-use crate::utils::SpanlessEq;
-use crate::utils::{get_parent_expr, is_allowed, match_type, paths, span_lint, span_lint_and_sugg, walk_ptrs_ty};
+use rustc::declare_lint_pass;
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
use syntax::source_map::Spanned;
-/// **What it does:** Checks for string appends 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:**
-///
-/// ```rust
-/// let mut x = "Hello".to_owned();
-/// x = x + ", World";
-/// ```
+use if_chain::if_chain;
+
+use crate::utils::SpanlessEq;
+use crate::utils::{
+ get_parent_expr, in_macro, is_allowed, match_type, paths, span_lint, span_lint_and_sugg, walk_ptrs_ty,
+};
+
declare_clippy_lint! {
+ /// **What it does:** Checks for string appends 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:**
+ ///
+ /// ```rust
+ /// let mut x = "Hello".to_owned();
+ /// x = x + ", World";
+ /// ```
pub STRING_ADD_ASSIGN,
pedantic,
"using `x = x + ..` where x is a `String` instead of `push_str()`"
}
-/// **What it does:** Checks for 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:**
-///
-/// ```rust
-/// let x = "Hello".to_owned();
-/// x + ", World"
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for 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:**
+ ///
+ /// ```rust
+ /// let x = "Hello".to_owned();
+ /// x + ", World";
+ /// ```
pub STRING_ADD,
restriction,
"using `x + ..` where x is a `String` instead of `push_str()`"
}
-/// **What it does:** Checks for 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()`.
-///
-/// **Known Problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// let bs = "a byte string".as_bytes();
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for 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()`.
+ ///
+ /// **Known Problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// let bs = "a byte string".as_bytes();
+ /// ```
pub STRING_LIT_AS_BYTES,
style,
"calling `as_bytes` on a string literal instead of using a byte string literal"
}
-#[derive(Copy, Clone)]
-pub struct StringAdd;
-
-impl LintPass for StringAdd {
- fn get_lints(&self) -> LintArray {
- lint_array!(STRING_ADD, STRING_ADD_ASSIGN)
- }
-
- fn name(&self) -> &'static str {
- "StringAdd"
- }
-}
+declare_lint_pass!(StringAdd => [STRING_ADD, STRING_ADD_ASSIGN]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for StringAdd {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
+ if in_macro(e.span) {
+ return;
+ }
+
if let ExprKind::Binary(
Spanned {
node: BinOpKind::Add, ..
},
ref left,
_,
- ) = e.node
+ ) = e.kind
{
if is_string(cx, left) {
- if !is_allowed(cx, STRING_ADD_ASSIGN, e.id) {
+ if !is_allowed(cx, STRING_ADD_ASSIGN, e.hir_id) {
let parent = get_parent_expr(cx, e);
if let Some(p) = parent {
- if let ExprKind::Assign(ref target, _) = p.node {
+ if let ExprKind::Assign(ref target, _) = p.kind {
// avoid duplicate matches
if SpanlessEq::new(cx).eq_expr(target, left) {
return;
"you added something to a string. Consider using `String::push_str()` instead",
);
}
- } else if let ExprKind::Assign(ref target, ref src) = e.node {
+ } else if let ExprKind::Assign(ref target, ref src) = e.kind {
if is_string(cx, target) && is_add(cx, src, target) {
span_lint(
cx,
}
fn is_add(cx: &LateContext<'_, '_>, src: &Expr, target: &Expr) -> bool {
- match src.node {
+ match src.kind {
ExprKind::Binary(
Spanned {
node: BinOpKind::Add, ..
}
}
-#[derive(Copy, Clone)]
-pub struct StringLitAsBytes;
-
-impl LintPass for StringLitAsBytes {
- fn get_lints(&self) -> LintArray {
- lint_array!(STRING_LIT_AS_BYTES)
- }
+// Max length a b"foo" string can take
+const MAX_LENGTH_BYTE_STRING_LIT: usize = 32;
- fn name(&self) -> &'static str {
- "StringLiteralAsBytes"
- }
-}
+declare_lint_pass!(StringLitAsBytes => [STRING_LIT_AS_BYTES]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for StringLitAsBytes {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
- use crate::utils::{in_macro, snippet, snippet_with_applicability};
- use syntax::ast::{LitKind, StrStyle};
+ use crate::utils::{snippet, snippet_with_applicability};
+ use syntax::ast::LitKind;
- if let ExprKind::MethodCall(ref path, _, ref args) = e.node {
- if path.ident.name == "as_bytes" {
- if let ExprKind::Lit(ref lit) = args[0].node {
- if let LitKind::Str(ref lit_content, style) = lit.node {
- let callsite = snippet(cx, args[0].span.source_callsite(), r#""foo""#);
- let expanded = if let StrStyle::Raw(n) = style {
- let term = (0..n).map(|_| '#').collect::<String>();
- format!("r{0}\"{1}\"{0}", term, lit_content.as_str())
- } else {
- format!("\"{}\"", lit_content.as_str())
- };
- let mut applicability = Applicability::MachineApplicable;
- if callsite.starts_with("include_str!") {
- span_lint_and_sugg(
- cx,
- STRING_LIT_AS_BYTES,
- e.span,
- "calling `as_bytes()` on `include_str!(..)`",
- "consider using `include_bytes!(..)` instead",
- snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability).replacen(
- "include_str",
- "include_bytes",
- 1,
- ),
- applicability,
- );
- } else if callsite == expanded
- && lit_content.as_str().chars().all(|c| c.is_ascii())
- && !in_macro(args[0].span)
- {
- span_lint_and_sugg(
- cx,
- STRING_LIT_AS_BYTES,
- e.span,
- "calling `as_bytes()` on a string literal",
- "consider using a byte string literal instead",
- format!(
- "b{}",
- snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability)
- ),
- applicability,
- );
- }
- }
+ if_chain! {
+ if let ExprKind::MethodCall(path, _, args) = &e.kind;
+ if path.ident.name == sym!(as_bytes);
+ if let ExprKind::Lit(lit) = &args[0].kind;
+ if let LitKind::Str(lit_content, _) = &lit.node;
+ then {
+ let callsite = snippet(cx, args[0].span.source_callsite(), r#""foo""#);
+ let mut applicability = Applicability::MachineApplicable;
+ if callsite.starts_with("include_str!") {
+ span_lint_and_sugg(
+ cx,
+ STRING_LIT_AS_BYTES,
+ e.span,
+ "calling `as_bytes()` on `include_str!(..)`",
+ "consider using `include_bytes!(..)` instead",
+ snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability).replacen(
+ "include_str",
+ "include_bytes",
+ 1,
+ ),
+ applicability,
+ );
+ } else if lit_content.as_str().is_ascii()
+ && lit_content.as_str().len() <= MAX_LENGTH_BYTE_STRING_LIT
+ && !args[0].span.from_expansion()
+ {
+ span_lint_and_sugg(
+ cx,
+ STRING_LIT_AS_BYTES,
+ e.span,
+ "calling `as_bytes()` on a string literal",
+ "consider using a byte string literal instead",
+ format!(
+ "b{}",
+ snippet_with_applicability(cx, args[0].span, r#""foo""#, &mut applicability)
+ ),
+ applicability,
+ );
}
}
}