-
Notifications
You must be signed in to change notification settings - Fork 1.6k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Auto merge of #9258 - Serial-ATA:unused-peekable, r=Alexendoo
Add [`unused_peekable`] lint changelog: Add [`unused_peekable`] lint closes: #854
- Loading branch information
Showing
10 changed files
with
444 additions
and
1 deletion.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,225 @@ | ||
| use clippy_utils::diagnostics::span_lint_and_help; | ||
| use clippy_utils::ty::{match_type, peel_mid_ty_refs_is_mutable}; | ||
| use clippy_utils::{fn_def_id, is_trait_method, path_to_local_id, paths, peel_ref_operators}; | ||
| use rustc_ast::Mutability; | ||
| use rustc_hir::intravisit::{walk_expr, Visitor}; | ||
| use rustc_hir::lang_items::LangItem; | ||
| use rustc_hir::{Block, Expr, ExprKind, HirId, Local, Node, PatKind, PathSegment, StmtKind}; | ||
| use rustc_lint::{LateContext, LateLintPass}; | ||
| use rustc_session::{declare_lint_pass, declare_tool_lint}; | ||
| use rustc_span::sym; | ||
|
|
||
| declare_clippy_lint! { | ||
| /// ### What it does | ||
| /// Checks for the creation of a `peekable` iterator that is never `.peek()`ed | ||
| /// | ||
| /// ### Why is this bad? | ||
| /// Creating a peekable iterator without using any of its methods is likely a mistake, | ||
| /// or just a leftover after a refactor. | ||
| /// | ||
| /// ### Example | ||
| /// ```rust | ||
| /// let collection = vec![1, 2, 3]; | ||
| /// let iter = collection.iter().peekable(); | ||
| /// | ||
| /// for item in iter { | ||
| /// // ... | ||
| /// } | ||
| /// ``` | ||
| /// | ||
| /// Use instead: | ||
| /// ```rust | ||
| /// let collection = vec![1, 2, 3]; | ||
| /// let iter = collection.iter(); | ||
| /// | ||
| /// for item in iter { | ||
| /// // ... | ||
| /// } | ||
| /// ``` | ||
| #[clippy::version = "1.64.0"] | ||
| pub UNUSED_PEEKABLE, | ||
| suspicious, | ||
| "creating a peekable iterator without using any of its methods" | ||
| } | ||
|
|
||
| declare_lint_pass!(UnusedPeekable => [UNUSED_PEEKABLE]); | ||
|
|
||
| impl<'tcx> LateLintPass<'tcx> for UnusedPeekable { | ||
| fn check_block(&mut self, cx: &LateContext<'tcx>, block: &Block<'tcx>) { | ||
| // Don't lint `Peekable`s returned from a block | ||
| if let Some(expr) = block.expr | ||
| && let Some(ty) = cx.typeck_results().expr_ty_opt(peel_ref_operators(cx, expr)) | ||
| && match_type(cx, ty, &paths::PEEKABLE) | ||
| { | ||
| return; | ||
| } | ||
|
|
||
| for (idx, stmt) in block.stmts.iter().enumerate() { | ||
| if !stmt.span.from_expansion() | ||
| && let StmtKind::Local(local) = stmt.kind | ||
| && let PatKind::Binding(_, binding, ident, _) = local.pat.kind | ||
| && let Some(init) = local.init | ||
| && !init.span.from_expansion() | ||
| && let Some(ty) = cx.typeck_results().expr_ty_opt(init) | ||
| && let (ty, _, Mutability::Mut) = peel_mid_ty_refs_is_mutable(ty) | ||
| && match_type(cx, ty, &paths::PEEKABLE) | ||
| { | ||
| let mut vis = PeekableVisitor::new(cx, binding); | ||
|
|
||
| if idx + 1 == block.stmts.len() && block.expr.is_none() { | ||
| return; | ||
| } | ||
|
|
||
| for stmt in &block.stmts[idx..] { | ||
| vis.visit_stmt(stmt); | ||
| } | ||
|
|
||
| if let Some(expr) = block.expr { | ||
| vis.visit_expr(expr); | ||
| } | ||
|
|
||
| if !vis.found_peek_call { | ||
| span_lint_and_help( | ||
| cx, | ||
| UNUSED_PEEKABLE, | ||
| ident.span, | ||
| "`peek` never called on `Peekable` iterator", | ||
| None, | ||
| "consider removing the call to `peekable`" | ||
| ); | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| struct PeekableVisitor<'a, 'tcx> { | ||
| cx: &'a LateContext<'tcx>, | ||
| expected_hir_id: HirId, | ||
| found_peek_call: bool, | ||
| } | ||
|
|
||
| impl<'a, 'tcx> PeekableVisitor<'a, 'tcx> { | ||
| fn new(cx: &'a LateContext<'tcx>, expected_hir_id: HirId) -> Self { | ||
| Self { | ||
| cx, | ||
| expected_hir_id, | ||
| found_peek_call: false, | ||
| } | ||
| } | ||
| } | ||
|
|
||
| impl<'tcx> Visitor<'_> for PeekableVisitor<'_, 'tcx> { | ||
| fn visit_expr(&mut self, ex: &'_ Expr<'_>) { | ||
| if self.found_peek_call { | ||
| return; | ||
| } | ||
|
|
||
| if path_to_local_id(ex, self.expected_hir_id) { | ||
| for (_, node) in self.cx.tcx.hir().parent_iter(ex.hir_id) { | ||
| match node { | ||
| Node::Expr(expr) => { | ||
| match expr.kind { | ||
| // some_function(peekable) | ||
| // | ||
| // If the Peekable is passed to a function, stop | ||
| ExprKind::Call(_, args) => { | ||
| if let Some(func_did) = fn_def_id(self.cx, expr) | ||
| && let Ok(into_iter_did) = self | ||
| .cx | ||
| .tcx | ||
| .lang_items() | ||
| .require(LangItem::IntoIterIntoIter) | ||
| && func_did == into_iter_did | ||
| { | ||
| // Probably a for loop desugar, stop searching | ||
| return; | ||
| } | ||
|
|
||
| if args.iter().any(|arg| { | ||
| matches!(arg.kind, ExprKind::Path(_)) && arg_is_mut_peekable(self.cx, arg) | ||
| }) { | ||
| self.found_peek_call = true; | ||
| return; | ||
| } | ||
| }, | ||
| // Catch anything taking a Peekable mutably | ||
| ExprKind::MethodCall( | ||
| PathSegment { | ||
| ident: method_name_ident, | ||
| .. | ||
| }, | ||
| [self_arg, remaining_args @ ..], | ||
| _, | ||
| ) => { | ||
| let method_name = method_name_ident.name.as_str(); | ||
|
|
||
| // `Peekable` methods | ||
| if matches!(method_name, "peek" | "peek_mut" | "next_if" | "next_if_eq") | ||
| && arg_is_mut_peekable(self.cx, self_arg) | ||
| { | ||
| self.found_peek_call = true; | ||
| return; | ||
| } | ||
|
|
||
| // foo.some_method() excluding Iterator methods | ||
| if remaining_args.iter().any(|arg| arg_is_mut_peekable(self.cx, arg)) | ||
| && !is_trait_method(self.cx, expr, sym::Iterator) | ||
| { | ||
| self.found_peek_call = true; | ||
| return; | ||
| } | ||
|
|
||
| // foo.by_ref(), keep checking for `peek` | ||
| if method_name == "by_ref" { | ||
| continue; | ||
| } | ||
|
|
||
| return; | ||
| }, | ||
| ExprKind::AddrOf(_, Mutability::Mut, _) | ExprKind::Unary(..) | ExprKind::DropTemps(_) => { | ||
| }, | ||
| ExprKind::AddrOf(_, Mutability::Not, _) => return, | ||
| _ => { | ||
| self.found_peek_call = true; | ||
| return; | ||
| }, | ||
| } | ||
| }, | ||
| Node::Local(Local { init: Some(init), .. }) => { | ||
| if arg_is_mut_peekable(self.cx, init) { | ||
| self.found_peek_call = true; | ||
| return; | ||
| } | ||
|
|
||
| break; | ||
| }, | ||
| Node::Stmt(stmt) => match stmt.kind { | ||
| StmtKind::Expr(_) | StmtKind::Semi(_) => {}, | ||
| _ => { | ||
| self.found_peek_call = true; | ||
| return; | ||
| }, | ||
| }, | ||
| Node::Block(_) => {}, | ||
| _ => { | ||
| break; | ||
| }, | ||
| } | ||
| } | ||
| } | ||
|
|
||
| walk_expr(self, ex); | ||
| } | ||
| } | ||
|
|
||
| fn arg_is_mut_peekable(cx: &LateContext<'_>, arg: &Expr<'_>) -> bool { | ||
| if let Some(ty) = cx.typeck_results().expr_ty_opt(arg) | ||
| && let (ty, _, Mutability::Mut) = peel_mid_ty_refs_is_mutable(ty) | ||
| && match_type(cx, ty, &paths::PEEKABLE) | ||
| { | ||
| true | ||
| } else { | ||
| false | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.