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split clippy into lints, plugin and cargo-clippy

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Oliver Schneider 2016-05-24 18:25:25 +02:00
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commit bf227f4729
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160
src/strings.rs
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@ -1,160 +0,0 @@
//! This lint catches both string addition and string addition + assignment
//!
//! Note that since we have two lints where one subsumes the other, we try to
//! disable the subsumed lint unless it has a higher level
use rustc::hir::*;
use rustc::lint::*;
use syntax::codemap::Spanned;
use utils::SpanlessEq;
use utils::{match_type, paths, span_lint, span_lint_and_then, walk_ptrs_ty, get_parent_expr};
/// **What it does:** This lint matches code of the form `x = x + y` (without `let`!).
///
/// **Why is this bad?** It's not really bad, but some people think that the `.push_str(_)` method is more readable.
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```
/// let mut x = "Hello".to_owned();
/// x = x + ", World";
/// ```
declare_lint! {
pub STRING_ADD_ASSIGN,
Allow,
"using `x = x + ..` where x is a `String`; suggests using `push_str()` instead"
}
/// **What it does:** The `string_add` lint matches all instances of `x + _` where `x` is of type `String`, but only if [`string_add_assign`](#string_add_assign) does *not* match.
///
/// **Why is this bad?** It's not bad in and of itself. However, this particular `Add` implementation is asymmetric (the other operand need not be `String`, but `x` does), while addition as mathematically defined is symmetric, also the `String::push_str(_)` function is a perfectly good replacement. Therefore some dislike it and wish not to have it in their code.
///
/// That said, other people think that String addition, having a long tradition in other languages is actually fine, which is why we decided to make this particular lint `allow` by default.
///
/// **Known problems:** None
///
/// **Example:**
///
/// ```
/// let x = "Hello".to_owned();
/// x + ", World"
/// ```
declare_lint! {
pub STRING_ADD,
Allow,
"using `x + ..` where x is a `String`; suggests using `push_str()` instead"
}
/// **What it does:** This lint matches the `as_bytes` method called on string
/// literals that contain only ascii characters.
///
/// **Why is this bad?** Byte string literals (e.g. `b"foo"`) can be used instead. They are shorter but less discoverable than `as_bytes()`.
///
/// **Example:**
///
/// ```
/// let bs = "a byte string".as_bytes();
/// ```
declare_lint! {
pub STRING_LIT_AS_BYTES,
Warn,
"calling `as_bytes` on a string literal; suggests using a byte string literal instead"
}
#[derive(Copy, Clone)]
pub struct StringAdd;
impl LintPass for StringAdd {
fn get_lints(&self) -> LintArray {
lint_array!(STRING_ADD, STRING_ADD_ASSIGN)
}
}
impl LateLintPass for StringAdd {
fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
if let ExprBinary(Spanned { node: BiAdd, .. }, ref left, _) = e.node {
if is_string(cx, left) {
if let Allow = cx.current_level(STRING_ADD_ASSIGN) {
// the string_add_assign is allow, so no duplicates
} else {
let parent = get_parent_expr(cx, e);
if let Some(ref p) = parent {
if let ExprAssign(ref target, _) = p.node {
// avoid duplicate matches
if SpanlessEq::new(cx).eq_expr(target, left) {
return;
}
}
}
}
span_lint(cx,
STRING_ADD,
e.span,
"you added something to a string. Consider using `String::push_str()` instead");
}
} else if let ExprAssign(ref target, ref src) = e.node {
if is_string(cx, target) && is_add(cx, src, target) {
span_lint(cx,
STRING_ADD_ASSIGN,
e.span,
"you assigned the result of adding something to this string. Consider using \
`String::push_str()` instead");
}
}
}
}
fn is_string(cx: &LateContext, e: &Expr) -> bool {
match_type(cx, walk_ptrs_ty(cx.tcx.expr_ty(e)), &paths::STRING)
}
fn is_add(cx: &LateContext, src: &Expr, target: &Expr) -> bool {
match src.node {
ExprBinary(Spanned { node: BiAdd, .. }, ref left, _) => SpanlessEq::new(cx).eq_expr(target, left),
ExprBlock(ref block) => {
block.stmts.is_empty() && block.expr.as_ref().map_or(false, |expr| is_add(cx, expr, target))
}
_ => false,
}
}
#[derive(Copy, Clone)]
pub struct StringLitAsBytes;
impl LintPass for StringLitAsBytes {
fn get_lints(&self) -> LintArray {
lint_array!(STRING_LIT_AS_BYTES)
}
}
impl LateLintPass for StringLitAsBytes {
fn check_expr(&mut self, cx: &LateContext, e: &Expr) {
use std::ascii::AsciiExt;
use syntax::ast::LitKind;
use utils::{snippet, in_macro};
if let ExprMethodCall(ref name, _, ref args) = e.node {
if name.node.as_str() == "as_bytes" {
if let ExprLit(ref lit) = args[0].node {
if let LitKind::Str(ref lit_content, _) = lit.node {
if lit_content.chars().all(|c| c.is_ascii()) && !in_macro(cx, args[0].span) {
span_lint_and_then(cx,
STRING_LIT_AS_BYTES,
e.span,
"calling `as_bytes()` on a string literal",
|db| {
let sugg = format!("b{}", snippet(cx, args[0].span, r#""foo""#));
db.span_suggestion(e.span,
"consider using a byte string literal instead",
sugg);
});
}
}
}
}
}
}
}