--- /dev/null
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::{indent_of, snippet_block, snippet_opt, snippet_with_applicability};
+use clippy_utils::sugg::Sugg;
+use clippy_utils::{get_parent_expr, is_refutable, peel_blocks};
+use rustc_errors::Applicability;
+use rustc_hir::{Arm, Expr, ExprKind, Local, Node, PatKind};
+use rustc_lint::LateContext;
+
+use super::MATCH_SINGLE_BINDING;
+
+#[allow(clippy::too_many_lines)]
+pub(crate) fn check<'a>(cx: &LateContext<'a>, ex: &Expr<'a>, arms: &[Arm<'_>], expr: &Expr<'_>) {
+ if expr.span.from_expansion() || arms.len() != 1 || is_refutable(cx, arms[0].pat) {
+ return;
+ }
+
+ // HACK:
+ // This is a hack to deal with arms that are excluded by macros like `#[cfg]`. It is only used here
+ // to prevent false positives as there is currently no better way to detect if code was excluded by
+ // a macro. See PR #6435
+ if_chain! {
+ if let Some(match_snippet) = snippet_opt(cx, expr.span);
+ if let Some(arm_snippet) = snippet_opt(cx, arms[0].span);
+ if let Some(ex_snippet) = snippet_opt(cx, ex.span);
+ let rest_snippet = match_snippet.replace(&arm_snippet, "").replace(&ex_snippet, "");
+ if rest_snippet.contains("=>");
+ then {
+ // The code it self contains another thick arrow "=>"
+ // -> Either another arm or a comment
+ return;
+ }
+ }
+
+ let matched_vars = ex.span;
+ let bind_names = arms[0].pat.span;
+ let match_body = peel_blocks(arms[0].body);
+ let mut snippet_body = if match_body.span.from_expansion() {
+ Sugg::hir_with_macro_callsite(cx, match_body, "..").to_string()
+ } else {
+ snippet_block(cx, match_body.span, "..", Some(expr.span)).to_string()
+ };
+
+ // Do we need to add ';' to suggestion ?
+ match match_body.kind {
+ ExprKind::Block(block, _) => {
+ // macro + expr_ty(body) == ()
+ if block.span.from_expansion() && cx.typeck_results().expr_ty(match_body).is_unit() {
+ snippet_body.push(';');
+ }
+ },
+ _ => {
+ // expr_ty(body) == ()
+ if cx.typeck_results().expr_ty(match_body).is_unit() {
+ snippet_body.push(';');
+ }
+ },
+ }
+
+ let mut applicability = Applicability::MaybeIncorrect;
+ match arms[0].pat.kind {
+ PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
+ // If this match is in a local (`let`) stmt
+ let (target_span, sugg) = if let Some(parent_let_node) = opt_parent_let(cx, ex) {
+ (
+ parent_let_node.span,
+ format!(
+ "let {} = {};\n{}let {} = {};",
+ snippet_with_applicability(cx, bind_names, "..", &mut applicability),
+ snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
+ " ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
+ snippet_with_applicability(cx, parent_let_node.pat.span, "..", &mut applicability),
+ snippet_body
+ ),
+ )
+ } else {
+ // If we are in closure, we need curly braces around suggestion
+ let mut indent = " ".repeat(indent_of(cx, ex.span).unwrap_or(0));
+ let (mut cbrace_start, mut cbrace_end) = ("".to_string(), "".to_string());
+ if let Some(parent_expr) = get_parent_expr(cx, expr) {
+ if let ExprKind::Closure(..) = parent_expr.kind {
+ cbrace_end = format!("\n{}}}", indent);
+ // Fix body indent due to the closure
+ indent = " ".repeat(indent_of(cx, bind_names).unwrap_or(0));
+ cbrace_start = format!("{{\n{}", indent);
+ }
+ }
+ // If the parent is already an arm, and the body is another match statement,
+ // we need curly braces around suggestion
+ let parent_node_id = cx.tcx.hir().get_parent_node(expr.hir_id);
+ if let Node::Arm(arm) = &cx.tcx.hir().get(parent_node_id) {
+ if let ExprKind::Match(..) = arm.body.kind {
+ cbrace_end = format!("\n{}}}", indent);
+ // Fix body indent due to the match
+ indent = " ".repeat(indent_of(cx, bind_names).unwrap_or(0));
+ cbrace_start = format!("{{\n{}", indent);
+ }
+ }
+ (
+ expr.span,
+ format!(
+ "{}let {} = {};\n{}{}{}",
+ cbrace_start,
+ snippet_with_applicability(cx, bind_names, "..", &mut applicability),
+ snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
