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 clippy_utils::{eq_expr_value, is_lang_ctor, path_to_local, path_to_local_id, peel_blocks, peel_blocks_with_stmt};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::LangItem::{OptionNone, OptionSome};
-use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, PatKind, StmtKind};
+use rustc_hir::LangItem::{OptionNone, OptionSome, ResultOk};
+use rustc_hir::{BindingAnnotation, Expr, ExprKind, PatKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
/// ```ignore
/// option?;
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub QUESTION_MARK,
style,
"checks for expressions that could be replaced by the question mark operator"
/// }
/// ```
///
+ /// ```ignore
+ /// if result.is_err() {
+ /// return result;
+ /// }
+ /// ```
+ ///
/// 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_or_err_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>) {
if_chain! {
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, then);
+ if let ExprKind::MethodCall(segment, args, _) = &cond.kind;
if let Some(subject) = args.get(0);
- if Self::is_option(cx, subject);
-
+ if (Self::option_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_none)) ||
+ (Self::result_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_err));
then {
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_inner) = r#else {
- if_chain! {
- if let ExprKind::Block(block, None) = &else_inner.kind;
- if block.stmts.is_empty();
- if let Some(block_expr) = &block.expr;
- if eq_expr_value(cx, subject, block_expr);
- then {
- replacement = Some(format!("Some({}?)", receiver_str));
- }
+ if eq_expr_value(cx, subject, peel_blocks(else_inner)) {
+ replacement = Some(format!("Some({}?)", receiver_str));
}
} else if Self::moves_by_default(cx, subject)
&& !matches!(subject.kind, ExprKind::Call(..) | ExprKind::MethodCall(..))
}
}
- fn check_if_let_some_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) {
+ fn check_if_let_some_or_err_and_early_return(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 (Self::option_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, OptionSome)) ||
+ (Self::result_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, ResultOk));
+
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) = if_then.kind;
- if block.stmts.is_empty();
- if let Some(trailing_expr) = &block.expr;
- if path_to_local_id(trailing_expr, bind_id);
-
- if Self::expression_returns_none(cx, if_else);
+ if path_to_local_id(peel_blocks(if_then), bind_id);
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 { "" },
- );
+ let replacement = format!("{}{}?", receiver_str, if by_ref { ".as_ref()" } else { "" },);
span_lint_and_sugg(
cx,
}
}
+ fn result_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool {
+ Self::is_result(cx, expr) && Self::expression_returns_unmodified_err(cx, nested_expr, expr)
+ }
+
+ fn option_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool {
+ Self::is_option(cx, expr) && Self::expression_returns_none(cx, nested_expr)
+ }
+
fn moves_by_default(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
let expr_ty = cx.typeck_results().expr_ty(expression);
is_type_diagnostic_item(cx, expr_ty, sym::Option)
}
- 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);
- }
+ fn is_result(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
+ let expr_ty = cx.typeck_results().expr_ty(expression);
+
+ is_type_diagnostic_item(cx, expr_ty, sym::Result)
+ }
- false
- },
+ fn expression_returns_none(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
+ match peel_blocks_with_stmt(expression).kind {
ExprKind::Ret(Some(expr)) => Self::expression_returns_none(cx, expr),
ExprKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
_ => false,
}
}
- 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(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.is_empty();
- if let Some(ExprKind::Ret(Some(ret_expr))) = block.expr.as_ref().map(|e| &e.kind);
- then {
- return Some(ret_expr);
- }
+ fn expression_returns_unmodified_err(cx: &LateContext<'_>, expr: &Expr<'_>, cond_expr: &Expr<'_>) -> bool {
+ match peel_blocks_with_stmt(expr).kind {
+ ExprKind::Ret(Some(ret_expr)) => Self::expression_returns_unmodified_err(cx, ret_expr, cond_expr),
+ ExprKind::Path(_) => path_to_local(expr).is_some() && path_to_local(expr) == path_to_local(cond_expr),
+ _ => false,
}
-
- None
}
}
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);
+ Self::check_is_none_or_err_and_early_return(cx, expr);
+ Self::check_if_let_some_or_err_and_early_return(cx, expr);
}
}
projects / rust.git / blobdiff