Fix review comments

Author: JonathanBrouwer

clippy_lints/src/methods/mod.rs

@@ -4395,7 +4395,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for `Read::bytes()` on an unbuffered Read type
+    /// Checks for calls to `Read::bytes` on types which don't implement `BufRead`.
     ///
     /// ### Why is this bad?
     /// The default implementation calls `read` for each byte, which can be very inefficient for data that’s not in memory, such as `File`.

clippy_lints/src/methods/unbuffered_bytes.rs

@@ -7,26 +7,25 @@ use rustc_lint::LateContext;
 use rustc_span::sym;
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>) {
-    // Retrieve the DefId of the BufRead trait
-    // FIXME: add a diagnostic item for `BufRead`
-    let Some(buf_read) = get_trait_def_id(cx.tcx, &paths::BUF_READ) else {
-        return;
-    };
+    let ty = cx.typeck_results().expr_ty_adjusted(recv);
 
-    let typ = cx.typeck_results().expr_ty_adjusted(recv);
-    if
-    // The .bytes() call is a call from the given trait
-    is_trait_method(cx, expr, sym::IoRead)
+    // If the .bytes() call is a call from the Read trait
+    if is_trait_method(cx, expr, sym::IoRead) {
+        // Retrieve the DefId of the BufRead trait
+        // FIXME: add a diagnostic item for `BufRead`
+        let Some(buf_read) = get_trait_def_id(cx.tcx, &paths::BUF_READ) else {
+            return;
+        };
         // And the implementor of the trait is not buffered
-        && !implements_trait(cx, typ, buf_read, &[])
-    {
-        span_lint_and_help(
-            cx,
-            UNBUFFERED_BYTES,
-            expr.span,
-            "calling .bytes() is very inefficient when data is not in memory",
-            None,
-            "consider using `BufReader`",
-        );
+        if !implements_trait(cx, ty, buf_read, &[]) {
+            span_lint_and_help(
+                cx,
+                UNBUFFERED_BYTES,
+                expr.span,
+                "calling .bytes() is very inefficient when data is not in memory",
+                None,
+                "consider using `BufReader`",
+            );
+        }
     }
 }