+ indent,
+ snippet_body,
+ cbrace_end
+ ),
+ )
+ };
+ span_lint_and_sugg(
+ cx,
+ MATCH_SINGLE_BINDING,
+ target_span,
+ "this match could be written as a `let` statement",
+ "consider using `let` statement",
+ sugg,
+ applicability,
+ );
+ },
+ PatKind::Wild => {
+ if ex.can_have_side_effects() {
+ let indent = " ".repeat(indent_of(cx, expr.span).unwrap_or(0));
+ let sugg = format!(
+ "{};\n{}{}",
+ snippet_with_applicability(cx, ex.span, "..", &mut applicability),
+ indent,
+ snippet_body
+ );
+ span_lint_and_sugg(
+ cx,
+ MATCH_SINGLE_BINDING,
+ expr.span,
+ "this match could be replaced by its scrutinee and body",
+ "consider using the scrutinee and body instead",
+ sugg,
+ applicability,
+ );
+ } else {
+ span_lint_and_sugg(
+ cx,
+ MATCH_SINGLE_BINDING,
+ expr.span,
+ "this match could be replaced by its body itself",
+ "consider using the match body instead",
+ snippet_body,
+ Applicability::MachineApplicable,
+ );
+ }
+ },
+ _ => (),
+ }
+}
+
+/// Returns true if the `ex` match expression is in a local (`let`) statement
+fn opt_parent_let<'a>(cx: &LateContext<'a>, ex: &Expr<'a>) -> Option<&'a Local<'a>> {
+ let map = &cx.tcx.hir();
+ if_chain! {
+ if let Some(Node::Expr(parent_arm_expr)) = map.find(map.get_parent_node(ex.hir_id));
+ if let Some(Node::Local(parent_let_expr)) = map.find(map.get_parent_node(parent_arm_expr.hir_id));
+ then {
+ return Some(parent_let_expr);
+ }
+ }
+ None
+}
use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
-use clippy_utils::source::{indent_of, snippet, snippet_block, snippet_opt, snippet_with_applicability};
+use clippy_utils::source::{snippet, snippet_with_applicability};
use clippy_utils::sugg::Sugg;
-use clippy_utils::{
- get_parent_expr, is_refutable, is_wild, meets_msrv, msrvs, path_to_local_id, peel_blocks, strip_pat_refs,
-};
+use clippy_utils::{is_wild, meets_msrv, msrvs, path_to_local_id, peel_blocks, strip_pat_refs};
use core::iter::once;
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Node, Pat, PatKind, QPath};
+use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Pat, PatKind, QPath};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty;
use rustc_semver::RustcVersion;
mod match_bool;
mod match_like_matches;
mod match_same_arms;
+mod match_single_binding;
mod match_wild_enum;
mod match_wild_err_arm;
mod overlapping_arms;
if self.infallible_destructuring_match_linted {
self.infallible_destructuring_match_linted = false;
} else {
- check_match_single_binding(cx, ex, arms, expr);
+ match_single_binding::check(cx, ex, arms, expr);
}
}
if let ExprKind::Match(ex, arms, _) = expr.kind {
}
}
-#[allow(clippy::too_many_lines)]
-fn check_match_single_binding<'a>(cx: &LateContext<'a>, ex: &Expr<'a>, arms: &[Arm<'_>], expr: &Expr<'_>) {
- if expr.span.from_expansion() || arms.len() != 1 || is_refutable(cx, arms[0].pat) {
- return;
- }
-
- // HACK:
- // This is a hack to deal with arms that are excluded by macros like `#[cfg]`. It is only used here
- // to prevent false positives as there is currently no better way to detect if code was excluded by
- // a macro. See PR #6435
- if_chain! {
- if let Some(match_snippet) = snippet_opt(cx, expr.span);
- if let Some(arm_snippet) = snippet_opt(cx, arms[0].span);
- if let Some(ex_snippet) = snippet_opt(cx, ex.span);
- let rest_snippet = match_snippet.replace(&arm_snippet, "").replace(&ex_snippet, "");
- if rest_snippet.contains("=>");
- then {
- // The code it self contains another thick arrow "=>"
- // -> Either another arm or a comment
- return;
- }
- }
-
- let matched_vars = ex.span;
- let bind_names = arms[0].pat.span;
- let match_body = peel_blocks(arms[0].body);
- let mut snippet_body = if match_body.span.from_expansion() {
- Sugg::hir_with_macro_callsite(cx, match_body, "..").to_string()
- } else {
- snippet_block(cx, match_body.span, "..", Some(expr.span)).to_string()
- };
-
- // Do we need to add ';' to suggestion ?
