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Merge pull request #637 from mcarton/debug

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Lint usage of `Debug`-based formatting
This commit is contained in:
llogiq 2016-02-12 12:18:15 +01:00
commit 9ee462625b
10 changed files with 148 additions and 117 deletions
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1
README.md
View file

@ -119,6 +119,7 @@ name
[unstable_as_slice](https://github.com/Manishearth/rust-clippy/wiki#unstable_as_slice) | warn | as_slice is not stable and can be replaced by & v[..]see https://github.com/rust-lang/rust/issues/27729
[unused_collect](https://github.com/Manishearth/rust-clippy/wiki#unused_collect) | warn | `collect()`ing an iterator without using the result; this is usually better written as a for loop
[unused_lifetimes](https://github.com/Manishearth/rust-clippy/wiki#unused_lifetimes) | warn | unused lifetimes in function definitions
[use_debug](https://github.com/Manishearth/rust-clippy/wiki#use_debug) | allow | use `Debug`-based formatting
[used_underscore_binding](https://github.com/Manishearth/rust-clippy/wiki#used_underscore_binding) | warn | using a binding which is prefixed with an underscore
[useless_transmute](https://github.com/Manishearth/rust-clippy/wiki#useless_transmute) | warn | transmutes that have the same to and from types
[useless_vec](https://github.com/Manishearth/rust-clippy/wiki#useless_vec) | warn | useless `vec!`

86
src/consts.rs
View file

@ -6,12 +6,10 @@ use rustc::middle::def::PathResolution;
use rustc::middle::def::Def;
use rustc_front::hir::*;
use syntax::ptr::P;
use std::char;
use std::cmp::PartialOrd;
use std::cmp::Ordering::{self, Greater, Less, Equal};
use std::rc::Rc;
use std::ops::Deref;
use std::fmt;
use syntax::ast::Lit_;
use syntax::ast::LitIntType;
@ -173,90 +171,6 @@ impl PartialOrd for Constant {
}
}
fn format_byte(fmt: &mut fmt::Formatter, b: u8) -> fmt::Result {
if b == b'\\' {
write!(fmt, "\\\\")
} else if 0x20 <= b && b <= 0x7e {
write!(fmt, "{}", char::from_u32(b as u32).expect("all u8 are valid char"))
} else if b == 0x0a {
write!(fmt, "\\n")
} else if b == 0x0d {
write!(fmt, "\\r")
} else {
write!(fmt, "\\x{:02x}", b)
}
}
impl fmt::Display for Constant {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
match *self {
Constant::Str(ref s, _) => write!(fmt, "{:?}", s),
Constant::Byte(ref b) => {
write!(fmt, "b'")
.and_then(|_| format_byte(fmt, *b))
.and_then(|_| write!(fmt, "'"))
}
Constant::Binary(ref bs) => {
try!(write!(fmt, "b\""));
for b in bs.iter() {
try!(format_byte(fmt, *b));
}
write!(fmt, "\"")
}
Constant::Char(ref c) => write!(fmt, "'{}'", c),
Constant::Int(ref i, ref ity) => {
let (sign, suffix) = match *ity {
LitIntType::SignedIntLit(ref sity, ref sign) => {
(if let Sign::Minus = *sign {
"-"
} else {
""
},
sity.ty_to_string())
}
LitIntType::UnsignedIntLit(ref uity) => ("", uity.ty_to_string()),
LitIntType::UnsuffixedIntLit(ref sign) => {
(if let Sign::Minus = *sign {
"-"
} else {
""
},
"".into())
}
};
write!(fmt, "{}{}{}", sign, i, suffix)
}
Constant::Float(ref s, ref fw) => {
let suffix = match *fw {
FloatWidth::Fw32 => "f32",
FloatWidth::Fw64 => "f64",
FloatWidth::FwAny => "",
};
write!(fmt, "{}{}", s, suffix)
}
Constant::Bool(ref b) => write!(fmt, "{}", b),
Constant::Repeat(ref c, ref n) => write!(fmt, "[{}; {}]", c, n),
Constant::Vec(ref v) => {
write!(fmt,
"[{}]",
v.iter()
.map(|i| format!("{}", i))
.collect::<Vec<_>>()
.join(", "))
}
Constant::Tuple(ref t) => {
write!(fmt,
"({})",
t.iter()
.map(|i| format!("{}", i))
.collect::<Vec<_>>()
.join(", "))
}
}
}
}
fn lit_to_constant(lit: &Lit_) -> Constant {
match *lit {
Lit_::LitStr(ref is, style) => Constant::Str(is.to_string(), style),

