1 files changed, 28 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs b/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs
new file mode 100644
index 000000000..2fe5ae9a9
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/verbose_file_reads.rs
@@ -0,0 +1,28 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::is_trait_method;
+use clippy_utils::ty::is_type_diagnostic_item;
+use rustc_hir::{Expr, ExprKind, QPath};
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::VERBOSE_FILE_READS;
+
+pub(super) const READ_TO_END_MSG: (&str, &str) = ("use of `File::read_to_end`", "consider using `fs::read` instead");
+pub(super) const READ_TO_STRING_MSG: (&str, &str) = (
+    "use of `File::read_to_string`",
+    "consider using `fs::read_to_string` instead",
+);
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    recv: &'tcx Expr<'_>,
+    (msg, help): (&str, &str),
+) {
+    if is_trait_method(cx, expr, sym::IoRead)
+        && matches!(recv.kind, ExprKind::Path(QPath::Resolved(None, _)))
+        && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty_adjusted(recv).peel_refs(), sym::File)
+    {
+        span_lint_and_help(cx, VERBOSE_FILE_READS, expr.span, msg, None, help);
+    }
+}