+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
+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, 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.
- ///
- /// **Why is this bad?** Question mark usage is more idiomatic.
+ /// ### What it does
+ /// Checks for expressions that could be replaced by the question mark operator.
///
- /// **Known problems:** None
+ /// ### Why is this bad?
+ /// Question mark usage is more idiomatic.
///
- /// **Example:**
+ /// ### Example
/// ```ignore
/// if option.is_none() {
/// return None;
/// ```
///
/// 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 Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
+ if let ExprKind::MethodCall(segment, _, args, _) = &cond.kind;
if segment.ident.name == sym!(is_none);
- if Self::expression_returns_none(cx, body);
+ if Self::expression_returns_none(cx, then);
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<String> = None;
- if let Some(else_) = else_ {
+ if let Some(else_inner) = r#else {
if_chain! {
- if let ExprKind::Block(block, None) = &else_.node;
- if block.stmts.len() == 0;
+ if let ExprKind::Block(block, None) = &else_inner.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 Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) }) = higher::IfLet::hir(cx, expr);
+ if Self::is_option(cx, let_expr);
+
+ if let PatKind::TupleStruct(ref path1, fields, None) = let_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(ref block, None) = if_then.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 Self::expression_returns_none(cx, if_else);
+ then {
+ let mut applicability = Applicability::MachineApplicable;
+ let receiver_str = snippet_with_applicability(cx, let_expr.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<Expr>> {
+ 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);
// 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);
}
}
}
-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);
}
}
projects / rust.git / blobdiff