1
src/lib.rs
View file

@ -170,6 +170,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
mut_mut::MUT_MUT,
mutex_atomic::MUTEX_INTEGER,
print::PRINT_STDOUT,
print::USE_DEBUG,
shadow::SHADOW_REUSE,
shadow::SHADOW_SAME,
shadow::SHADOW_UNRELATED,

45
src/loops.rs
View file

@ -1,11 +1,12 @@
use rustc::lint::*;
use rustc_front::hir::*;
use reexport::*;
use rustc_front::intravisit::{Visitor, walk_expr, walk_block, walk_decl};
use rustc::middle::ty;
use rustc::middle::def::Def;
use consts::{constant_simple, Constant};
use rustc::front::map::Node::NodeBlock;
use rustc::lint::*;
use rustc::middle::const_eval::EvalHint::ExprTypeChecked;
use rustc::middle::const_eval::{ConstVal, eval_const_expr_partial};
use rustc::middle::def::Def;
use rustc::middle::ty;
use rustc_front::hir::*;
use rustc_front::intravisit::{Visitor, walk_expr, walk_block, walk_decl};
use std::borrow::Cow;
use std::collections::{HashSet, HashMap};
@ -421,22 +422,36 @@ fn check_for_loop_reverse_range(cx: &LateContext, arg: &Expr, expr: &Expr) {
// if this for loop is iterating over a two-sided range...
if let ExprRange(Some(ref start_expr), Some(ref stop_expr)) = arg.node {
// ...and both sides are compile-time constant integers...
if let Some(start_idx @ Constant::Int(..)) = constant_simple(start_expr) {
if let Some(stop_idx @ Constant::Int(..)) = constant_simple(stop_expr) {
if let Ok(start_idx) = eval_const_expr_partial(&cx.tcx, start_expr, ExprTypeChecked, None) {
if let Ok(stop_idx) = eval_const_expr_partial(&cx.tcx, stop_expr, ExprTypeChecked, None) {
// ...and the start index is greater than the stop index,
// this loop will never run. This is often confusing for developers
// who think that this will iterate from the larger value to the
// smaller value.
if start_idx > stop_idx {
span_help_and_lint(cx,
let (sup, eq) = match (start_idx, stop_idx) {
(ConstVal::Int(start_idx), ConstVal::Int(stop_idx)) => (start_idx > stop_idx, start_idx == stop_idx),
(ConstVal::Uint(start_idx), ConstVal::Uint(stop_idx)) => (start_idx > stop_idx, start_idx == stop_idx),
_ => (false, false),
};
if sup {
let start_snippet = snippet(cx, start_expr.span, "_");
let stop_snippet = snippet(cx, stop_expr.span, "_");
span_lint_and_then(cx,
REVERSE_RANGE_LOOP,
expr.span,
"this range is empty so this for loop will never run",
&format!("Consider using `({}..{}).rev()` if you are attempting to iterate \
over this range in reverse",
stop_idx,
start_idx));
} else if start_idx == stop_idx {
|db| {
db.span_suggestion(expr.span,
"consider using the following if \
you are attempting to iterate \
over this range in reverse",
format!("({}..{}).rev()` ",
stop_snippet,
start_snippet));
});
} else if eq {
// if they are equal, it's also problematic - this loop
// will never run.
span_lint(cx,

16
src/misc.rs
View file

@ -11,7 +11,7 @@ use rustc::middle::const_eval::eval_const_expr_partial;
use rustc::middle::const_eval::EvalHint::ExprTypeChecked;
use utils::{get_item_name, match_path, snippet, get_parent_expr, span_lint};
use utils::{span_help_and_lint, walk_ptrs_ty, is_integer_literal, implements_trait};
use utils::{span_lint_and_then, walk_ptrs_ty, is_integer_literal, implements_trait};
/// **What it does:** This lint checks for function arguments and let bindings denoted as `ref`.
///
@ -62,16 +62,22 @@ impl LateLintPass for TopLevelRefPass {
let Some(ref init) = l.init
], {
let tyopt = if let Some(ref ty) = l.ty {
format!(": {:?} ", ty)
format!(": {}", snippet(cx, ty.span, "_"))
} else {
"".to_owned()
};
span_help_and_lint(cx,
span_lint_and_then(cx,
TOPLEVEL_REF_ARG,
l.pat.span,
"`ref` on an entire `let` pattern is discouraged, take a reference with & instead",
&format!("try `let {} {}= &{};`", snippet(cx, i.span, "_"),
tyopt, snippet(cx, init.span, "_"))
|db| {
db.span_suggestion(s.span,
"try",
format!("let {}{} = &{};",
snippet(cx, i.span, "_"),
tyopt,
snippet(cx, init.span, "_")));
}
);
}
};

