Auto merge of #3946 - rchaser53:issue-3920, r=flip1995

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

diff --git a/clippy_lints/src/vec.rs b/clippy_lints/src/vec.rs
index 39ab77c3afa1e25418e0c5652bfd814b0e1c2c3b..9b8b2372c53bc38d8a1feb675fa0ab43871f13fa 100644 (file)
--- a/clippy_lints/src/vec.rs
+++ b/clippy_lints/src/vec.rs
@@ -1,22 +1,25 @@
+use crate::consts::constant;
+use crate::utils::{higher, is_copy, snippet_with_applicability, span_lint_and_sugg};
+use if_chain::if_chain;
 use rustc::hir::*;
-use rustc::lint::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use rustc::ty::{self, Ty};
-use syntax::codemap::Span;
-use crate::utils::{higher, is_copy, snippet, span_lint_and_sugg};
-use crate::consts::constant;
+use rustc::{declare_tool_lint, lint_array};
+use rustc_errors::Applicability;
+use syntax::source_map::Span;
 
-/// **What it does:** Checks for usage of `&vec![..]` when using `&[..]` would
-/// be possible.
-///
-/// **Why is this bad?** This is less efficient.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust,ignore
-/// foo(&vec![1, 2])
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for usage of `&vec![..]` when using `&[..]` would
+    /// be possible.
+    ///
+    /// **Why is this bad?** This is less efficient.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust,ignore
+    /// foo(&vec![1, 2])
+    /// ```
     pub USELESS_VEC,
     perf,
     "useless `vec!`"
@@ -29,14 +32,18 @@ impl LintPass for Pass {
     fn get_lints(&self) -> LintArray {
         lint_array!(USELESS_VEC)
     }
+
+    fn name(&self) -> &'static str {
+        "UselessVec"
+    }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
         // search for `&vec![_]` expressions where the adjusted type is `&[_]`
         if_chain! {
-            if let ty::TyRef(_, ty, _) = cx.tables.expr_ty_adjusted(expr).sty;
-            if let ty::TySlice(..) = ty.sty;
+            if let ty::Ref(_, ty, _) = cx.tables.expr_ty_adjusted(expr).sty;
+            if let ty::Slice(..) = ty.sty;
             if let ExprKind::AddrOf(_, ref addressee) = expr.node;
             if let Some(vec_args) = higher::vec_macro(cx, addressee);
             then {
@@ -52,6 +59,11 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
             then {
                 // report the error around the `vec!` not inside `<std macros>:`
                 let span = arg.span
+                    .ctxt()
+                    .outer()
+                    .expn_info()
+                    .map(|info| info.call_site)
+                    .expect("unable to get call_site")
                     .ctxt()
                     .outer()
                     .expn_info()
@@ -64,20 +76,27 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
 }
 
 fn check_vec_macro<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, vec_args: &higher::VecArgs<'tcx>, span: Span) {
+    let mut applicability = Applicability::MachineApplicable;
     let snippet = match *vec_args {
         higher::VecArgs::Repeat(elem, len) => {
             if constant(cx, cx.tables, len).is_some() {
-                format!("&[{}; {}]", snippet(cx, elem.span, "elem"), snippet(cx, len.span, "len"))
+                format!(
+                    "&[{}; {}]",
+                    snippet_with_applicability(cx, elem.span, "elem", &mut applicability),
+                    snippet_with_applicability(cx, len.span, "len", &mut applicability)
+                )
             } else {
                 return;
             }
         },
-        higher::VecArgs::Vec(args) => if let Some(last) = args.iter().last() {
-            let span = args[0].span.to(last.span);
+        higher::VecArgs::Vec(args) => {
+            if let Some(last) = args.iter().last() {
+                let span = args[0].span.to(last.span);
 
-            format!("&[{}]", snippet(cx, span, ".."))
-        } else {
-            "&[]".into()
+                format!("&[{}]", snippet_with_applicability(cx, span, "..", &mut applicability))
+            } else {
+                "&[]".into()
+            }
         },
     };
 
@@ -88,12 +107,13 @@ fn check_vec_macro<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, vec_args: &higher::VecA
         "useless use of `vec!`",
         "you can use a slice directly",
         snippet,
+        applicability,
     );
 }
 
-/// Return the item type of the vector (ie. the `T` in `Vec<T>`).
-fn vec_type(ty: Ty) -> Ty {
-    if let ty::TyAdt(_, substs) = ty.sty {
+/// Returns the item type of the vector (i.e., the `T` in `Vec<T>`).
+fn vec_type(ty: Ty<'_>) -> Ty<'_> {
+    if let ty::Adt(_, substs) = ty.sty {
         substs.type_at(0)
     } else {
         panic!("The type of `vec!` is a not a struct?");