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