48
src/print.rs
View file

@ -1,6 +1,8 @@
use rustc::lint::*;
use rustc_front::hir::*;
use utils::{IO_PRINT_PATH, is_expn_of, match_path, span_lint};
use rustc::front::map::Node::{NodeItem, NodeImplItem};
use utils::{FMT_ARGUMENTV1_NEW_PATH, DEBUG_FMT_METHOD_PATH, IO_PRINT_PATH};
use utils::{is_expn_of, match_path, span_lint};
/// **What it does:** This lint warns whenever you print on *stdout*. The purpose of this lint is to catch debugging remnants.
///
@ -16,21 +18,36 @@ declare_lint! {
"printing on stdout"
}
/// **What it does:** This lint warns whenever you use `Debug` formatting. The purpose of this lint is to catch debugging remnants.
///
/// **Why is this bad?** The purpose of the `Debug` trait is to facilitate debugging Rust code. It
/// should not be used in in user-facing output.
///
/// **Example:** `println!("{:?}", foo);`
declare_lint! {
pub USE_DEBUG,
Allow,
"use `Debug`-based formatting"
}
#[derive(Copy, Clone, Debug)]
pub struct PrintLint;
impl LintPass for PrintLint {
fn get_lints(&self) -> LintArray {
lint_array!(PRINT_STDOUT)
lint_array!(PRINT_STDOUT, USE_DEBUG)
}
}
impl LateLintPass for PrintLint {
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
if let ExprCall(ref fun, _) = expr.node {
if let ExprCall(ref fun, ref args) = expr.node {
if let ExprPath(_, ref path) = fun.node {
// Search for `std::io::_print(..)` which is unique in a
// `print!` expansion.
if match_path(path, &IO_PRINT_PATH) {
if let Some(span) = is_expn_of(cx, expr.span, "print") {
// `println!` uses `print!`.
let (span, name) = match is_expn_of(cx, span, "println") {
Some(span) => (span, "println"),
None => (span, "print"),
@ -39,7 +56,32 @@ impl LateLintPass for PrintLint {
span_lint(cx, PRINT_STDOUT, span, &format!("use of `{}!`", name));
}
}
// Search for something like
// `::std::fmt::ArgumentV1::new(__arg0, ::std::fmt::Debug::fmt)`
else if args.len() == 2 && match_path(path, &FMT_ARGUMENTV1_NEW_PATH) {
if let ExprPath(None, ref path) = args[1].node {
if match_path(path, &DEBUG_FMT_METHOD_PATH) &&
!is_in_debug_impl(cx, expr) &&
is_expn_of(cx, expr.span, "panic").is_none() {
span_lint(cx, USE_DEBUG, args[0].span, "use of `Debug`-based formatting");
}
}
}
}
}
}
}
fn is_in_debug_impl(cx: &LateContext, expr: &Expr) -> bool {
let map = &cx.tcx.map;
if let Some(NodeImplItem(item)) = map.find(map.get_parent(expr.id)) { // `fmt` method
if let Some(NodeItem(item)) = map.find(map.get_parent(item.id)) { // `Debug` impl
if let ItemImpl(_, _, _, Some(ref tr), _, _) = item.node {
return match_path(&tr.path, &["Debug"]);
}
}
}
false
}

2
src/utils.rs
View file

@ -26,8 +26,10 @@ pub const BTREEMAP_PATH: [&'static str; 4] = ["collections", "btree", "map", "BT
pub const CLONE_PATH: [&'static str; 3] = ["clone", "Clone", "clone"];
pub const CLONE_TRAIT_PATH: [&'static str; 2] = ["clone", "Clone"];
pub const COW_PATH: [&'static str; 3] = ["collections", "borrow", "Cow"];
pub const DEBUG_FMT_METHOD_PATH: [&'static str; 4] = ["std", "fmt", "Debug", "fmt"];
pub const DEFAULT_TRAIT_PATH: [&'static str; 3] = ["core", "default", "Default"];
pub const DROP_PATH: [&'static str; 3] = ["core", "mem", "drop"];
pub const FMT_ARGUMENTV1_NEW_PATH: [&'static str; 4] = ["std", "fmt", "ArgumentV1", "new"];
pub const HASHMAP_ENTRY_PATH: [&'static str; 5] = ["std", "collections", "hash", "map", "Entry"];
pub const HASHMAP_PATH: [&'static str; 5] = ["std", "collections", "hash", "map", "HashMap"];
pub const HASH_PATH: [&'static str; 2] = ["hash", "Hash"];

