X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fquestion_mark.rs;h=d66bac5224360baea2acc2729d8717a42f9dc19b;hb=ebf88c9734246a790305f6faaba0bf8e3f150dff;hp=7e3453e260c4da2f1bb49a3b919ad89021e079c9;hpb=f18f81d6a6527419485a7cfcfa2f6794794bdcc4;p=rust.git diff --git a/clippy_lints/src/question_mark.rs b/clippy_lints/src/question_mark.rs index 7e3453e260c..d66bac52243 100644 --- a/clippy_lints/src/question_mark.rs +++ b/clippy_lints/src/question_mark.rs @@ -1,14 +1,16 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::is_lang_ctor; +use clippy_utils::source::snippet_with_applicability; +use clippy_utils::sugg::Sugg; +use clippy_utils::ty::is_type_diagnostic_item; +use clippy_utils::{eq_expr_value, path_to_local_id}; use if_chain::if_chain; -use rustc::hir::def::{DefKind, Res}; -use rustc::hir::ptr::P; -use rustc::hir::*; -use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; -use rustc::{declare_lint_pass, declare_tool_lint}; use rustc_errors::Applicability; - -use crate::utils::paths::*; -use crate::utils::sugg::Sugg; -use crate::utils::{higher, match_def_path, match_type, span_lint_and_then, SpanlessEq}; +use rustc_hir::LangItem::{OptionNone, OptionSome}; +use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, MatchSource, PatKind, 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 expressions that could be replaced by the question mark operator. @@ -46,97 +48,126 @@ impl QuestionMark { /// ``` /// /// If it matches, it will suggest to use the question mark operator instead - fn check_is_none_and_early_return_none(cx: &LateContext<'_, '_>, expr: &Expr) { + fn check_is_none_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) { if_chain! { - if let Some((if_expr, body, else_)) = higher::if_block(&expr); - if let ExprKind::MethodCall(segment, _, args) = &if_expr.node; + if let ExprKind::If(if_expr, body, else_) = &expr.kind; + if let ExprKind::MethodCall(segment, _, args, _) = &if_expr.kind; if segment.ident.name == sym!(is_none); if Self::expression_returns_none(cx, body); if let Some(subject) = args.get(0); if Self::is_option(cx, subject); then { - let receiver_str = &Sugg::hir(cx, subject, ".."); + let mut applicability = Applicability::MachineApplicable; + let receiver_str = &Sugg::hir_with_applicability(cx, subject, "..", &mut applicability); let mut replacement: Option = None; if let Some(else_) = else_ { if_chain! { - if let ExprKind::Block(block, None) = &else_.node; - if block.stmts.len() == 0; + if let ExprKind::Block(block, None) = &else_.kind; + if block.stmts.is_empty(); if let Some(block_expr) = &block.expr; - if SpanlessEq::new(cx).ignore_fn().eq_expr(subject, block_expr); + if eq_expr_value(cx, subject, block_expr); then { replacement = Some(format!("Some({}?)", receiver_str)); } } - } else if Self::moves_by_default(cx, subject) { - replacement = Some(format!("{}.as_ref()?;", receiver_str)); + } else if Self::moves_by_default(cx, subject) + && !matches!(subject.kind, ExprKind::Call(..) | ExprKind::MethodCall(..)) + { + replacement = Some(format!("{}.as_ref()?;", receiver_str)); } else { - replacement = Some(format!("{}?;", receiver_str)); + replacement = Some(format!("{}?;", receiver_str)); } if let Some(replacement_str) = replacement { - span_lint_and_then( + span_lint_and_sugg( cx, QUESTION_MARK, expr.span, "this block may be rewritten with the `?` operator", - |db| { - db.span_suggestion( - expr.span, - "replace_it_with", - replacement_str, - Applicability::MaybeIncorrect, // snippet - ); - } - ) - } + "replace it with", + replacement_str, + applicability, + ); + } } } } - fn moves_by_default(cx: &LateContext<'_, '_>, expression: &Expr) -> bool { - let expr_ty = cx.tables.expr_ty(expression); + fn check_if_let_some_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) { + if_chain! { + if let ExprKind::Match(subject, arms, source) = &expr.kind; + if *source == MatchSource::IfLetDesugar { contains_else_clause: true }; + if Self::is_option(cx, subject); + + if let