+use crate::consts::constant_simple;
use crate::utils;
+use crate::utils::{path_to_local_id, sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{def, Arm, Expr, ExprKind, PatKind, QPath};
+use rustc_hir::{Arm, Expr, ExprKind, Pat, PatKind};
+use rustc_lint::LintContext;
use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
declare_clippy_lint! {
/// **What it does:**
- /// Finds patterns that can be encoded more concisely with `Option::unwrap_or`.
+ /// Finds patterns that reimplement `Option::unwrap_or` or `Result::unwrap_or`.
///
/// **Why is this bad?**
/// Concise code helps focusing on behavior instead of boilerplate.
///
/// **Example:**
/// ```rust
- /// match int_optional {
+ /// let foo: Option<i32> = None;
+ /// match foo {
/// Some(v) => v,
/// None => 1,
- /// }
+ /// };
/// ```
///
/// Use instead:
/// ```rust
- /// int_optional.unwrap_or(1)
+ /// let foo: Option<i32> = None;
+ /// foo.unwrap_or(1);
/// ```
- pub LESS_CONCISE_THAN_OPTION_UNWRAP_OR,
- pedantic,
- "finds patterns that can be encoded more concisely with `Option::unwrap_or`"
+ pub MANUAL_UNWRAP_OR,
+ complexity,
+ "finds patterns that can be encoded more concisely with `Option::unwrap_or` or `Result::unwrap_or`"
}
-declare_lint_pass!(LessConciseThan => [LESS_CONCISE_THAN_OPTION_UNWRAP_OR]);
+declare_lint_pass!(ManualUnwrapOr => [MANUAL_UNWRAP_OR]);
-impl LateLintPass<'_> for LessConciseThan {
+impl LateLintPass<'_> for ManualUnwrapOr {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
- if utils::in_macro(expr.span) {
+ if in_external_macro(cx.sess(), expr.span) {
return;
}
- if lint_option_unwrap_or_case(cx, expr) {
- return;
+ lint_manual_unwrap_or(cx, expr);
+ }
+}
+
+#[derive(Copy, Clone)]
+enum Case {
+ Option,
+ Result,
+}
+
+impl Case {
+ fn unwrap_fn_path(&self) -> &str {
+ match self {
+ Case::Option => "Option::unwrap_or",
+ Case::Result => "Result::unwrap_or",
}
}
}
-fn lint_option_unwrap_or_case<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
- #[allow(clippy::needless_bool)]
- fn applicable_none_arm<'a>(arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
+fn lint_manual_unwrap_or<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
+ fn applicable_or_arm<'a>(arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
if_chain! {
if arms.len() == 2;
if arms.iter().all(|arm| arm.guard.is_none());
- if let Some((idx, none_arm)) = arms.iter().enumerate().find(|(_, arm)|
- if_chain! {
- if let PatKind::Path(ref qpath) = arm.pat.kind;
- if utils::match_qpath(qpath, &utils::paths::OPTION_NONE);
- then { true }
- else { false }
- }
+ if let Some((idx, or_arm)) = arms.iter().enumerate().find(|(_, arm)|
+ match arm.pat.kind {
+ PatKind::Path(ref some_qpath) =>
+ utils::match_qpath(some_qpath, &utils::paths::OPTION_NONE),
+ PatKind::TupleStruct(ref err_qpath, &[Pat { kind: PatKind::Wild, .. }], _) =>
+ utils::match_qpath(err_qpath, &utils::paths::RESULT_ERR),
+ _ => false,
+ }
);
- let some_arm = &arms[1 - idx];
- if let PatKind::TupleStruct(ref some_qpath, &[some_binding], _) = some_arm.pat.kind;
- if utils::match_qpath(some_qpath, &utils::paths::OPTION_SOME);
- if let PatKind::Binding(_, binding_hir_id, ..) = some_binding.kind;
- if let ExprKind::Path(QPath::Resolved(_, body_path)) = some_arm.body.kind;
- if let def::Res::Local(body_path_hir_id) = body_path.res;
- if body_path_hir_id == binding_hir_id;
- then { Some(none_arm) }
- else { None }
+ let unwrap_arm = &arms[1 - idx];
+ if let PatKind::TupleStruct(ref unwrap_qpath, &[unwrap_pat], _) = unwrap_arm.pat.kind;
+ if utils::match_qpath(unwrap_qpath, &utils::paths::OPTION_SOME)
+ || utils::match_qpath(unwrap_qpath, &utils::paths::RESULT_OK);
+ if let PatKind::Binding(_, binding_hir_id, ..) = unwrap_pat.kind;
+ if path_to_local_id(unwrap_arm.body, binding_hir_id);
+ if !utils::usage::contains_return_break_continue_macro(or_arm.body);
+ then {
+ Some(or_arm)
+ } else {
+ None
+ }
}
}
+
if_chain! {
- if !utils::usage::contains_return_break_continue_macro(expr);
- if let ExprKind::Match (match_expr, match_arms, _) = expr.kind;
- let ty = cx.typeck_results().expr_ty(match_expr);
- if utils::is_type_diagnostic_item(cx, ty, sym!(option_type));
- if let Some(none_arm) = applicable_none_arm(match_arms);
- if let Some(match_expr_snippet) = utils::snippet_opt(cx, match_expr.span);
- if let Some(none_body_snippet) = utils::snippet_opt(cx, none_arm.body.span);
- if let Some(indent) = utils::indent_of(cx, expr.span);
- then {
- let reindented_none_body =
- utils::reindent_multiline(none_body_snippet.into(), true, Some(indent));
- let eager_eval = utils::eager_or_lazy::is_eagerness_candidate(cx, none_arm.body);
- let method = if eager_eval {
- "unwrap_or"
- } else {
- "unwrap_or_else"
- };
- utils::span_lint_and_sugg(
- cx,
- LESS_CONCISE_THAN_OPTION_UNWRAP_OR, expr.span,
- "this pattern can be more concisely encoded with `Option::unwrap_or`",
- "replace with",
- format!(
- "{}.{}({}{})",
- match_expr_snippet,
- method,
- if eager_eval { ""} else { "|| " },
- reindented_none_body
- ),
- Applicability::MachineApplicable,
- );
- true
- } else { false}
+ if let ExprKind::Match(scrutinee, match_arms, _) = expr.kind;
+ let ty = cx.typeck_results().expr_ty(scrutinee);
+ if let Some(case) = if utils::is_type_diagnostic_item(cx, ty, sym::option_type) {
+ Some(Case::Option)
+ } else if utils::is_type_diagnostic_item(cx, ty, sym::result_type) {
+ Some(Case::Result)
+ } else {
+ None
+ };
+ if let Some(or_arm) = applicable_or_arm(match_arms);
+ if let Some(or_body_snippet) = utils::snippet_opt(cx, or_arm.body.span);
+ if let Some(indent) = utils::indent_of(cx, expr.span);
+ if constant_simple(cx, cx.typeck_results(), or_arm.body).is_some();
+ then {
+ let reindented_or_body =
+ utils::reindent_multiline(or_body_snippet.into(), true, Some(indent));
+ utils::span_lint_and_sugg(
+ cx,
+ MANUAL_UNWRAP_OR, expr.span,
+ &format!("this pattern reimplements `{}`", case.unwrap_fn_path()),
+ "replace with",
+ format!(
+ "{}.unwrap_or({})",
+ sugg::Sugg::hir(cx, scrutinee, "..").maybe_par(),
+ reindented_or_body,
+ ),
+ Applicability::MachineApplicable,
+ );
+ }
}
}
projects / rust.git / blobdiff