rustc_lint: only query `typeck_tables_of` when a lint needs it.

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

diff --git a/clippy_lints/src/indexing_slicing.rs b/clippy_lints/src/indexing_slicing.rs
index ac9442e9607822fd1525363bb46942d63a7d8fc3..c5e4abc94a8a669e9962a6715f3e1279dcd54474 100644 (file)
--- a/clippy_lints/src/indexing_slicing.rs
+++ b/clippy_lints/src/indexing_slicing.rs
@@ -2,11 +2,11 @@
 
 use crate::consts::{constant, Constant};
 use crate::utils::{higher, span_lint, span_lint_and_help};
-use rustc::ty;
-use rustc_hir::*;
+use rustc_ast::ast::RangeLimits;
+use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use syntax::ast::RangeLimits;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for out of bounds array indexing with a constant
@@ -88,11 +88,15 @@
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for IndexingSlicing {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
         if let ExprKind::Index(ref array, ref index) = &expr.kind {
-            let ty = cx.tables.expr_ty(array);
+            let ty = cx.tables().expr_ty(array);
             if let Some(range) = higher::range(cx, index) {
                 // Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
                 if let ty::Array(_, s) = ty.kind {
-                    let size: u128 = s.eval_usize(cx.tcx, cx.param_env).into();
+                    let size: u128 = if let Some(size) = s.try_eval_usize(cx.tcx, cx.param_env) {
+                        size.into()
+                    } else {
+                        return;
+                    };
 
                     let const_range = to_const_range(cx, range, size);
 
@@ -134,12 +138,12 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
                     (None, None) => return, // [..] is ok.
                 };
 
-                span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic.", help_msg);
+                span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic.", None, help_msg);
             } else {
                 // Catchall non-range index, i.e., [n] or [n << m]
                 if let ty::Array(..) = ty.kind {
                     // Index is a constant uint.
-                    if let Some(..) = constant(cx, cx.tables, index) {
+                    if let Some(..) = constant(cx, cx.tables(), index) {
                         // Let rustc's `const_err` lint handle constant `usize` indexing on arrays.
                         return;
                     }
@@ -150,6 +154,7 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
                     INDEXING_SLICING,
                     expr.span,
                     "indexing may panic.",
+                    None,
                     "Consider using `.get(n)` or `.get_mut(n)` instead",
                 );
             }
@@ -164,14 +169,14 @@ fn to_const_range<'a, 'tcx>(
     range: higher::Range<'_>,
     array_size: u128,
 ) -> (Option<u128>, Option<u128>) {
-    let s = range.start.map(|expr| constant(cx, cx.tables, expr).map(|(c, _)| c));
+    let s = range.start.map(|expr| constant(cx, cx.tables(), expr).map(|(c, _)| c));
     let start = match s {
         Some(Some(Constant::Int(x))) => Some(x),
         Some(_) => None,
         None => Some(0),
     };
 
-    let e = range.end.map(|expr| constant(cx, cx.tables, expr).map(|(c, _)| c));
+    let e = range.end.map(|expr| constant(cx, cx.tables(), expr).map(|(c, _)| c));
     let end = match e {
         Some(Some(Constant::Int(x))) => {
             if range.limits == RangeLimits::Closed {