NO_EFFECT, stmt.span, "statement with no effect");
+                span_lint_hir(cx, NO_EFFECT, expr.hir_id, stmt.span, "statement with no effect");
             } else if let Some(reduced) = reduce_expression(cx, expr) {
                 let mut snippet = String::new();
                 for e in reduced {
@@ -105,50 +106,51 @@ fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt<'_>) {
                         return;
                     }
                 }
-                span_lint_and_sugg(
+                span_lint_hir_and_then(
                     cx,
                     UNNECESSARY_OPERATION,
+                    expr.hir_id,
                     stmt.span,
                     "statement can be reduced",
-                    "replace it with",
-                    snippet,
-                    Applicability::MachineApplicable,
+                    |diag| {
+                        diag.span_suggestion(stmt.span, "replace it with", snippet, Applicability::MachineApplicable);
+                    },
                 );
             }
         }
     }
 }
 
-fn reduce_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a Expr<'a>) -> Option<Vec<&'a Expr<'a>>> {
+fn reduce_expression<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<Vec<&'a Expr<'a>>> {
     if expr.span.from_expansion() {
         return None;
     }
     match expr.kind {
-        ExprKind::Index(ref a, ref b) => Some(vec![&**a, &**b]),
-        ExprKind::Binary(ref binop, ref a, ref b) if binop.node != BinOpKind::And && binop.node != BinOpKind::Or => {
-            Some(vec![&**a, &**b])
+        ExprKind::Index(a, b) => Some(vec![a, b]),
+        ExprKind::Binary(ref binop, a, b) if binop.node != BinOpKind::And && binop.node != BinOpKind::Or => {
+            Some(vec![a, b])
         },
-        ExprKind::Array(ref v) | ExprKind::Tup(ref v) => Some(v.iter().collect()),
-        ExprKind::Repeat(ref inner, _)
-        | ExprKind::Cast(ref inner, _)
-        | ExprKind::Type(ref inner, _)
-        | ExprKind::Unary(_, ref inner)
-        | ExprKind::Field(ref inner, _)
-        | ExprKind::AddrOf(_, _, ref inner)
-        | ExprKind::Box(ref inner) => reduce_expression(cx, inner).or_else(|| Some(vec![inner])),
-        ExprKind::Struct(_, ref fields, ref base) => {
-            if has_drop(cx, cx.tables.expr_ty(expr)) {
+        ExprKind::Array(v) | ExprKind::Tup(v) => Some(v.iter().collect()),
+        ExprKind::Repeat(inner, _)
+        | ExprKind::Cast(inner, _)
+        | ExprKind::Type(inner, _)
+        | ExprKind::Unary(_, inner)
+        | ExprKind::Field(inner, _)
+        | ExprKind::AddrOf(_, _, inner)
+        | ExprKind::Box(inner) => reduce_expression(cx, inner).or_else(|| Some(vec![inner])),
+        ExprKind::Struct(_, fields, ref base) => {
+            if has_drop(cx, cx.typeck_results().expr_ty(expr)) {
                 None
             } else {
                 Some(fields.iter().map(|f| &f.expr).chain(base).map(Deref::deref).collect())
             }
         },
-        ExprKind::Call(ref callee, ref args) => {
+        ExprKind::Call(callee, args) => {
             if let ExprKind::Path(ref qpath) = callee.kind {
-                let res = qpath_res(cx, qpath, callee.hir_id);
+                let res = cx.qpath_res(qpath, callee.hir_id);
                 match res {
-                    Res::Def(DefKind::Struct, ..) | Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
-                        if !has_drop(cx, cx.tables.expr_ty(expr)) =>
+                    Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..)
+                        if !has_drop(cx, cx.typeck_results().expr_ty(expr)) =>
                     {
                         Some(args.iter().collect())
                     },
@@ -158,14 +160,14 @@ fn reduce_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a Expr<'a>) -> Option
                 None
             }
         },
-        ExprKind::Block(ref block, _) => {
+        ExprKind::Block(block, _) => {
             if block.stmts.is_empty() {
                 block.expr.as_ref().and_then(|e| {
                     match block.rules {
                         BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided) => None,
                         BlockCheckMode::DefaultBlock => Some(vec![&**e]),
                         // in case of compiler-inserted signaling blocks
-                        _ => reduce_expression(cx, e),
+                        BlockCheckMode::UnsafeBlock(_) => reduce_expression(cx, e),
                     }
                 })
             } else {