Auto merge of #3596 - xfix:remove-crate-from-paths, r=flip1995

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

diff --git a/clippy_lints/src/collapsible_if.rs b/clippy_lints/src/collapsible_if.rs
index b0fb058116f2390b64d60464dc5aa7b17b746cb0..ae613d70240c39f7d94ca396fe5f15768f539524 100644 (file)
--- 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:
@@ -12,14 +21,14 @@
 //!
 //! This lint is **warn** by default
 
-use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
 use if_chain::if_chain;
-use crate::syntax::ast;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
+use syntax::ast;
 
-use crate::utils::{in_macro, snippet_block, span_lint_and_sugg, span_lint_and_then};
 use crate::utils::sugg::Sugg;
-use crate::rustc_errors::Applicability;
+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
@@ -90,10 +99,12 @@ fn check_expr(&mut self, 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_);
@@ -102,20 +113,33 @@ fn check_if(cx: &EarlyContext<'_>, expr: &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 !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,
+                    );
                 }
                 _ => (),
             }
@@ -125,6 +149,7 @@ 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) {
     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 {