- match match_body.kind {
- ExprKind::Block(block, _) => {
- // macro + expr_ty(body) == ()
- if block.span.from_expansion() && cx.typeck_results().expr_ty(match_body).is_unit() {
- snippet_body.push(';');
- }
- },
- _ => {
- // expr_ty(body) == ()
- if cx.typeck_results().expr_ty(match_body).is_unit() {
- snippet_body.push(';');
- }
- },
- }
-
- let mut applicability = Applicability::MaybeIncorrect;
- match arms[0].pat.kind {
- PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
- // If this match is in a local (`let`) stmt
- let (target_span, sugg) = if let Some(parent_let_node) = opt_parent_let(cx, ex) {
- (
- parent_let_node.span,
- format!(
- "let {} = {};\n{}let {} = {};",
- snippet_with_applicability(cx, bind_names, "..", &mut applicability),
- snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
- " ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
- snippet_with_applicability(cx, parent_let_node.pat.span, "..", &mut applicability),
- snippet_body
- ),
- )
- } else {
- // If we are in closure, we need curly braces around suggestion
- let mut indent = " ".repeat(indent_of(cx, ex.span).unwrap_or(0));
- let (mut cbrace_start, mut cbrace_end) = ("".to_string(), "".to_string());
- if let Some(parent_expr) = get_parent_expr(cx, expr) {
- if let ExprKind::Closure(..) = parent_expr.kind {
- cbrace_end = format!("\n{}}}", indent);
- // Fix body indent due to the closure
- indent = " ".repeat(indent_of(cx, bind_names).unwrap_or(0));
- cbrace_start = format!("{{\n{}", indent);
- }
- }
- // If the parent is already an arm, and the body is another match statement,
- // we need curly braces around suggestion
- let parent_node_id = cx.tcx.hir().get_parent_node(expr.hir_id);
- if let Node::Arm(arm) = &cx.tcx.hir().get(parent_node_id) {
- if let ExprKind::Match(..) = arm.body.kind {
- cbrace_end = format!("\n{}}}", indent);
- // Fix body indent due to the match
- indent = " ".repeat(indent_of(cx, bind_names).unwrap_or(0));
- cbrace_start = format!("{{\n{}", indent);
- }
- }
- (
- expr.span,
- format!(
- "{}let {} = {};\n{}{}{}",
- cbrace_start,
- snippet_with_applicability(cx, bind_names, "..", &mut applicability),
- snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
- indent,
- snippet_body,
- cbrace_end
- ),
- )
- };
- span_lint_and_sugg(
- cx,
- MATCH_SINGLE_BINDING,
- target_span,
- "this match could be written as a `let` statement",
- "consider using `let` statement",
- sugg,
- applicability,
- );
- },
- PatKind::Wild => {
- if ex.can_have_side_effects() {
- let indent = " ".repeat(indent_of(cx, expr.span).unwrap_or(0));
- let sugg = format!(
- "{};\n{}{}",
- snippet_with_applicability(cx, ex.span, "..", &mut applicability),
- indent,
- snippet_body
- );
- span_lint_and_sugg(
- cx,
- MATCH_SINGLE_BINDING,
- expr.span,
- "this match could be replaced by its scrutinee and body",
- "consider using the scrutinee and body instead",
- sugg,
- applicability,
- );
- } else {
- span_lint_and_sugg(
- cx,
- MATCH_SINGLE_BINDING,
- expr.span,
- "this match could be replaced by its body itself",
- "consider using the match body instead",
- snippet_body,
- Applicability::MachineApplicable,
- );
- }
- },
- _ => (),
- }
-}
-
-/// Returns true if the `ex` match expression is in a local (`let`) statement
-fn opt_parent_let<'a>(cx: &LateContext<'a>, ex: &Expr<'a>) -> Option<&'a Local<'a>> {
- let map = &cx.tcx.hir();
- if_chain! {
- if let Some(Node::Expr(parent_arm_expr)) = map.find(map.get_parent_node(ex.hir_id));
- if let Some(Node::Local(parent_let_expr)) = map.find(map.get_parent_node(parent_arm_expr.hir_id));
- then {
- return Some(parent_let_expr);
- }
- }
- None
-}
-
fn has_multiple_ref_pats<'a, 'b, I>(pats: I) -> bool
where
'b: 'a,
projects / rust.git / commitdiff