//! checks for attributes
use crate::reexport::*;
+use crate::utils::{
+ in_macro, last_line_of_span, match_def_path, opt_def_id, paths, snippet_opt, span_lint, span_lint_and_then,
+ without_block_comments,
+};
use rustc::hir::*;
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::ty::{self, TyCtxt};
use semver::Version;
use syntax::ast::{AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
use syntax::codemap::Span;
-use crate::utils::{
- in_macro, last_line_of_span, match_def_path, opt_def_id, paths, snippet_opt, span_lint, span_lint_and_then,
- without_block_comments,
-};
/// **What it does:** Checks for items annotated with `#[inline(always)]`,
/// unless the annotated function is empty or simply panics.
}
/// **What it does:** Checks for `extern crate` and `use` items annotated with
-/// lint attributes
+/// lint attributes.
+///
+/// This lint whitelists `#[allow(unused_imports)]` and `#[allow(deprecated)]` on
+/// `use` items and `#[allow(unused_imports)]` on `extern crate` items with a
+/// `#[macro_use]` attribute.
///
/// **Why is this bad?** Lint attributes have no effect on crate imports. Most
-/// likely a `!` was
-/// forgotten
+/// likely a `!` was forgotten.
///
-/// **Known problems:** Technically one might allow `unused_import` on a `use`
-/// item,
-/// but it's easier to remove the unused item.
+/// **Known problems:** None.
///
/// **Example:**
/// ```rust
+/// // Bad
/// #[deny(dead_code)]
/// extern crate foo;
-/// #[allow(unused_import)]
+/// #[forbid(dead_code)]
/// use foo::bar;
+///
+/// // Ok
+/// #[allow(unused_imports)]
+/// use foo::baz;
+/// #[allow(unused_imports)]
+/// #[macro_use]
+/// extern crate baz;
/// ```
declare_clippy_lint! {
pub USELESS_ATTRIBUTE,
check_attrs(cx, item.span, item.name, &item.attrs)
}
match item.node {
- ItemExternCrate(_) | ItemUse(_, _) => {
+ ItemKind::ExternCrate(..) | ItemKind::Use(..) => {
+ let skip_unused_imports = item.attrs.iter().any(|attr| attr.name() == "macro_use");
+
for attr in &item.attrs {
if let Some(ref lint_list) = attr.meta_item_list() {
match &*attr.name().as_str() {
"allow" | "warn" | "deny" | "forbid" => {
- // whitelist `unused_imports` and `deprecated`
+ // whitelist `unused_imports` and `deprecated` for `use` items
+ // and `unused_imports` for `extern crate` items with `macro_use`
for lint in lint_list {
- if is_word(lint, "unused_imports") || is_word(lint, "deprecated") {
- if let ItemUse(_, _) = item.node {
- return;
- }
+ match item.node {
+ ItemKind::Use(..) => if is_word(lint, "unused_imports")
+ || is_word(lint, "deprecated") {
+ return
+ },
+ ItemKind::ExternCrate(..) => if is_word(lint, "unused_imports")
+ && skip_unused_imports {
+ return
+ },
+ _ => {},
}
}
let line_span = last_line_of_span(cx, attr.span);
fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx ImplItem) {
if is_relevant_impl(cx.tcx, item) {
- check_attrs(cx, item.span, item.name, &item.attrs)
+ check_attrs(cx, item.span, item.ident.name, &item.attrs)
}
}
fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx TraitItem) {
if is_relevant_trait(cx.tcx, item) {
- check_attrs(cx, item.span, item.name, &item.attrs)
+ check_attrs(cx, item.span, item.ident.name, &item.attrs)
}
}
}
fn is_relevant_item(tcx: TyCtxt, item: &Item) -> bool {
- if let ItemFn(_, _, _, eid) = item.node {
+ if let ItemKind::Fn(_, _, _, eid) = item.node {
is_relevant_expr(tcx, tcx.body_tables(eid), &tcx.hir.body(eid).value)
} else {
true
fn is_relevant_block(tcx: TyCtxt, tables: &ty::TypeckTables, block: &Block) -> bool {
if let Some(stmt) = block.stmts.first() {
match stmt.node {
- StmtDecl(_, _) => true,
- StmtExpr(ref expr, _) | StmtSemi(ref expr, _) => is_relevant_expr(tcx, tables, expr),
+ StmtKind::Decl(_, _) => true,
+ StmtKind::Expr(ref expr, _) | StmtKind::Semi(ref expr, _) => is_relevant_expr(tcx, tables, expr),
}
} else {
block.expr.as_ref().map_or(false, |e| is_relevant_expr(tcx, tables, e))
fn is_relevant_expr(tcx: TyCtxt, tables: &ty::TypeckTables, expr: &Expr) -> bool {
match expr.node {
- ExprBlock(ref block, _) => is_relevant_block(tcx, tables, block),
- ExprRet(Some(ref e)) => is_relevant_expr(tcx, tables, e),
- ExprRet(None) | ExprBreak(_, None) => false,
- ExprCall(ref path_expr, _) => if let ExprPath(ref qpath) = path_expr.node {
+ ExprKind::Block(ref block, _) => is_relevant_block(tcx, tables, block),
+ ExprKind::Ret(Some(ref e)) => is_relevant_expr(tcx, tables, e),
+ ExprKind::Ret(None) | ExprKind::Break(_, None) => false,
+ ExprKind::Call(ref path_expr, _) => if let ExprKind::Path(ref qpath) = path_expr.node {
if let Some(fun_id) = opt_def_id(tables.qpath_def(qpath, path_expr.hir_id)) {
!match_def_path(tcx, fun_id, &paths::BEGIN_PANIC)
} else {
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