22
tests/compile-fail/for_loop.rs
View file

@ -65,7 +65,7 @@ fn for_loop_over_option_and_result() {
break;
}
// while let false positive for Option
// while let false positive for Result
while let Ok(x) = result {
println!("{}", x);
break;
@ -85,8 +85,10 @@ impl Unrelated {
#[deny(needless_range_loop, explicit_iter_loop, iter_next_loop, reverse_range_loop, explicit_counter_loop)]
#[deny(unused_collect)]
#[allow(linkedlist,shadow_unrelated,unnecessary_mut_passed, cyclomatic_complexity)]
#[allow(linkedlist, shadow_unrelated, unnecessary_mut_passed, cyclomatic_complexity)]
fn main() {
const MAX_LEN: usize = 42;
let mut vec = vec![1, 2, 3, 4];
let vec2 = vec![1, 2, 3, 4];
for i in 0..vec.len() {
@ -111,6 +113,11 @@ fn main() {
println!("{}", vec[i]);
}
for i in 0..MAX_LEN {
//~^ ERROR `i` is only used to index `vec`. Consider using `for item in vec.iter().take(MAX_LEN)`
println!("{}", vec[i]);
}
for i in 5..10 {
//~^ ERROR `i` is only used to index `vec`. Consider using `for item in vec.iter().take(10).skip(5)`
println!("{}", vec[i]);
@ -126,7 +133,16 @@ fn main() {
println!("{} {}", vec[i], i);
}
for i in 10..0 { //~ERROR this range is empty so this for loop will never run
for i in 10..0 {
//~^ERROR this range is empty so this for loop will never run
//~|HELP consider
//~|SUGGESTION (0..10).rev()
println!("{}", i);
}
for i in MAX_LEN..0 { //~ERROR this range is empty so this for loop will never run
//~|HELP consider
//~|SUGGESTION (0..MAX_LEN).rev()
println!("{}", i);
}

32
tests/compile-fail/print.rs
View file

@ -1,11 +1,41 @@
#![feature(plugin)]
#![plugin(clippy)]
#![deny(print_stdout, use_debug)]
#[deny(print_stdout)]
use std::fmt::{Debug, Display, Formatter, Result};
#[allow(dead_code)]
struct Foo;
impl Display for Foo {
fn fmt(&self, f: &mut Formatter) -> Result {
write!(f, "{:?}", 43.1415)
//~^ ERROR use of `Debug`-based formatting
}
}
impl Debug for Foo {
fn fmt(&self, f: &mut Formatter) -> Result {
// ok, we can use `Debug` formatting in `Debug` implementations
write!(f, "{:?}", 42.718)
}
}
fn main() {
println!("Hello"); //~ERROR use of `println!`
print!("Hello"); //~ERROR use of `print!`
print!("Hello {}", "World"); //~ERROR use of `print!`
print!("Hello {:?}", "World");
//~^ ERROR use of `print!`
//~| ERROR use of `Debug`-based formatting
print!("Hello {:#?}", "#orld");
//~^ ERROR use of `print!`
//~| ERROR use of `Debug`-based formatting
assert_eq!(42, 1337);
vec![1, 2];
}

12
tests/compile-fail/toplevel_ref_arg.rs
View file

@ -15,11 +15,15 @@ fn main() {
let y = |ref x| { println!("{:?}", x) };
y(1u8);
let ref x = 1; //~ ERROR `ref` on an entire `let` pattern is discouraged
//~^ HELP try `let x = &1;`
let ref x = 1;
//~^ ERROR `ref` on an entire `let` pattern is discouraged
//~| HELP try
//~| SUGGESTION let x = &1;
let ref y = (&1, 2); //~ ERROR `ref` on an entire `let` pattern is discouraged
//~^ HELP try `let y = &(&1, 2);`
let ref y : (&_, u8) = (&1, 2);
//~^ ERROR `ref` on an entire `let` pattern is discouraged
//~| HELP try
//~| SUGGESTION let y: (&_, u8) = &(&1, 2);
let (ref x, _) = (1,2); // okay, not top level
println!("The answer is {}.", x);