X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fcollapsible_if.rs;h=ae613d70240c39f7d94ca396fe5f15768f539524;hb=4d60841205d10293d6759df1948acda4c607c7eb;hp=fa0d7de6676eca5a28f62a4ec8acb44c6e0fba28;hpb=4018b0a495ee5d741958171dc98b2bb841a4b3aa;p=rust.git

diff --git a/clippy_lints/src/collapsible_if.rs b/clippy_lints/src/collapsible_if.rs
index fa0d7de6676..ae613d70240 100644
--- a/clippy_lints/src/collapsible_if.rs
+++ b/clippy_lints/src/collapsible_if.rs
@@ -1,3 +1,12 @@
+// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
 //! Checks for if expressions that contain only an if expression.
 //!
 //! For example, the lint would catch:
@@ -12,11 +21,14 @@
 //!
 //! This lint is **warn** by default
 
-use rustc::lint::*;
+use if_chain::if_chain;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
 use syntax::ast;
 
-use utils::{in_macro, snippet_block, span_lint_and_sugg, span_lint_and_then};
-use utils::sugg::Sugg;
+use crate::utils::sugg::Sugg;
+use crate::utils::{in_macro, snippet_block, snippet_block_with_applicability, span_lint_and_sugg, span_lint_and_then};
+use rustc_errors::Applicability;
 
 /// **What it does:** Checks for nested `if` statements which can be collapsed
 /// by `&&`-combining their conditions and for `else { if ... }` expressions
@@ -62,9 +74,9 @@
 ///     …
 /// }
 /// ```
-declare_lint! {
+declare_clippy_lint! {
     pub COLLAPSIBLE_IF,
-    Warn,
+    style,
     "`if`s that can be collapsed (e.g. `if x { if y { ... } }` and `else { if x { ... } }`)"
 }
 
@@ -78,19 +90,21 @@ fn get_lints(&self) -> LintArray {
 }
 
 impl EarlyLintPass for CollapsibleIf {
-    fn check_expr(&mut self, cx: &EarlyContext, expr: &ast::Expr) {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
         if !in_macro(expr.span) {
             check_if(cx, expr)
         }
     }
 }
 
-fn check_if(cx: &EarlyContext, expr: &ast::Expr) {
+fn check_if(cx: &EarlyContext<'_>, expr: &ast::Expr) {
     match expr.node {
-        ast::ExprKind::If(ref check, ref then, ref else_) => if let Some(ref else_) = *else_ {
-            check_collapsible_maybe_if_let(cx, else_);
-        } else {
-            check_collapsible_no_if_let(cx, expr, check, then);
+        ast::ExprKind::If(ref check, ref then, ref else_) => {
+            if let Some(ref else_) = *else_ {
+                check_collapsible_maybe_if_let(cx, else_);
+            } else {
+                check_collapsible_no_if_let(cx, expr, check, then);
+            }
         },
         ast::ExprKind::IfLet(_, _, _, Some(ref else_)) => {
             check_collapsible_maybe_if_let(cx, else_);
@@ -99,20 +113,33 @@ fn check_if(cx: &EarlyContext, expr: &ast::Expr) {
     }
 }
 
-fn check_collapsible_maybe_if_let(cx: &EarlyContext, else_: &ast::Expr) {
+fn block_starts_with_comment(cx: &EarlyContext<'_>, expr: &ast::Block) -> bool {
+    // We trim all opening braces and whitespaces and then check if the next string is a comment.
+    let trimmed_block_text = snippet_block(cx, expr.span, "..")
+        .trim_start_matches(|c: char| c.is_whitespace() || c == '{')
+        .to_owned();
+    trimmed_block_text.starts_with("//") || trimmed_block_text.starts_with("/*")
+}
+
+fn check_collapsible_maybe_if_let(cx: &EarlyContext<'_>, else_: &ast::Expr) {
     if_chain! {
-        if let ast::ExprKind::Block(ref block) = else_.node;
+        if let ast::ExprKind::Block(ref block, _) = else_.node;
+        if !block_starts_with_comment(cx, block);
         if let Some(else_) = expr_block(block);
         if !in_macro(else_.span);
         then {
             match else_.node {
                 ast::ExprKind::If(..) | ast::ExprKind::IfLet(..) => {
-                    span_lint_and_sugg(cx,
-                                       COLLAPSIBLE_IF,
-                                       block.span,
-                                       "this `else { if .. }` block can be collapsed",
-                                       "try",
-                                       snippet_block(cx, else_.span, "..").into_owned());
+                    let mut applicability = Applicability::MachineApplicable;
+                    span_lint_and_sugg(
+                        cx,
+                        COLLAPSIBLE_IF,
+                        block.span,
+                        "this `else { if .. }` block can be collapsed",
+                        "try",
+                        snippet_block_with_applicability(cx, else_.span, "..", &mut applicability).into_owned(),
+                        applicability,
+                    );
                 }
                 _ => (),
             }
@@ -120,8 +147,9 @@ fn check_collapsible_maybe_if_let(cx: &EarlyContext, else_: &ast::Expr) {
     }
 }
 
-fn check_collapsible_no_if_let(cx: &EarlyContext, expr: &ast::Expr, check: &ast::Expr, then: &ast::Block) {
+fn check_collapsible_no_if_let(cx: &EarlyContext<'_>, expr: &ast::Expr, check: &ast::Expr, then: &ast::Block) {
     if_chain! {
+        if !block_starts_with_comment(cx, then);
         if let Some(inner) = expr_block(then);
         if let ast::ExprKind::If(ref check_inner, ref content, None) = inner.node;
         then {
@@ -131,11 +159,16 @@ fn check_collapsible_no_if_let(cx: &EarlyContext, expr: &ast::Expr, check: &ast:
             span_lint_and_then(cx, COLLAPSIBLE_IF, expr.span, "this if statement can be collapsed", |db| {
                 let lhs = Sugg::ast(cx, check, "..");
                 let rhs = Sugg::ast(cx, check_inner, "..");
-                db.span_suggestion(expr.span,
-                                   "try",
-                                   format!("if {} {}",
-                                           lhs.and(&rhs),
-                                           snippet_block(cx, content.span, "..")));
+                db.span_suggestion_with_applicability(
+                    expr.span,
+                    "try",
+                    format!(
+                        "if {} {}",
+                        lhs.and(&rhs),
+                        snippet_block(cx, content.span, ".."),
+                    ),
+                    Applicability::MachineApplicable, // snippet
+                );
             });
         }
     }