diff --git a/clippy_lints/src/read_zero_byte_vec.rs b/clippy_lints/src/read_zero_byte_vec.rs index acd840401c6b..b8d4e7c4651d 100644 --- a/clippy_lints/src/read_zero_byte_vec.rs +++ b/clippy_lints/src/read_zero_byte_vec.rs @@ -1,6 +1,6 @@ use clippy_utils::diagnostics::{span_lint_hir, span_lint_hir_and_then}; use clippy_utils::higher::{VecInitKind, get_vec_init_kind}; -use clippy_utils::source::snippet; +use clippy_utils::source::{indent_of, snippet}; use clippy_utils::{get_enclosing_block, sym}; use rustc_errors::Applicability; @@ -83,10 +83,12 @@ impl<'tcx> LateLintPass<'tcx> for ReadZeroByteVec { expr.span, "reading zero byte data to `Vec`", |diag| { + let span = first_stmt_containing_expr(cx, expr).map_or(expr.span, |stmt| stmt.span); + let indent = indent_of(cx, span).unwrap_or(0); diag.span_suggestion( - expr.span, + span.shrink_to_lo(), "try", - format!("{}.resize({len}, 0); {}", ident, snippet(cx, expr.span, "..")), + format!("{ident}.resize({len}, 0);\n{}", " ".repeat(indent)), applicability, ); }, @@ -100,14 +102,15 @@ impl<'tcx> LateLintPass<'tcx> for ReadZeroByteVec { expr.span, "reading zero byte data to `Vec`", |diag| { + let span = first_stmt_containing_expr(cx, expr).map_or(expr.span, |stmt| stmt.span); + let indent = indent_of(cx, span).unwrap_or(0); diag.span_suggestion( - expr.span, + span.shrink_to_lo(), "try", format!( - "{}.resize({}, 0); {}", - ident, + "{ident}.resize({}, 0);\n{}", snippet(cx, e.span, ".."), - snippet(cx, expr.span, "..") + " ".repeat(indent) ), applicability, ); @@ -130,6 +133,16 @@ impl<'tcx> LateLintPass<'tcx> for ReadZeroByteVec { } } +fn first_stmt_containing_expr<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx hir::Stmt<'tcx>> { + cx.tcx.hir_parent_iter(expr.hir_id).find_map(|(_, node)| { + if let hir::Node::Stmt(stmt) = node { + Some(stmt) + } else { + None + } + }) +} + struct ReadVecVisitor<'tcx> { local_id: HirId, read_zero_expr: Option<&'tcx Expr<'tcx>>, diff --git a/tests/ui/read_zero_byte_vec.rs b/tests/ui/read_zero_byte_vec.rs index 938d61b68607..720276cb5548 100644 --- a/tests/ui/read_zero_byte_vec.rs +++ b/tests/ui/read_zero_byte_vec.rs @@ -120,3 +120,30 @@ fn allow_works(mut f: F) { } fn main() {} + +fn issue15575() -> usize { + use std::io::Read; + use std::net::TcpListener; + + let listener = TcpListener::bind("127.0.0.1:9010").unwrap(); + let mut stream_and_addr = listener.accept().unwrap(); + let mut buf = Vec::with_capacity(32); + let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + //~^ read_zero_byte_vec + + let cap = 1000; + let mut buf = Vec::with_capacity(cap); + let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + //~^ read_zero_byte_vec + + let cap = 1000; + let mut buf = Vec::with_capacity(cap); + let num_bytes_received = { stream_and_addr.0.read(&mut buf) }.unwrap(); + //~^ read_zero_byte_vec + + use std::fs::File; + let mut f = File::open("foo.txt").unwrap(); + let mut data = Vec::with_capacity(100); + f.read(&mut data).unwrap() + //~^ read_zero_byte_vec +} diff --git a/tests/ui/read_zero_byte_vec.stderr b/tests/ui/read_zero_byte_vec.stderr index 8f255bc87ab8..8dd74592e4c1 100644 --- a/tests/ui/read_zero_byte_vec.stderr +++ b/tests/ui/read_zero_byte_vec.stderr @@ -2,16 +2,27 @@ error: reading zero byte data to `Vec` --> tests/ui/read_zero_byte_vec.rs:22:5 | LL | f.read_exact(&mut data).unwrap(); - | ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `data.resize(20, 0); f.read_exact(&mut data)` + | ^^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D clippy::read-zero-byte-vec` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::read_zero_byte_vec)]` +help: try + | +LL ~ data.resize(20, 0); +LL ~ f.read_exact(&mut data).unwrap(); + | error: reading zero byte data to `Vec` --> tests/ui/read_zero_byte_vec.rs:28:5 | LL | f.read_exact(&mut data2)?; - | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `data2.resize(cap, 0); f.read_exact(&mut data2)` + | ^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try + | +LL ~ data2.resize(cap, 0); +LL ~ f.read_exact(&mut data2)?; + | error: reading zero byte data to `Vec` --> tests/ui/read_zero_byte_vec.rs:33:5 @@ -67,5 +78,53 @@ error: reading zero byte data to `Vec` LL | r.read_exact(&mut data2).await.unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^ -error: aborting due to 11 previous errors +error: reading zero byte data to `Vec` + --> tests/ui/read_zero_byte_vec.rs:131:30 + | +LL | let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try + | +LL ~ buf.resize(32, 0); +LL ~ let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + | + +error: reading zero byte data to `Vec` + --> tests/ui/read_zero_byte_vec.rs:136:30 + | +LL | let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try + | +LL ~ buf.resize(cap, 0); +LL ~ let num_bytes_received = stream_and_addr.0.read(&mut buf).unwrap(); + | + +error: reading zero byte data to `Vec` + --> tests/ui/read_zero_byte_vec.rs:141:32 + | +LL | let num_bytes_received = { stream_and_addr.0.read(&mut buf) }.unwrap(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: try + | +LL ~ buf.resize(cap, 0); +LL ~ let num_bytes_received = { stream_and_addr.0.read(&mut buf) }.unwrap(); + | + +error: reading zero byte data to `Vec` + --> tests/ui/read_zero_byte_vec.rs:147:5 + | +LL | f.read(&mut data).unwrap() + | ^^^^^^^^^^^^^^^^^ + | +help: try + | +LL ~ data.resize(100, 0); +LL ~ f.read(&mut data).unwrap() + | + +error: aborting due to 15 previous errors