use rustc_hir::{
def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path,
- PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
+ PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind, UnOp,
};
use rustc_lint::{LateContext, Level, Lint, LintContext};
use rustc_middle::hir::exports::Export;
.map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
}
-/// Checks if an expression references a variable of the given name.
-pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
- if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
- if let [p] = path.segments {
- return p.ident.name == var;
- }
- }
- false
-}
-
pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
match *path {
QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
}
}
-/// Gets the name of a `Pat`, if any.
-pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
- match pat.kind {
- PatKind::Binding(.., ref spname, _) => Some(spname.name),
- PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
- PatKind::Box(p) | PatKind::Ref(p, _) => get_pat_name(&*p),
- _ => None,
- }
-}
-
pub struct ContainsName {
pub name: Symbol,
pub result: bool,
Span::new(line_start, span.hi(), span.ctxt())
}
-/// Checks if two spans begin on the same line.
-pub fn spans_on_same_line<T: LintContext>(cx: &T, left_span: Span, right_span: Span) -> bool {
- line_span(cx, left_span).lo() == line_span(cx, right_span).lo()
-}
-
/// Gets the parent node, if any.
pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
tcx.hir().parent_iter(id).next().map(|(_, node)| node)
})
}
-/// Gets the loop enclosing the given expression, if any.
-pub fn get_enclosing_loop(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+/// Gets the loop or closure enclosing the given expression, if any.
+pub fn get_enclosing_loop_or_closure(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
let map = tcx.hir();
for (_, node) in map.parent_iter(expr.hir_id) {
match node {
Node::Expr(
- e @ Expr {
- kind: ExprKind::Loop(..),
+ e
+ @
+ Expr {
+ kind: ExprKind::Loop(..) | ExprKind::Closure(..),
..
},
) => return Some(e),
did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
}
+/// Checks if an expression represents the identity function
+/// Only examines closures and `std::convert::identity`
+pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ /// Checks if a function's body represents the identity function. Looks for bodies of the form:
+ /// * `|x| x`
+ /// * `|x| return x`
+ /// * `|x| { return x }`
+ /// * `|x| { return x; }`
+ fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
+ let id = if_chain! {
+ if let [param] = func.params;
+ if let PatKind::Binding(_, id, _, _) = param.pat.kind;
+ then {
+ id
+ } else {
+ return false;
+ }
+ };
+
+ let mut expr = &func.value;
+ loop {
+ match expr.kind {
+ #[rustfmt::skip]
+ ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
+ | ExprKind::Ret(Some(e)) => expr = e,
+ #[rustfmt::skip]
+ ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
+ if_chain! {
+ if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
+ if let ExprKind::Ret(Some(ret_val)) = e.kind;
+ then {
+ expr = ret_val;
+ } else {
+ return false;
+ }
+ }
+ },
+ _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
+ }
+ }
+ }
+
+ match expr.kind {
+ ExprKind::Closure(_, _, body_id, _, _) => is_body_identity_function(cx, cx.tcx.hir().body(body_id)),
+ ExprKind::Path(ref path) => is_qpath_def_path(cx, path, expr.hir_id, &paths::CONVERT_IDENTITY),
+ _ => false,
+ }
+}
+
/// Gets the node where an expression is either used, or it's type is unified with another branch.
pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
let map = tcx.hir();
(e, count)
}
+/// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
+/// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
+pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
+ loop {
+ match expr.kind {
+ ExprKind::AddrOf(_, _, e) => expr = e,
+ ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
+ _ => break,
+ }
+ }
+ expr
+}
+
#[macro_export]
macro_rules! unwrap_cargo_metadata {
($cx: ident, $lint: ident, $deps: expr) => {{
projects / rust.git / blobdiff