range_plus_one suggestion should not remove braces fix

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

diff --git a/clippy_lints/src/ranges.rs b/clippy_lints/src/ranges.rs
index 6ec624d26e9271a10b4e239274565d971f3d6003..d86f264addab99df26b4fc4dac7f558fabff08bf 100644 (file)
--- a/clippy_lints/src/ranges.rs
+++ b/clippy_lints/src/ranges.rs
@@ -1,9 +1,11 @@
-use rustc::lint::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
 use rustc::hir::*;
 use syntax::ast::RangeLimits;
-use syntax::codemap::Spanned;
-use crate::utils::{is_integer_literal, paths, snippet, span_lint, span_lint_and_then};
-use crate::utils::{get_trait_def_id, higher, implements_trait};
+use syntax::source_map::Spanned;
+use crate::utils::{is_integer_literal, paths, snippet, span_lint, span_lint_and_then, snippet_opt};
+use crate::utils::{get_trait_def_id, higher, implements_trait, SpanlessEq};
 use crate::utils::sugg::Sugg;
 
 /// **What it does:** Checks for calling `.step_by(0)` on iterators,
@@ -47,7 +49,10 @@
 /// **Why is this bad?** The code is more readable with an inclusive range
 /// like `x..=y`.
 ///
-/// **Known problems:** None.
+/// **Known problems:** Will add unnecessary pair of parentheses when the
+/// expression is not wrapped in a pair but starts with a opening parenthesis
+/// and ends with a closing one.
+/// I.e: let _ = (f()+1)..(f()+1) results in let _ = ((f()+1)..(f()+1)).
 ///
 /// **Example:**
 /// ```rust
@@ -55,7 +60,7 @@
 /// ```
 declare_clippy_lint! {
     pub RANGE_PLUS_ONE,
-    nursery,
+    complexity,
     "`x..(y+1)` reads better as `x..=y`"
 }
 
@@ -73,7 +78,7 @@
 /// ```
 declare_clippy_lint! {
     pub RANGE_MINUS_ONE,
-    style,
+    complexity,
     "`x..=(y-1)` reads better as `x..y`"
 }
 
@@ -88,7 +93,7 @@ fn get_lints(&self) -> LintArray {
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
-        if let ExprMethodCall(ref path, _, ref args) = expr.node {
+        if let ExprKind::MethodCall(ref path, _, ref args) = expr.node {
             let name = path.ident.as_str();
 
             // Range with step_by(0).
@@ -107,18 +112,18 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
                 let zip_arg = &args[1];
                 if_chain! {
                     // .iter() call
-                    if let ExprMethodCall(ref iter_path, _, ref iter_args ) = *iter;
+                    if let ExprKind::MethodCall(ref iter_path, _, ref iter_args ) = *iter;
                     if iter_path.ident.name == "iter";
                     // range expression in .zip() call: 0..x.len()
                     if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::range(cx, zip_arg);
                     if is_integer_literal(start, 0);
                     // .len() call
-                    if let ExprMethodCall(ref len_path, _, ref len_args) = end.node;
+                    if let ExprKind::MethodCall(ref len_path, _, ref len_args) = end.node;
                     if len_path.ident.name == "len" && len_args.len() == 1;
                     // .iter() and .len() called on same Path
-                    if let ExprPath(QPath::Resolved(_, ref iter_path)) = iter_args[0].node;
-                    if let ExprPath(QPath::Resolved(_, ref len_path)) = len_args[0].node;
-                    if iter_path.segments == len_path.segments;
+                    if let ExprKind::Path(QPath::Resolved(_, ref iter_path)) = iter_args[0].node;
+                    if let ExprKind::Path(QPath::Resolved(_, ref len_path)) = len_args[0].node;
+                    if SpanlessEq::new(cx).eq_path_segments(&iter_path.segments, &len_path.segments);
                      then {
                          span_lint(cx,
                                    RANGE_ZIP_WITH_LEN,
@@ -143,9 +148,17 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
                     |db| {
                         let start = start.map_or("".to_owned(), |x| Sugg::hir(cx, x, "x").to_string());
                         let end = Sugg::hir(cx, y, "y");
-                        db.span_suggestion(expr.span,
+                        if let Some(is_wrapped) = &snippet_opt(cx, expr.span) {
+                            if is_wrapped.starts_with("(") && is_wrapped.ends_with(")") {
+                                db.span_suggestion(expr.span,
+                                           "use",
+                                           format!("({}..={})", start, end));
+                            } else {
+                                db.span_suggestion(expr.span,
                                            "use",
                                            format!("{}..={}", start, end));
+                            }
+                        }
                     },
                 );
             }
@@ -174,7 +187,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
     }
 }
 
-fn has_step_by(cx: &LateContext, expr: &Expr) -> bool {
+fn has_step_by(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
     // No need for walk_ptrs_ty here because step_by moves self, so it
     // can't be called on a borrowed range.
     let ty = cx.tables.expr_ty_adjusted(expr);
@@ -184,7 +197,7 @@ fn has_step_by(cx: &LateContext, expr: &Expr) -> bool {
 
 fn y_plus_one(expr: &Expr) -> Option<&Expr> {
     match expr.node {
-        ExprBinary(Spanned { node: BiAdd, .. }, ref lhs, ref rhs) => if is_integer_literal(lhs, 1) {
+        ExprKind::Binary(Spanned { node: BinOpKind::Add, .. }, ref lhs, ref rhs) => if is_integer_literal(lhs, 1) {
             Some(rhs)
         } else if is_integer_literal(rhs, 1) {
             Some(lhs)
@@ -197,7 +210,7 @@ fn y_plus_one(expr: &Expr) -> Option<&Expr> {
 
 fn y_minus_one(expr: &Expr) -> Option<&Expr> {
     match expr.node {
-        ExprBinary(Spanned { node: BiSub, .. }, ref lhs, ref rhs) if is_integer_literal(rhs, 1) => Some(lhs),
+        ExprKind::Binary(Spanned { node: BinOpKind::Sub, .. }, ref lhs, ref rhs) if is_integer_literal(rhs, 1) => Some(lhs),
         _ => None,
     }
 }