PatKind::TupleStruct(path1, fields, None) = &arms[0].pat.kind; + if is_lang_ctor(cx, path1, OptionSome); + if let PatKind::Binding(annot, bind_id, _, _) = fields[0].kind; + let by_ref = matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut); + + if let ExprKind::Block(block, None) = &arms[0].body.kind; + if block.stmts.is_empty(); + if let Some(trailing_expr) = &block.expr; + if path_to_local_id(trailing_expr, bind_id); - !expr_ty.is_copy_modulo_regions(cx.tcx, cx.param_env, expression.span) + if let PatKind::Wild = arms[1].pat.kind; + if Self::expression_returns_none(cx, arms[1].body); + then { + let mut applicability = Applicability::MachineApplicable; + let receiver_str = snippet_with_applicability(cx, subject.span, "..", &mut applicability); + let replacement = format!( + "{}{}?", + receiver_str, + if by_ref { ".as_ref()" } else { "" }, + ); + + span_lint_and_sugg( + cx, + QUESTION_MARK, + expr.span, + "this if-let-else may be rewritten with the `?` operator", + "replace it with", + replacement, + applicability, + ); + } + } } - fn is_option(cx: &LateContext<'_, '_>, expression: &Expr) -> bool { - let expr_ty = cx.tables.expr_ty(expression); + fn moves_by_default(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { + let expr_ty = cx.typeck_results().expr_ty(expression); - match_type(cx, expr_ty, &OPTION) + !expr_ty.is_copy_modulo_regions(cx.tcx.at(expression.span), cx.param_env) } - fn expression_returns_none(cx: &LateContext<'_, '_>, expression: &Expr) -> bool { - match expression.node { - ExprKind::Block(ref block, _) => { - if let Some(return_expression) = Self::return_expression(block) { - return Self::expression_returns_none(cx, &return_expression); - } + fn is_option(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { + let expr_ty = cx.typeck_results().expr_ty(expression); - false - }, - ExprKind::Ret(Some(ref expr)) => Self::expression_returns_none(cx, expr), - ExprKind::Path(ref qp) => { - if let Res::Def(DefKind::Ctor(def::CtorOf::Variant, def::CtorKind::Const), def_id) = - cx.tables.qpath_res(qp, expression.hir_id) - { - return match_def_path(cx, def_id, &OPTION_NONE); + is_type_diagnostic_item(cx, expr_ty, sym::option_type) + } + + fn expression_returns_none(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { + match expression.kind { + ExprKind::Block(block, _) => { + if let Some(return_expression) = Self::return_expression(block) { + return Self::expression_returns_none(cx, return_expression); } false }, + ExprKind::Ret(Some(expr)) => Self::expression_returns_none(cx, expr), + ExprKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone), _ => false, } } - fn return_expression(block: &Block) -> Option<&P> { + fn return_expression<'tcx>(block: &Block<'tcx>) -> Option<&'tcx Expr<'tcx>> { // Check if last expression is a return statement. Then, return the expression if_chain! { if block.stmts.len() == 1; if let Some(expr) = block.stmts.iter().last(); - if let StmtKind::Semi(ref expr) = expr.node; - if let ExprKind::Ret(ref ret_expr) = expr.node; - if let &Some(ref ret_expr) = ret_expr; + if let StmtKind::Semi(expr) = expr.kind; + if let ExprKind::Ret(Some(ret_expr)) = expr.kind; then { return Some(ret_expr); @@ -145,8 +176,8 @@ fn return_expression(block: &Block) -> Option<&P> { // Check for `return` without a semicolon. if_chain! { - if block.stmts.len() == 0; - if let Some(ExprKind::Ret(Some(ret_expr))) = block.expr.as_ref().map(|e| &e.node); + if block.stmts.is_empty(); + if let Some(ExprKind::Ret(Some(ret_expr))) = block.expr.as_ref().map(|e| &e.kind); then { return Some(ret_expr); } @@ -156,8 +187,9 @@ fn return_expression(block: &Block) -> Option<&P> { } } -impl<'a, 'tcx> LateLintPass<'a, 'tcx> for QuestionMark { - fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) { +impl<'tcx> LateLintPass<'tcx> for QuestionMark { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { Self::check_is_none_and_early_return_none(cx, expr); + Self::check_if_let_some_and_early_return_none(cx, expr); } }