Give more corrected code examples in doc

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

diff --git a/clippy_lints/src/strings.rs b/clippy_lints/src/strings.rs
index 00e2441becf8129f8b6e283fb7e23eea8e74daa2..f84566ef707a8e41dbc8a2b00275d7d55c07aeb6 100644 (file)
--- a/clippy_lints/src/strings.rs
+++ b/clippy_lints/src/strings.rs
@@ -1,13 +1,14 @@
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
 use rustc_errors::Applicability;
-use syntax::source_map::Spanned;
+use rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Spanned;
 
 use if_chain::if_chain;
 
 use crate::utils::SpanlessEq;
-use crate::utils::{get_parent_expr, is_allowed, match_type, paths, span_lint, span_lint_and_sugg, walk_ptrs_ty};
+use crate::utils::{get_parent_expr, is_allowed, is_type_diagnostic_item, span_lint, span_lint_and_sugg, walk_ptrs_ty};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for string appends of the form `x = x + y` (without
@@ -23,6 +24,10 @@
     /// ```rust
     /// let mut x = "Hello".to_owned();
     /// x = x + ", World";
+    ///
+    /// // More readable
+    /// x += ", World";
+    /// x.push_str(", World");
     /// ```
     pub STRING_ADD_ASSIGN,
     pedantic,
@@ -68,7 +73,11 @@
     ///
     /// **Example:**
     /// ```rust
+    /// // Bad
     /// let bs = "a byte string".as_bytes();
+    ///
+    /// // Good
+    /// let bs = b"a byte string";
     /// ```
     pub STRING_LIT_AS_BYTES,
     style,
@@ -78,7 +87,11 @@
 declare_lint_pass!(StringAdd => [STRING_ADD, STRING_ADD_ASSIGN]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for StringAdd {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
+        if in_external_macro(cx.sess(), e.span) {
+            return;
+        }
+
         if let ExprKind::Binary(
             Spanned {
                 node: BinOpKind::Add, ..
@@ -91,7 +104,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
                 if !is_allowed(cx, STRING_ADD_ASSIGN, e.hir_id) {
                     let parent = get_parent_expr(cx, e);
                     if let Some(p) = parent {
-                        if let ExprKind::Assign(ref target, _) = p.kind {
+                        if let ExprKind::Assign(ref target, _, _) = p.kind {
                             // avoid duplicate matches
                             if SpanlessEq::new(cx).eq_expr(target, left) {
                                 return;
@@ -106,7 +119,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
                     "you added something to a string. Consider using `String::push_str()` instead",
                 );
             }
-        } else if let ExprKind::Assign(ref target, ref src) = e.kind {
+        } else if let ExprKind::Assign(ref target, ref src, _) = e.kind {
             if is_string(cx, target) && is_add(cx, src, target) {
                 span_lint(
                     cx,
@@ -120,11 +133,11 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
     }
 }
 
-fn is_string(cx: &LateContext<'_, '_>, e: &Expr) -> bool {
-    match_type(cx, walk_ptrs_ty(cx.tables.expr_ty(e)), &paths::STRING)
+fn is_string(cx: &LateContext<'_, '_>, e: &Expr<'_>) -> bool {
+    is_type_diagnostic_item(cx, walk_ptrs_ty(cx.tables.expr_ty(e)), sym!(string_type))
 }
 
-fn is_add(cx: &LateContext<'_, '_>, src: &Expr, target: &Expr) -> bool {
+fn is_add(cx: &LateContext<'_, '_>, src: &Expr<'_>, target: &Expr<'_>) -> bool {
     match src.kind {
         ExprKind::Binary(
             Spanned {
@@ -146,9 +159,9 @@ fn is_add(cx: &LateContext<'_, '_>, src: &Expr, target: &Expr) -> bool {
 declare_lint_pass!(StringLitAsBytes => [STRING_LIT_AS_BYTES]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for StringLitAsBytes {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
         use crate::utils::{snippet, snippet_with_applicability};
-        use syntax::ast::LitKind;
+        use rustc_ast::ast::LitKind;
 
         if_chain! {
             if let ExprKind::MethodCall(path, _, args) = &e.kind;