Use `utils::sugg` in `COLLAPSIBLE_IF`

clippy_lints/src/collapsible_if.rs

@@ -13,11 +13,10 @@
 //! This lint is **warn** by default
 
 use rustc::lint::*;
-use std::borrow::Cow;
-use syntax::codemap::Spanned;
 use syntax::ast;
 
-use utils::{in_macro, snippet, snippet_block, span_lint_and_then};
+use utils::{in_macro, snippet_block, span_lint_and_then};
+use utils::sugg::Sugg;
 
 /// **What it does:** This lint checks for nested `if`-statements which can be collapsed by
 /// `&&`-combining their conditions and for `else { if .. }` expressions that can be collapsed to
@@ -103,31 +102,17 @@ fn check_collapsible_no_if_let(
             return;
         }
         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 {} && {} {}",
-                                       check_to_string(cx, check),
-                                       check_to_string(cx, check_inner),
+                               format!("if {} {}",
+                                       lhs.and(&rhs),
                                        snippet_block(cx, content.span, "..")));
         });
     }}
 }
 
-fn requires_brackets(e: &ast::Expr) -> bool {
-    match e.node {
-        ast::ExprKind::Binary(Spanned { node: n, .. }, _, _) if n == ast::BinOpKind::Eq => false,
-        _ => true,
-    }
-}
-
-fn check_to_string(cx: &EarlyContext, e: &ast::Expr) -> Cow<'static, str> {
-    if requires_brackets(e) {
-        format!("({})", snippet(cx, e.span, "..")).into()
-    } else {
-        snippet(cx, e.span, "..")
-    }
-}
-
 fn single_stmt_of_block(block: &ast::Block) -> Option<&ast::Expr> {
     if block.stmts.len() == 1 && block.expr.is_none() {
         if let ast::StmtKind::Expr(ref expr, _) = block.stmts[0].node {

tests/compile-fail/collapsible_if.rs

@@ -23,6 +23,42 @@ fn main() {
         }
     }
 
+    if x == "hello" && x == "world" {
+    //~^ ERROR this if statement can be collapsed
+    //~| HELP try
+    //~| SUGGESTION if x == "hello" && x == "world" && (y == "world" || y == "hello") {
+        if y == "world" || y == "hello" {
+            println!("Hello world!");
+        }
+    }
+
+    if x == "hello" || x == "world" {
+    //~^ ERROR this if statement can be collapsed
+    //~| HELP try
+    //~| SUGGESTION if (x == "hello" || x == "world") && y == "world" && y == "hello" {
+        if y == "world" && y == "hello" {
+            println!("Hello world!");
+        }
+    }
+
+    if x == "hello" && x == "world" {
+    //~^ ERROR this if statement can be collapsed
+    //~| HELP try
+    //~| SUGGESTION if x == "hello" && x == "world" && y == "world" && y == "hello" {
+        if y == "world" && y == "hello" {
+            println!("Hello world!");
+        }
+    }
+
+    if 42 == 1337 {
+    //~^ ERROR this if statement can be collapsed
+    //~| HELP try
+    //~| SUGGESTION if 42 == 1337 && 'a' != 'A' {
+        if 'a' != 'A' {
+            println!("world!")
+        }
+    }
+
     // Collaspe `else { if .. }` to `else if ..`
     if x == "hello" {
         print!("Hello ");