102 lines
3.1 KiB
Rust
102 lines
3.1 KiB
Rust
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extern crate rustc_typeck as typeck;
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use syntax::ptr::P;
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use syntax::ast::*;
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use rustc::lint::{Context, LintPass, LintArray, Lint};
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use rustc::middle::ty::{self, node_id_to_type, sty, ty_ptr, ty_rptr, mt, MethodTraitItemId};
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use rustc::middle::def::{DefTy, DefStruct, DefTrait};
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use syntax::codemap::{Span, Spanned};
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declare_lint!(pub LEN_ZERO, Warn,
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"Warn on usage of double-mut refs, e.g. '&mut &mut ...'");
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declare_lint!(pub LEN_WITHOUT_IS_EMPTY, Warn,
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"Warn on traits and impls that have .len() but not .is_empty()");
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#[derive(Copy,Clone)]
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pub struct LenZero;
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impl LintPass for LenZero {
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fn get_lints(&self) -> LintArray {
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lint_array!(LEN_ZERO, LEN_WITHOUT_IS_EMPTY)
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}
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fn check_item(&mut self, cx: &Context, item: &Item) {
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match &item.node {
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&ItemTrait(_, _, _, ref trait_items) =>
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check_trait_items(cx, item, trait_items),
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&ItemImpl(_, _, _, None, _, ref impl_items) => // only non-trait
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check_impl_items(cx, item, impl_items),
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_ => ()
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}
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}
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fn check_expr(&mut self, cx: &Context, expr: &Expr) {
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if let &ExprBinary(Spanned{node: cmp, ..}, ref left, ref right) =
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&expr.node {
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match cmp {
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BiEq => check_cmp(cx, expr.span, left, right, ""),
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BiGt | BiNe => check_cmp(cx, expr.span, left, right, "!"),
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_ => ()
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}
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}
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}
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}
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fn check_trait_items(cx: &Context, item: &Item, trait_items: &[P<TraitItem>]) {
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fn is_named_self(item: &TraitItem, name: &str) -> bool {
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item.ident.as_str() == name && item.attrs.len() == 0
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}
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if !trait_items.iter().any(|i| is_named_self(i, "is_empty")) {
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//cx.span_lint(LEN_WITHOUT_IS_EMPTY, item.span, &format!("trait {}", item.ident.as_str()));
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for i in trait_items {
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if is_named_self(i, "len") {
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cx.span_lint(LEN_WITHOUT_IS_EMPTY, i.span,
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&format!("Trait '{}' has a '.len()' method, but no \
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'.is_empty()' method. Consider adding one.",
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item.ident.as_str()));
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}
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};
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}
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}
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fn check_impl_items(cx: &Context, item: &Item, impl_items: &[P<ImplItem>]) {
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fn is_named_self(item: &ImplItem, name: &str) -> bool {
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item.ident.as_str() == name && item.attrs.len() == 0
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}
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if !impl_items.iter().any(|i| is_named_self(i, "is_empty")) {
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for i in impl_items {
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if is_named_self(i, "len") {
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cx.span_lint(LEN_WITHOUT_IS_EMPTY, i.span,
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&format!("Item '{}' has a '.len()' method, but no \
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'.is_empty()' method. Consider adding one.",
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item.ident.as_str()));
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return;
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}
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}
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}
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}
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fn check_cmp(cx: &Context, span: Span, left: &Expr, right: &Expr, empty: &str) {
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match (&left.node, &right.node) {
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(&ExprLit(ref lit), &ExprMethodCall(ref method, _, ref args)) =>
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check_len_zero(cx, span, method, args, lit, empty),
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(&ExprMethodCall(ref method, _, ref args), &ExprLit(ref lit)) =>
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check_len_zero(cx, span, method, args, lit, empty),
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_ => ()
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}
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}
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fn check_len_zero(cx: &Context, span: Span, method: &SpannedIdent,
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args: &[P<Expr>], lit: &Lit, empty: &str) {
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if let &Spanned{node: LitInt(0, _), ..} = lit {
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if method.node.as_str() == "len" && args.len() == 1 {
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cx.span_lint(LEN_ZERO, span, &format!(
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"Consider replacing the len comparison with '{}_.is_empty()' if available",
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empty))
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}
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}
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}
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